1
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Hassan AM, Kelani KM, Hegazy MA, Nadim AH, Tantawy MA. A probe of new molecularly imprinted solid-phase extraction coupled with HPLC-DAD and atomic absorption spectrophotometry for quantification of tetracycline HCl, metronidazole and bismuth subcitrate in combination with their official impurities: Application in dosage form and human plasma. J Chromatogr B Analyt Technol Biomed Life Sci 2024; 1234:124032. [PMID: 38301337 DOI: 10.1016/j.jchromb.2024.124032] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2023] [Revised: 01/21/2024] [Accepted: 01/23/2024] [Indexed: 02/03/2024]
Abstract
The integration of molecular imprinting technique with chromatographic one has a great impact on the assay's selectivity and sensitivity. Herein, a molecularly imprinted solid-phase extraction associated with high performance liquid chromatography (MISPE-HPLC) was employed for simultaneous determination of the co-formulated drugs; tetracycline hydrochloride (TET) and metronidazole (MET), in plasma and in their anti-H-pylori drug for the first time. Two sorts of molecularly imprinted polymers (MIPs) were fabricated using TET and MET as the template molecules, while ethylene glycol dimethacrylate and methacrylic acid were used as a cross-linker and a monomer, respectively. The synthesized MIPs were identified using different techniques. The adsorption-desorption capability of each template was investigated towards its corresponding MIP. The extraction conditions of MISPE was optimized with respect to TET/MIP and MET/MIP sorbent. Bismuth subcitrate (BSC), the third co-formulated drug was analyzed in spiked human plasma using an atomic absorption spectrometric (AAS) method. The performance of the developed methods was assured as per ICH guidelines for analyzing the studied drugs in their pharmaceutical dosage form along with two of their official impurities. In addition, bioanalytical method validation was conducted where linearity was achieved at 2.0-40.0 μg mL-1, 2.0-40.0 μg mL-1 and 5.0-80.0 μg mL-1 for TET, MET and BSC, respectively.
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Affiliation(s)
- Amal M Hassan
- Analytical Chemistry Department, Faculty of Pharmacy, Modern University for Technology and Information, El-hadaba El-Wosta, Mokatam, 5th District, Cairo, Egypt
| | - Khadiga M Kelani
- Analytical Chemistry Department, Faculty of Pharmacy, Modern University for Technology and Information, El-hadaba El-Wosta, Mokatam, 5th District, Cairo, Egypt; Pharmaceutical Analytical Chemistry Department, Faculty of Pharmacy, Cairo University, Cairo, Egypt
| | - Maha A Hegazy
- Pharmaceutical Chemistry Department, Faculty of Pharmacy, Future University in Egypt, Cairo, 11835, Egypt
| | - Ahmed H Nadim
- Pharmaceutical Analytical Chemistry Department, Faculty of Pharmacy, Cairo University, Cairo, Egypt
| | - Mahmoud A Tantawy
- Pharmaceutical Analytical Chemistry Department, Faculty of Pharmacy, Cairo University, Cairo, Egypt; Department of Chemistry, Faculty of Pharmacy, October 6 University, 6 of October City, Giza, Egypt.
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2
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Layman BR, Dick JE. Through-Space Electrochemiluminescence Reveals Bubble Forces at Remote Phase Boundaries. J Am Chem Soc 2024; 146:707-713. [PMID: 38156610 DOI: 10.1021/jacs.3c10505] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2024]
Abstract
Several groups have reported on the curious chemistry and reaction acceleration in confined volumes. These complex multiphase systems most closely resemble natural processes, and new measurement tools are necessary to probe chemistry in such environments. Generally, electrochemiluminescence (ECL) reports on processes immediately near (within a few micrometers) the electrode surface. Here, we introduce through-space ECL, reporting on dynamics of processes far away (100s of μm) from the electrode surface. We achieved this by collecting reflected ECL light. During the heterogeneous oxidation of C2O42- in an aqueous phase adjacent to a 1,2-dichlorethane droplet, CO2 accumulates in the 1,2-dichloroethane droplet. Upon buildup, we demonstrate that a CO2 bubble forms in the nonaqueous phase and is surprisingly trapped at the water|1,2-dichloroethane interface and continues to grow. The co-oxidation of tris(bipyridine)ruthenium(II) in the aqueous phase lights up the electrode surface and reflects off the edges of the bubble, revealing the bubble growth over time even when the bubble is fractions of a millimeter from the surface. We extend our results to quantifying bubble forces at the water-oil interface at remote distances from the electrode surface.
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Affiliation(s)
- Brady R Layman
- Department of Chemistry, Purdue University, West Lafayette, Indiana 47907, United States
| | - Jeffrey E Dick
- Department of Chemistry, Purdue University, West Lafayette, Indiana 47907, United States
- Elmore Family School of Electrical and Computer Engineering, Purdue University, West Lafayette, Indiana 47907, United States
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3
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Ju Y, Zhang H, Jiang Y, Wang W, Kan G, Yu K, Wang X, Liu J, Jiang J. Aqueous microdroplets promote C-C bond formation and sequences in the reverse tricarboxylic acid cycle. Nat Ecol Evol 2023; 7:1892-1902. [PMID: 37679455 DOI: 10.1038/s41559-023-02193-8] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2022] [Accepted: 08/08/2023] [Indexed: 09/09/2023]
Abstract
The reverse tricarboxylic acid cycle (rTCA) is a central anabolic network that uses carbon dioxide (CO2) and may have provided complex carbon substrates for life before the advent of RNA or enzymes. However, non-enzymatic promotion of the rTCA cycle, in particular carbon fixation, remains challenging, even with primordial metal catalysis. Here, we report that the fixation of CO2 by reductive carboxylation of succinate and α-ketoglutarate was achieved in aqueous microdroplets under ambient conditions without the use of catalysts. Under identical conditions, the aqueous microdroplets also facilitated the sequences in the rTCA cycle, including reduction, hydration, dehydration and retro-aldol cleavage and linked with the glyoxylate cycle. These reactions of the rTCA cycle were compatible with the aqueous microdroplets, as demonstrated with two-reaction and four-reaction sequences. A higher selectivity giving higher product yields was also observed. Our results suggest that the microdroplets provide an energetically favourable microenvironment and facilitate a non-enzymatic version of the rTCA cycle in prebiotic carbon anabolism.
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Affiliation(s)
- Yun Ju
- School of Marine Science and Technology, Harbin Institute of Technology at Weihai, Weihai, PR China
- State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, Harbin, PR China
- School of Chemistry and Chemical Engineering, Harbin Institute of Technology, Harbin, PR China
| | - Hong Zhang
- School of Marine Science and Technology, Harbin Institute of Technology at Weihai, Weihai, PR China.
- State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, Harbin, PR China.
| | - Yanxiao Jiang
- School of Marine Science and Technology, Harbin Institute of Technology at Weihai, Weihai, PR China
- State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, Harbin, PR China
| | - Wenxin Wang
- School of Marine Science and Technology, Harbin Institute of Technology at Weihai, Weihai, PR China
- State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, Harbin, PR China
| | - Guangfeng Kan
- School of Marine Science and Technology, Harbin Institute of Technology at Weihai, Weihai, PR China
| | - Kai Yu
- School of Marine Science and Technology, Harbin Institute of Technology at Weihai, Weihai, PR China
- State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, Harbin, PR China
| | - Xiaofei Wang
- School of Marine Science and Technology, Harbin Institute of Technology at Weihai, Weihai, PR China
| | - Jilin Liu
- School of Marine Science and Technology, Harbin Institute of Technology at Weihai, Weihai, PR China
- State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, Harbin, PR China
- School of Chemistry and Chemical Engineering, Harbin Institute of Technology, Harbin, PR China
| | - Jie Jiang
- School of Marine Science and Technology, Harbin Institute of Technology at Weihai, Weihai, PR China.
- State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, Harbin, PR China.
- School of Chemistry and Chemical Engineering, Harbin Institute of Technology, Harbin, PR China.
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4
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Hassan AM, Kelani KM, Hegazy MA, Tantawy MA. Molecular imprinted polymer-based potentiometric approach for the assay of the co-formulated tetracycline HCl, metronidazole and bismuth subcitrate in capsules and spiked human plasma. Anal Chim Acta 2023; 1278:341707. [PMID: 37709450 DOI: 10.1016/j.aca.2023.341707] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2023] [Revised: 08/02/2023] [Accepted: 08/09/2023] [Indexed: 09/16/2023]
Abstract
BACKGROUND An anti-H-pylori co-formulated mixture of tetracycline HCl (TET), metronidazole (MET), and bismuth subcitrate (BSC) is recently available. Only two chromatographic and spectrophotometric methods are reported for determining those drugs simultaneously where the effect of impurities that could be present as well as the biological fluids matrix influence do not be taken into consideration. There is a need to develop an easy-to-use potentiometric technique for analysis of TET, MET, and BSC in their co-formulated capsules, in presence of some official impurities and in spiked human plasma. RESULTS Three carbon paste electrodes (CPEs) were fabricated for this purpose. Being a solid contact ion-selective electrode, CPE suffers from the creation of a water layer affecting its stability and reproducibility. Besides, it has a common problem in differentiation between two drugs carrying the same charge (positively charged TET and MET). Water layer formation was prevented through inserting polyaniline nanoparticles (≈10.0 nm diameter) between solid contact and ion-sensing membrane in the three proposed sensors. TET and MET interference was overcome by synthesizing a corresponding molecular imprinted polymer (MIP) for each drug. The synthesized MIPs were inserted in equivalent sensing membranes and characterized using several techniques. The suggested MIPs have a noticeable enhanced sensitivity in potentiometric determination. The obtained LODs were 5.88 × 10-8, 5.19 × 10-7, and 1.73 × 10-6 M for TET, MET and BSC proposed CPEs, respectively, with corresponding slopes of 57.37, 56.20, and -57.40 mV decade-1. SIGNIFICANCE The proposed potentiometric method makes the detection of the three cited drugs simple, fast, and feasible. This approach is the first for determining three drugs potentiometrically in one combined formulation. The obtained results were compared favorably with previously reported potentiometric methods.
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Affiliation(s)
- Amal M Hassan
- Analytical Chemistry Department, Faculty of Pharmacy, Modern University for Technology and Information, El-hadaba El-Wosta, Mokatam, 5th District, Cairo, Egypt
| | - Khadiga M Kelani
- Analytical Chemistry Department, Faculty of Pharmacy, Modern University for Technology and Information, El-hadaba El-Wosta, Mokatam, 5th District, Cairo, Egypt; Pharmaceutical Analytical Chemistry Department, Faculty of Pharmacy, Cairo University, Kasr el Aini Street, 11562, Cairo, Egypt
| | - Maha A Hegazy
- Pharmaceutical Analytical Chemistry Department, Faculty of Pharmacy, Cairo University, Kasr el Aini Street, 11562, Cairo, Egypt
| | - Mahmoud A Tantawy
- Pharmaceutical Analytical Chemistry Department, Faculty of Pharmacy, Cairo University, Kasr el Aini Street, 11562, Cairo, Egypt; Chemistry Department, Faculty of Pharmacy, October 6 University, 6 October City, Giza, Egypt.
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5
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Khuu T, Schleif T, Mohamed A, Mitra S, Johnson MA, Valdiviezo J, Heindel JP, Head-Gordon T. Intra-cluster Charge Migration upon Hydration of Protonated Formic Acid Revealed by Anharmonic Analysis of Cold Ion Vibrational Spectra. J Phys Chem A 2023; 127:7501-7509. [PMID: 37669457 DOI: 10.1021/acs.jpca.3c03971] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/07/2023]
Abstract
The rates of many chemical reactions are accelerated when carried out in micron-sized droplets, but the molecular origin of the rate acceleration remains unclear. One example is the condensation reaction of 1,2-diaminobenzene with formic acid to yield benzimidazole. The observed rate enhancements have been rationalized by invoking enhanced acidity at the surface of methanol solvent droplets with low water content to enable protonation of formic acid to generate a cationic species (protonated formic acid or PFA) formed by attachment of a proton to the neutral acid. Because PFA is the key feature in this reaction mechanism, vibrational spectra of cryogenically cooled, microhydrated PFA·(H2O)n=1-6 were acquired to determine how the extent of charge localization depends on the degree of hydration. Analysis of these highly anharmonic spectra with path integral ab initio molecular dynamics simulations reveals the gradual displacement of the excess proton onto the water network in the microhydration regime at low temperatures with n = 3 as the tipping point for intra-cluster proton transfer.
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Affiliation(s)
- Thien Khuu
- Sterling Chemistry Laboratory, Department of Chemistry, Yale University, New Haven, Connecticut 06511, United States
| | - Tim Schleif
- Sterling Chemistry Laboratory, Department of Chemistry, Yale University, New Haven, Connecticut 06511, United States
| | - Ahmed Mohamed
- Sterling Chemistry Laboratory, Department of Chemistry, Yale University, New Haven, Connecticut 06511, United States
| | - Sayoni Mitra
- Sterling Chemistry Laboratory, Department of Chemistry, Yale University, New Haven, Connecticut 06511, United States
| | - Mark A Johnson
- Sterling Chemistry Laboratory, Department of Chemistry, Yale University, New Haven, Connecticut 06511, United States
| | - Jesús Valdiviezo
- Pitzer Theory Center, Department of Chemistry, University of California, Berkeley, California 94720, United States
| | - Joseph P Heindel
- Pitzer Theory Center, Department of Chemistry, University of California, Berkeley, California 94720, United States
| | - Teresa Head-Gordon
- Pitzer Theory Center, Department of Chemistry, University of California, Berkeley, California 94720, United States
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6
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Basuri P, Volmer DA. Detecting Early-Stage Intermediates of Free-Radical Oxidative Degradation in Charged Aqueous Microdroplets. J Phys Chem A 2023; 127:7612-7617. [PMID: 37648376 DOI: 10.1021/acs.jpca.3c04143] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/01/2023]
Abstract
We report the detection of early-stage intermediates of spontaneous free-radical oxidation of organic pollutants such as aliphatic amino alcohols and diamines in charged aqueous microdroplets in the ambient atmosphere. We propose that the intrinsic formation of reactive oxygen species at the air-water interface is responsible for the radical oxidation of the sp3 carbon. We suggest that our work will aid the understanding of the degradation mechanisms of organic molecules in the environment.
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Affiliation(s)
- Pallab Basuri
- Institute of Chemistry, Humboldt-Universität zu Berlin, Brook-Taylor-Str. 2, 12489 Berlin, Germany
| | - Dietrich A Volmer
- Institute of Chemistry, Humboldt-Universität zu Berlin, Brook-Taylor-Str. 2, 12489 Berlin, Germany
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7
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Liang Q, Zhu C, Yang J. Water Charge Transfer Accelerates Criegee Intermediate Reaction with H 2O - Radical Anion at the Aqueous Interface. J Am Chem Soc 2023; 145:10159-10166. [PMID: 37011411 DOI: 10.1021/jacs.3c00734] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/05/2023]
Abstract
Criegee intermediates (CIs) are important carbonyl oxides that may react with atmospheric trace chemicals and impact the global climate. The CI reaction with water has been widely studied and is a main channel for trapping CIs in the troposphere. Previous experimental and computational reports have largely focused on reaction kinetic processes in various CI-water reactions. The molecular-level origin of CI's interfacial reactivity at the water microdroplet surface (e.g., as found in aerosols and clouds) is unclear. In this study, by employing the quantum mechanical/molecular mechanical (QM/MM) Born-Oppenheimer molecular dynamics with the local second-order Møller-Plesset perturbation theory, our computational results reveal a substantial water charge transfer up to ∼20% per water, which creates the surface H2O+/H2O- radical pairs to enhance the CH2OO and anti-CH3CHOO reactivity with water: the resulting strong CI-H2O- electrostatic attraction at the microdroplet surface facilitates the nucleophilic attack to the CI carbonyl by water, which may counteract the apolar hindrance of the substituent to accelerate the CI-water reaction. Our statistical analysis of the molecular dynamics trajectories further resolves a relatively long-lived bound CI(H2O-) intermediate state at the air/water interface, which has not been observed in gaseous CI reactions. This work provides insights into what may alter the oxidizing power of the troposphere by the next larger CIs than simple CH2OO and implicates a new perspective on the role of interfacial water charge transfer in accelerating molecular reactions at aqueous interfaces.
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Affiliation(s)
- Qiujiang Liang
- Department of Chemistry, The University of Hong Kong, Hong Kong SAR, People's Republic of China
| | - Chongqin Zhu
- College of Chemistry, Key Laboratory of Theoretical & Computational Photochemistry of Ministry of Education, Beijing Normal University, Beijing 100190, People's Republic of China
| | - Jun Yang
- Department of Chemistry, The University of Hong Kong, Hong Kong SAR, People's Republic of China
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8
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Aqueous microdroplets enable abiotic synthesis and chain extension of unique peptide isomers from free amino acids. Proc Natl Acad Sci U S A 2022; 119:e2212642119. [PMID: 36191178 PMCID: PMC9586328 DOI: 10.1073/pnas.2212642119] [Citation(s) in RCA: 30] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Amide bond formation, the essential condensation reaction underlying peptide synthesis, is hindered in aqueous systems by the thermodynamic constraints associated with dehydration. This represents a key difficulty for the widely held view that prebiotic chemical evolution leading to the formation of the first biomolecules occurred in an oceanic environment. Recent evidence for the acceleration of chemical reactions at droplet interfaces led us to explore aqueous amino acid droplet chemistry. We report the formation of dipeptide isomer ions from free glycine or L-alanine at the air-water interface of aqueous microdroplets emanating from a single spray source (with or without applied potential) during their flight toward the inlet of a mass spectrometer. The proposed isomeric dipeptide ion is an oxazolidinone that takes fully covalent and ion-neutral complex forms. This structure is consistent with observed fragmentation patterns and its conversion to authentic dipeptide ions upon gentle collisions and for its formation from authentic dipeptides at ultra-low concentrations. It also rationalizes the results of droplet fusion experiments that show that the dipeptide isomer facilitates additional amide bond formation events, yielding authentic tri- through hexapeptides. We propose that the interface of aqueous microdroplets serves as a drying surface that shifts the equilibrium between free amino acids in favor of dehydration via stabilization of the dipeptide isomers. These findings offer a possible solution to the water paradox of biopolymer synthesis in prebiotic chemistry.
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9
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Vannoy KJ, Dick JE. Oxidation of Cysteine by Electrogenerated Hexacyanoferrate(III) in Microliter Droplets. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2022; 38:11892-11898. [PMID: 36121813 PMCID: PMC10232928 DOI: 10.1021/acs.langmuir.2c01385] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
Chemical reactivity in droplets is often assumed to mimic reactivity in bulk, continuous water. Here, we study the catalytic oxidation of cysteine by electrogenerated hexacyanoferrate(III) in microliter droplets. These droplets are adsorbed onto glassy carbon macroelectrodes and placed into an immiscible 1,2-dichloroethane phase. We combined cyclic voltammetry, optical microscopy, and finite element simulations to quantify the apparent bimolecular rate constant, kc,app, in microdroplets and bulk water. Statistical analyses reveal that the apparent bimolecular rate constant (kc,app) values formicrodroplets are larger than those in the continuous phase. Reactant adsorption to the droplet boundary has previously been implicated as the cause of such rate accelerations. Finite element modeling of this system suggests that molecular adsorption to the liquid|liquid interface cannot alone account for our observations, implicating kinetics of the bimolecular reaction either at the boundary or throughout the microliter volume. Our results indicate that cysteine oxidation by electrogenerated hexacyanoferrate(III) can be accelerated within a microenvironment, which may have profound implications on understanding biological processes within a cell.
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Affiliation(s)
- Kathryn J Vannoy
- Department of Chemistry, The University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, United States
| | - Jeffrey E Dick
- Department of Chemistry, The University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, United States
- Lineberger Comprehensive Cancer Center, School of Medicine, The University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, United States
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10
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Parmentier EA, Corral Arroyo P, Gruseck R, Ban L, David G, Signorell R. Charge Effects on the Photodegradation of Single Optically Trapped Oleic Acid Aerosol Droplets. J Phys Chem A 2022; 126:4456-4464. [PMID: 35767023 PMCID: PMC9289876 DOI: 10.1021/acs.jpca.2c01370] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
![]()
It has recently been
reported that reactions can occur faster in
microdroplets than in extended condensed matter. The electric charge
of droplets has also been suggested as a possible cause of this phenomenon.
Here, we investigate the influence of electric charges on the photodegradation
of single, optically trapped oleic acid aerosol droplets in the absence
of other reactive species. The temporal evolution of the chemical
composition and the size of droplets with charge states ranging from
0 to 104 elementary charges were retrieved from Raman spectra
and elastic light scattering, respectively. No influence of the droplet
charge was observed, either on the chemical composition or on the
kinetics. Based on a kinetic multilayer model, we propose a reaction
mechanism with the photoexcitation of oleic acid into an excited state,
subsequent decay into intermediates and further photoexcitation of
intermediates and their decay into nonvolatile and volatile products.
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Affiliation(s)
- Evelyne A Parmentier
- Department of Chemistry and Applied Biosciences, ETH Zürich, Vladimir-Prelog-Weg 2, 8093 Zürich, Switzerland
| | - Pablo Corral Arroyo
- Department of Chemistry and Applied Biosciences, ETH Zürich, Vladimir-Prelog-Weg 2, 8093 Zürich, Switzerland
| | - Richard Gruseck
- Department of Chemistry and Applied Biosciences, ETH Zürich, Vladimir-Prelog-Weg 2, 8093 Zürich, Switzerland
| | - Loren Ban
- Department of Chemistry and Applied Biosciences, ETH Zürich, Vladimir-Prelog-Weg 2, 8093 Zürich, Switzerland
| | - Grégory David
- Department of Chemistry and Applied Biosciences, ETH Zürich, Vladimir-Prelog-Weg 2, 8093 Zürich, Switzerland
| | - Ruth Signorell
- Department of Chemistry and Applied Biosciences, ETH Zürich, Vladimir-Prelog-Weg 2, 8093 Zürich, Switzerland
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11
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Sun J, Yin Y, Li W, Jin O, Na N. CHEMICAL REACTION MONITORING BY AMBIENT MASS SPECTROMETRY. MASS SPECTROMETRY REVIEWS 2022; 41:70-99. [PMID: 33259644 DOI: 10.1002/mas.21668] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/06/2020] [Revised: 10/16/2020] [Accepted: 10/22/2020] [Indexed: 06/12/2023]
Abstract
Chemical reactions conducted in different media (liquid phase, gas phase, or surface) drive developments of versatile techniques for the detection of intermediates and prediction of reasonable reaction pathways. Without sample pretreatment, ambient mass spectrometry (AMS) has been applied to obtain structural information of reactive molecules that differ in polarity and molecular weight. Commercial ion sources (e.g., electrospray ionization, atmospheric pressure chemical ionization, and direct analysis in real-time) have been reported to monitor substrates and products by offline reaction examination. While the interception or characterization of reactive intermediates with short lifetime are still limited by the offline modes. Notably, online ionization technologies, with high tolerance to salt, buffer, and pH, can achieve direct sampling and ionization of on-going reactions conducted in different media (e.g., liquid phase, gas phase, or surface). Therefore, short-lived intermediates could be captured at unprecedented timescales, and the reaction dynamics could be studied for mechanism examinations without sample pretreatments. In this review, via various AMS methods, chemical reaction monitoring and mechanism elucidation for different classifications of reactions have been reviewed. The developments and advances of common ionization methods for offline reaction monitoring will also be highlighted.
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Affiliation(s)
- Jianghui Sun
- Key Laboratory of Radiopharmaceuticals Ministry of Education, College of Chemistry, Beijing Normal University, Beijing, People's Republic of China
| | - Yiyan Yin
- Key Laboratory of Radiopharmaceuticals Ministry of Education, College of Chemistry, Beijing Normal University, Beijing, People's Republic of China
| | - Weixiang Li
- Key Laboratory of Radiopharmaceuticals Ministry of Education, College of Chemistry, Beijing Normal University, Beijing, People's Republic of China
| | - Ouyang Jin
- Key Laboratory of Radiopharmaceuticals Ministry of Education, College of Chemistry, Beijing Normal University, Beijing, People's Republic of China
| | - Na Na
- Key Laboratory of Radiopharmaceuticals Ministry of Education, College of Chemistry, Beijing Normal University, Beijing, People's Republic of China
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12
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Brown HM, Doppalapudi KR, Fedick PW. Accelerated synthesis of energetic precursor cage compounds using confined volume systems. Sci Rep 2021; 11:24093. [PMID: 34916525 PMCID: PMC8677777 DOI: 10.1038/s41598-021-02945-1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2021] [Accepted: 11/25/2021] [Indexed: 01/01/2023] Open
Abstract
Confined volume systems, such as microdroplets, Leidenfrost droplets, or thin films, can accelerate chemical reactions. Acceleration occurs due to the evaporation of solvent, the increase in reactant concentration, and the higher surface-to-volume ratios amongst other phenomena. Performing reactions in confined volume systems derived from mass spectrometry ionization sources or Leidenfrost droplets allows for reaction conditions to be changed quickly for rapid screening in a time efficient and cost-saving manner. Compared to solution phase reactions, confined volume systems also reduce waste by screening reaction conditions in smaller volumes prior to scaling. Herein, the condensation of glyoxal with benzylamine (BA) to form hexabenzylhexaazaisowurtzitane (HBIW), an intermediate to the highly desired energetic compound 2,4,6,8,10,12-hexanitro-2,4,6,8,10,12-hexaazaisowurtzitane (CL-20), was explored. Five confined volume systems were compared to evaluate which technique was ideal for forming this complex cage structure. Substituted amines were also explored as BA replacements to screen alternative cage structure intermediates and evaluate how these accelerated techniques could apply to novel reactions, discover alternative reagents to form the cage compound, and improve synthetic routes for the preparation of CL-20. Ultimately, reaction acceleration is ideal for predicting the success of novel reactions prior to scaling up and determining if the expected products form, all while saving time and reducing costs. Acceleration factors and conversion ratios for each reaction were assessed by comparing the amount of product formed to the traditional bulk solution phase synthesis.
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Affiliation(s)
- Hilary M Brown
- Chemistry Division, Naval Air Warfare Center Weapons Division (NAWCWD), United States Navy Naval Air Systems Command (NAVAIR), China Lake, CA, 93555, USA
| | - Karan R Doppalapudi
- Chemistry Division, Naval Air Warfare Center Weapons Division (NAWCWD), United States Navy Naval Air Systems Command (NAVAIR), China Lake, CA, 93555, USA
| | - Patrick W Fedick
- Chemistry Division, Naval Air Warfare Center Weapons Division (NAWCWD), United States Navy Naval Air Systems Command (NAVAIR), China Lake, CA, 93555, USA.
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13
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Feng L, Yin X, Tan S, Li C, Gong X, Fang X, Pan Y. Ammonium Bicarbonate Significantly Accelerates the Microdroplet Reactions of Amines with Carbon Dioxide. Anal Chem 2021; 93:15775-15784. [PMID: 34784192 DOI: 10.1021/acs.analchem.1c03954] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
The reactions between amines and carbon dioxide (CO2) are among the most commonly used and important carbon fixation reactions at present. Microdroplets generated by electrospray ionization (ESI) have been proved to increase the conversion ratio (RC) of amines. In this work, we confirmed that the presence of ammonium bicarbonate (NH4HCO3) in ESI microdroplets significantly increased the RC of amines. The RC went up remarkably with the increase in the concentration of NH4HCO3 from 0.5 to 20 mM. The RC of N,N-dibutyl-1,3-propanediamine (DBPA) reached 93.7% under 20 mM NH4HCO3, which was significantly higher than previous reports. The rise in RC became insignificant when the concentration of NH4HCO3 was increased beyond 20 mM. Further investigations were made on the mechanism of the phenomenon. According to the results, it was suggested that NH4HCO3 decomposed into CO2 and formed microbubbles within the microdroplets of ESI. The microbubbles acted as direct internal CO2 sources. The conversion reactions occurred at the liquid-gas interface. The formation of CO2 microbubbles remarkably increased the total area of the interface, thus promoting the conversion reactions. 13C-labeled experiments confirmed that NH4HCO3 acted as an internal CO2 source. Factors that influenced the RC of the reaction were optimized. Pure water was proved to be the optimal solvent. Lower temperature of the mass spectrometer's entrance capillary was beneficial to the stabilization of the product carbamic acids. The sample flow rate of ESI was crucial to the RC. It determined the initial sizes of the microdroplet. Lower flow rates ensured higher RC of amines. The present work implied that NH4HCO3 could be a superior medium for CO2 capture and utilization. It might offer an alternative choice for future CO2 conversion research studies. In addition, our study also provided evidence that NH4HCO3 decomposed and generated microbubbles in the droplets during ESI. Attention should be paid to this when using NH4HCO3 as an additive in mass spectrometry-based analysis.
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Affiliation(s)
- Lulu Feng
- Department of Chemistry, Zhejiang University, Hangzhou 310027, Zhejiang, China
| | - Xinchi Yin
- Technology Innovation Center of Mass Spectrometry for State Market Regulation, Center for Advanced Measurement Science, National Institute of Metrology, Beijing 100029, China
| | - Siyuan Tan
- Technology Innovation Center of Mass Spectrometry for State Market Regulation, Center for Advanced Measurement Science, National Institute of Metrology, Beijing 100029, China
| | - Chang Li
- College of Instrumentation & Electrical Engineering, Jilin University, Changchun 130061, China
| | - Xiaoyun Gong
- Technology Innovation Center of Mass Spectrometry for State Market Regulation, Center for Advanced Measurement Science, National Institute of Metrology, Beijing 100029, China
| | - Xiang Fang
- Technology Innovation Center of Mass Spectrometry for State Market Regulation, Center for Advanced Measurement Science, National Institute of Metrology, Beijing 100029, China
| | - Yuanjiang Pan
- Department of Chemistry, Zhejiang University, Hangzhou 310027, Zhejiang, China
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14
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Lian J, Wu J, Wu S, Yu W, Wang P, Liu L, Zuo Q. Investigation of viscous effects on droplet generation in a co-flowing step emulsification device. Colloids Surf A Physicochem Eng Asp 2021. [DOI: 10.1016/j.colsurfa.2021.127468] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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15
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Sheven DG, Pervukhin VV. Acceleration of the thermal degradation of PETN in the microdroplets flow reactor. JOURNAL OF HAZARDOUS MATERIALS 2021; 420:126670. [PMID: 34329107 DOI: 10.1016/j.jhazmat.2021.126670] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/11/2021] [Revised: 07/13/2021] [Accepted: 07/14/2021] [Indexed: 06/13/2023]
Abstract
Thermal degradation of pentaerythritol tetranitrate (PETN) was investigated in microdroplets within a heated capillary used as a flow reactor. The thermal degradation was monitored by aerodynamic thermal breakup droplet ionization mass spectrometry. It was shown that the PETN degradation in microdroplets occurs much faster than the bulk reaction (by 4-5 orders of magnitude). The effect of the capillary material [stainless steel (Fe, Cr), copper (Cu), or fused quartz (SiO2)] on the thermal PETN degradation in microdroplets of water or acetonitrile was studied next. The capillary material affected the rate of thermal PETN degradation much more weakly than did the use of microdroplets (pure Cu was most conducive to the degradation). Kinetic parameters (activation energy and the frequency factor) of the PETN degradation for all the studied materials of the flow-through reactor and the solvents were estimated under the assumption that the thermal degradation is a first-order reaction. Implications of the acceleration of PETN degradation in microdroplets are discussed.
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Affiliation(s)
- Dmitriy G Sheven
- Nikolaev Institute of Inorganic Chemistry of SB RAS, Acad. Lavrentieva Ave., 3, 630090 Novosibirsk, Russia.
| | - Viktor V Pervukhin
- Nikolaev Institute of Inorganic Chemistry of SB RAS, Acad. Lavrentieva Ave., 3, 630090 Novosibirsk, Russia
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16
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Batista PR, Penna TC, Ducati LC, Correra TC. p-Aminobenzoic acid protonation dynamics in an evaporating droplet by ab initio molecular dynamics. Phys Chem Chem Phys 2021; 23:19659-19672. [PMID: 34524295 DOI: 10.1039/d1cp01495a] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Protonation equilibria are known to vary from the bulk to microdroplet conditions, which could induce many chemical and physical phenomena. Protonated p-aminobenzoic acid (PABA + H+) can be considered a model for probing the protonation dynamics in an evaporating droplet, as its protonation equilibrium is highly dependent on the formation conditions from solution via atmospheric pressure ionization sources. Experiments using diverse experimental techniques have shown that protic solvents allow formation of the O-protomer (PABA protonated in the carboxylic acid group) stable in the gas phase, while aprotic solvents yield the N-protomer (protonated in the amino group) that is the most stable protomer in solution. In this work, we explore the protonation equilibrium of PABA solvated by different numbers of water molecules (n = 0 to 32) using ab initio molecular dynamics. For n = 8-32, the protonation is either at the NH2 group or in the solvent network. The solvent network interacts with the carboxylic acid group, but there is no complete proton transfer to form the O-protomer. For smaller clusters, however, solvent-mediated proton transfers to the carboxylic acid were observed, both via the Grotthuss mechanism and the vehicle or shuttle mechanism (for n = 1 and 2). Thermodynamic considerations allowed a description of the origins of the kinetic trapping effect, which explains the observation of the solution structure in the gas phase. This effect likely occurs in the final evaporation steps, which are outside the droplet size range covered by previous classical molecular dynamics simulations of charged droplets. These results may be considered relevant in determining the nature of the species observed in the ubiquitous ESI based mass spectrometry analysis, and in general for droplet chemistry, explaining how protonation equilibria are drastically changed from bulk to microdroplet conditions.
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Affiliation(s)
- Patrick R Batista
- Department of Fundamental Chemistry, Institute of Chemistry - University of São Paulo, Av. Prof. Lineu Prestes, 748, Cidade Universitária, São Paulo, SP, Brazil.
| | - Tatiana C Penna
- Department of Fundamental Chemistry, Institute of Chemistry - University of São Paulo, Av. Prof. Lineu Prestes, 748, Cidade Universitária, São Paulo, SP, Brazil.
| | - Lucas C Ducati
- Department of Fundamental Chemistry, Institute of Chemistry - University of São Paulo, Av. Prof. Lineu Prestes, 748, Cidade Universitária, São Paulo, SP, Brazil.
| | - Thiago C Correra
- Department of Fundamental Chemistry, Institute of Chemistry - University of São Paulo, Av. Prof. Lineu Prestes, 748, Cidade Universitária, São Paulo, SP, Brazil.
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17
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Qiu L, Wei Z, Nie H, Cooks RG. Reaction Acceleration Promoted by Partial Solvation at the Gas/Solution Interface. Chempluschem 2021; 86:1362-1365. [PMID: 34508323 DOI: 10.1002/cplu.202100373] [Citation(s) in RCA: 34] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2021] [Revised: 08/27/2021] [Indexed: 01/19/2023]
Abstract
The kinetics of organic reactions of different types in microvolumes (droplets, thin films, and sealed tubes) show effects of gas/solution interfacial area, reaction molecularity and solvent polarity. Partial solvation at the gas/solution interface is a major contributor to the 104 -fold reaction acceleration seen in bimolecular but not unimolecular reactions in microdroplets. Reaction acceleration can be used to manipulate selectivity by solvent choice.
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Affiliation(s)
- Lingqi Qiu
- Department of Chemistry, Purdue University, West Lafayette, Indiana, 47907, United States
| | - Zhenwei Wei
- Department of Chemistry, Purdue University, West Lafayette, Indiana, 47907, United States.,Department of Chemistry, Wuhan University, Wuhan, 430072, P. R. China
| | - Honggang Nie
- Department of Chemistry, Purdue University, West Lafayette, Indiana, 47907, United States.,Beijing National Laboratory for Molecular Science, College of Chemistry and Molecular Engineering, Peking University, Beijing, 100871, P. R. China
| | - R Graham Cooks
- Department of Chemistry, Purdue University, West Lafayette, Indiana, 47907, United States
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18
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Li Y, Huang KH, Morato NM, Cooks RG. Glass surface as strong base, 'green' heterogeneous catalyst and degradation reagent. Chem Sci 2021; 12:9816-9822. [PMID: 34349955 PMCID: PMC8294000 DOI: 10.1039/d1sc02708e] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2021] [Accepted: 06/23/2021] [Indexed: 12/18/2022] Open
Abstract
Systematic screening of accelerated chemical reactions at solid/solution interfaces has been carried out in high-throughput fashion using desorption electrospray ionization mass spectrometry and it provides evidence that glass surfaces accelerate various base-catalyzed chemical reactions. The reaction types include elimination, solvolysis, condensation and oxidation, whether or not the substrates are pre-charged. In a detailed mechanistic study, we provide evidence using nanoESI showing that glass surfaces can act as strong bases and convert protic solvents into their conjugate bases which then act as bases/nucleophiles when participating in chemical reactions. In aprotic solvents such as acetonitrile, glass surfaces act as ‘green’ heterogeneous catalysts that can be recovered and reused after simple rinsing. Besides their use in organic reaction catalysis, glass surfaces are also found to act as degradation reagents for phospholipids with increasing extents of degradation occurring at low concentrations. This finding suggests that the storage of base/nucleophile-labile compounds or lipids in glass containers should be avoided. Glass surfaces are found to be strong bases, ‘green’ heterogeneous catalysts and degradation reagents: glass microspheres act as strong bases to accelerate multiple base-catalyzed reaction types by a factor of 26–2021.![]()
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Affiliation(s)
- Yangjie Li
- Department of Chemistry, Purdue University West Lafayette IN 47907 USA
| | - Kai-Hung Huang
- Department of Chemistry, Purdue University West Lafayette IN 47907 USA
| | - Nicolás M Morato
- Department of Chemistry, Purdue University West Lafayette IN 47907 USA
| | - R Graham Cooks
- Department of Chemistry, Purdue University West Lafayette IN 47907 USA
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19
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Li Y, Mehari TF, Wei Z, Liu Y, Cooks RG. Reaction acceleration at air-solution interfaces: Anisotropic rate constants for Katritzky transamination. JOURNAL OF MASS SPECTROMETRY : JMS 2021; 56:e4585. [PMID: 32686310 DOI: 10.1002/jms.4585] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/01/2020] [Revised: 05/22/2020] [Accepted: 06/04/2020] [Indexed: 06/11/2023]
Abstract
To disentangle the factors controlling the rates of accelerated reactions in droplets, we used mass spectrometry to study the Katritzky transamination in levitated Leidenfrost droplets of different yet constant volumes over a range of concentrations while holding concentration constant by adding back the evaporated solvent. The set of concentration and droplet volume data indicates that the reaction rate in the surface region is much higher than that in the interior. These same effects of concentration and volume were also seen in bulk solutions. Three pyrylium reagents with different surface activity showed differences in transamination reactivity. The conclusion is drawn that reactions with surface-active reactants are subject to greater acceleration, as seen particularly at lower concentrations in systems of higher surface-to-volume ratios. These results highlight the key role that air-solution interfaces play in Katritzky reaction acceleration. They are also consistent with the view that reaction-increased rate constant is at least in part due to limited solvation of reagents at the interface.
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Affiliation(s)
- Yangjie Li
- Department of Chemistry, Purdue University, West Lafayette, Indiana, USA
| | - Tsdale F Mehari
- Department of Chemistry, Purdue University, West Lafayette, Indiana, USA
| | - Zhenwei Wei
- Department of Chemistry, Purdue University, West Lafayette, Indiana, USA
| | - Yong Liu
- Department of Analytical Sciences, MRL, Merck & Co., Inc., Rahway, New Jersey, USA
| | - R Graham Cooks
- Department of Chemistry, Purdue University, West Lafayette, Indiana, USA
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20
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Maringolo V, Aleixo FC, Carvalho AZ, Rocha DL. Exploitation of flow-based procedures for reagentless hydrochlorothiazide determination and accelerated degradation studies of pharmaceutical preparations. ANALYTICAL METHODS : ADVANCING METHODS AND APPLICATIONS 2021; 13:497-503. [PMID: 33437973 DOI: 10.1039/d0ay02070b] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Drug quality assessment and stress testing are important to ensure both treatment efficacy and patient safety. High performance liquid chromatography may be considered a standard technique for pharmaceutical analysis, showing good precision and accuracy, but it also involves relatively high cost and low analytical frequency. Flow injection analysis presents high sample throughput, lower cost and might be used for selective drug analysis with an appropriate assay and/or detector. In this paper, for the first time, photoreactions promoted by UV radiation were employed for reagentless spectrophotometric determination of hydrochlorothiazide. Optimized parameters led to a linear range of 50 to 500 mg L-1, estimated limit of detection of 3.0 mg L-1 and 24 determinations per hour. The use of diluted NaOH solution as a carrier allowed solubilization of hydrochlorothiazide and analysis without organic solvents. The presence of the most common excipients was evaluated and no significant interferences were observed. The results from the analysis of samples by the proposed and by the reference procedures demonstrated accuracy and matching results. The proposed in-line photolysis of the pharmaceutical, performed in 5 min, is a promising alternative to the conventional hydrolytic forced degradation, which requires elevated temperature and prolonged time period. To evaluate the degree of photoconversion, a capillary zone electrophoresis method was developed, which performed well for separations manifesting good analytical frequency and reduced amount of waste. The combination of in-line photodegradation followed by separation by capillary electrophoresis is a promising approach for the stress test of hydrochlorothiazide in pharmaceutical formulations.
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Affiliation(s)
- Vivian Maringolo
- Center on Natural and Human Sciences, Federal University of ABC, 09210-580 - Santo André- SP, Brazil.
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21
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Li YL, Zhou BW, Cheng J, Zhang F, Zhang J, Zhang L, Guo YL. Mass Spectrometry-Based Discovery of New Chemical Scaffold Rearrangement Ions: Aza-biphenylene as a Novel Potent Biradical Agent in Cancer Chemotherapy. Anal Chem 2020; 92:14517-14527. [PMID: 33054169 DOI: 10.1021/acs.analchem.0c02669] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Discovery of a new drug is time-consuming, laborious, and expensive. Herein, a novel integrative strategy for discovering potential new lead compounds has been developed, which was based on the characteristics of mass spectrometry (MS). MS was used to predict the potential forced degradation products (DPs) and metabolites of drugs by electrospray ionization and collision-induced dissociation (CID). Special rearrangement ions representing unique predicted DPs and metabolites were identified. The consistency between the predicted and the measured results was proven by in vitro metabolism and forced degradation of a commercial drug, respectively. From this, new chemical scaffold rearrangement ions named (aza)-biphenylenes, as potent anticancer agents, were discovered. As a representative aza-biphenylene analogue, 2-azabiphenylene was proven in vitro to induce apoptosis and inhibit the growth of various human cancer cells in a dose-dependent manner. Surprisingly, 2-azabiphenylene exhibited the best comparable bioactivity with the positive control sorafenib, but showed significantly lower in vitro cytotoxicity than sorafenib (at least a 5-fold decrease in cytotoxicity) because it could be targeted to the tumor microenvironment at low pH. A biradical mechanism accompanied by a mitochondrion-dependent oxidative stress mechanism was proposed to explore its anticancer mechanism. The highly reactive intermediate aza-biphenylenediyl worked as an active pharmaceutical ingredient and induced apoptosis of cancer cells. This provided the basis for the potential applications of CID-induced special rearrangement ions in developing new lead compounds.
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Affiliation(s)
- Yu-Ling Li
- State Key Laboratory of Organometallic Chemistry and National Center for Organic Mass Spectrometry in Shanghai, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, Shanghai 200032, China
| | - Bo-Wen Zhou
- State Key Laboratory of Organometallic Chemistry and National Center for Organic Mass Spectrometry in Shanghai, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, Shanghai 200032, China
| | - Jie Cheng
- State Key Laboratory of Organometallic Chemistry and National Center for Organic Mass Spectrometry in Shanghai, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, Shanghai 200032, China
| | - Fang Zhang
- State Key Laboratory of Organometallic Chemistry and National Center for Organic Mass Spectrometry in Shanghai, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, Shanghai 200032, China
| | - Jing Zhang
- State Key Laboratory of Organometallic Chemistry and National Center for Organic Mass Spectrometry in Shanghai, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, Shanghai 200032, China
| | - Li Zhang
- State Key Laboratory of Organometallic Chemistry and National Center for Organic Mass Spectrometry in Shanghai, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, Shanghai 200032, China
| | - Yin-Long Guo
- State Key Laboratory of Organometallic Chemistry and National Center for Organic Mass Spectrometry in Shanghai, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, Shanghai 200032, China
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22
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Rovelli G, Jacobs MI, Willis MD, Rapf RJ, Prophet AM, Wilson KR. A critical analysis of electrospray techniques for the determination of accelerated rates and mechanisms of chemical reactions in droplets. Chem Sci 2020; 11:13026-13043. [PMID: 34094487 PMCID: PMC8163298 DOI: 10.1039/d0sc04611f] [Citation(s) in RCA: 54] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2020] [Accepted: 10/25/2020] [Indexed: 12/14/2022] Open
Abstract
Electrospray and Electrosonic Spray Ionization Mass Spectrometry (ESI-MS and ESSI-MS) have been widely used to report evidence that many chemical reactions in micro- and nano-droplets are dramatically accelerated by factors of ∼102 to 106 relative to macroscale bulk solutions. Despite electrospray's relative simplicity to both generate and detect reaction products in charged droplets using mass spectrometry, substantial complexity exists in how the electrospray process itself impacts the interpretation of the mechanism of these observed accelerated rates. ESI and ESSI are both coupled multi-phase processes, in which analytes in small charged droplets are transferred and detected as gas-phase ions with a mass spectrometer. As such, quantitative examination is needed to evaluate the impact of multiple experimental factors on the magnitude and mechanisms of reaction acceleration. These include: (1) evaporative concentration of reactants as a function of droplet size and initial concentration, (2) competition from gas-phase chemistry and reactions on experimental surfaces, (3) differences in ionization efficiency and ion transmission and (4) droplet charge. We examine (1-4) using numerical models, new ESI/ESSI-MS experimental data, and prior literature to assess the limitations of these approaches and the experimental best practices required to robustly interpret acceleration factors in micro- and nano-droplets produced by ESI and ESSI.
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Affiliation(s)
- Grazia Rovelli
- Chemical Sciences Division, Lawrence Berkeley National Laboratory Berkeley 94720 CA USA
| | - Michael I Jacobs
- Chemical Sciences Division, Lawrence Berkeley National Laboratory Berkeley 94720 CA USA
- Department of Chemistry, University of California Berkeley 94720 CA USA
| | - Megan D Willis
- Chemical Sciences Division, Lawrence Berkeley National Laboratory Berkeley 94720 CA USA
| | - Rebecca J Rapf
- Chemical Sciences Division, Lawrence Berkeley National Laboratory Berkeley 94720 CA USA
| | - Alexander M Prophet
- Chemical Sciences Division, Lawrence Berkeley National Laboratory Berkeley 94720 CA USA
- Department of Chemistry, University of California Berkeley 94720 CA USA
| | - Kevin R Wilson
- Chemical Sciences Division, Lawrence Berkeley National Laboratory Berkeley 94720 CA USA
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23
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Wei Z, Li Y, Cooks RG, Yan X. Accelerated Reaction Kinetics in Microdroplets: Overview and Recent Developments. Annu Rev Phys Chem 2020; 71:31-51. [PMID: 32312193 DOI: 10.1146/annurev-physchem-121319-110654] [Citation(s) in RCA: 193] [Impact Index Per Article: 48.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Various organic reactions, including important synthetic reactions involving C-C, C-N, and C-O bond formation as well as reactions of biomolecules, are accelerated when the reagents are present in sprayed or levitated microdroplets or in thin films. The reaction rates increase by orders of magnitude with decreasing droplet size or film thickness. The effect is associated with reactions at the solution-air interface. A key factor is partial solvation of the reagents at the interface, which reduces the critical energy for reaction. This phenomenon is of intrinsic interest and potentially of practical value as a simple, rapid method of performing small-scale synthesis.
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Affiliation(s)
- Zhenwei Wei
- Department of Chemistry, Purdue University, West Lafayette, Indiana 47907, USA;
| | - Yangjie Li
- Department of Chemistry, Purdue University, West Lafayette, Indiana 47907, USA;
| | - R Graham Cooks
- Department of Chemistry, Purdue University, West Lafayette, Indiana 47907, USA;
| | - Xin Yan
- Department of Chemistry, Texas A&M University, College Station, Texas 77842, USA;
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24
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Li Y, Meng L, Wang G, Zhou X, Ouyang Z, Nie Z. A Gas-Phase Reaction Accelerator Using Vortex Flows. Anal Chem 2020; 92:12049-12054. [PMID: 32867491 DOI: 10.1021/acs.analchem.0c02672] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Gas-phase microdroplets have been increasingly used for reaction acceleration. Here, we report the development of a vortex tube as a reaction accelerator. Three types of reactions, viz., aromatization, amination isomerization, and acid-induced cytochrome c unfolding were used to characterize the performance of the vortex tube. During ion transfer from a nanoelectrospray ionization (nanoESI) source to the mass spectrometry (MS) inlet, the generated vortex flows helped droplet desolvation and ion confinement and thus improved the MS intensity by 2-3 orders of magnitude compared with that when the vortex tube was not applied. Like the stirring effect in the bulk phase, the reactants were more sufficiently mixed and reacted in vortices. Therefore, with the same reaction distance, a 2-3-fold improvement of conversion ratios was observed by using the vortices. Notably, the vortex tube enabled the use of flow rate to control the reaction time for ∼60 μs, which was useful for precise control of reaction progress. As a demonstration, the intermediates of the amination isomerization were tracked and the equilibrium constant and rate constant of the cytochrome c unfolding were determined.
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Affiliation(s)
- Yuze Li
- State Key Laboratory of Precision Measurement Technology and Instruments, Department of Precision Instrument, Tsinghua University, Beijing 10084, China.,Beijing National Laboratory for Molecular Sciences, Key Laboratory of Analytical Chemistry for Living Biosystems, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, China.,University of Chinese Academy of Sciences, Beijing 100049, China
| | - Lingwei Meng
- Beijing National Laboratory for Molecular Sciences, Key Laboratory of Analytical Chemistry for Living Biosystems, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, China.,University of Chinese Academy of Sciences, Beijing 100049, China
| | - Guanghui Wang
- National Center for Mass Spectrometry in Beijing, Beijing 100190, China
| | - Xiaoyu Zhou
- State Key Laboratory of Precision Measurement Technology and Instruments, Department of Precision Instrument, Tsinghua University, Beijing 10084, China
| | - Zheng Ouyang
- State Key Laboratory of Precision Measurement Technology and Instruments, Department of Precision Instrument, Tsinghua University, Beijing 10084, China
| | - Zongxiu Nie
- Beijing National Laboratory for Molecular Sciences, Key Laboratory of Analytical Chemistry for Living Biosystems, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, China.,University of Chinese Academy of Sciences, Beijing 100049, China.,National Center for Mass Spectrometry in Beijing, Beijing 100190, China
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25
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Li Y, Hu Y, Logsdon DL, Liu Y, Zhao Y, Cooks RG. Accelerated Forced Degradation of Therapeutic Peptides in Levitated Microdroplets. Pharm Res 2020; 37:138. [PMID: 32651732 DOI: 10.1007/s11095-020-02868-y] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2020] [Accepted: 06/24/2020] [Indexed: 02/03/2023]
Abstract
PURPOSE Forced degradation is critical to probe the stabilities and chemical reactivities of therapeutic peptides. Typically performed in bulk followed by LC-UV or LC-MS analysis, this traditional workflow consists of a reaction/analysis sequence and usually requires half a day to several days to form and measure the desired amounts of degradants. A faster method is needed to study peptide degradation in a shorter time in order to speed up the drug development process. METHODS In the new rapid method developed in this study, peptide degradation occurs in levitated aqueous microdroplets using the Leidenfrost effect. RESULTS This two-minute reaction/analysis workflow allows major degradation pathways of Buserelin, Octreotide, Desmopressin and Leuprorelin to be studied. The reactions include deamidation, disulfide bond cleavage, ether cleavage, peptide bond hydrolysis, and oxidation. CONCLUSIONS The accelerated forced degradation method requires a minimal amount of therapeutic peptide per stress condition, and the appropriate extent of degradation can be readily generated in seconds by adjusting the droplet levitation time. Levitated microdroplets should be applicable in pharmaceutical development to rapidly determine the intrinsic stability of therapeutic peptides and to aid formulation development by screening the effects of excipients on the stability of the peptides. Graphical abstract.
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Affiliation(s)
- Yangjie Li
- 560 Oval Drive, Department of Chemistry, Purdue University, West Lafayette, IN, 47907-1393, USA
| | - Yanyang Hu
- 560 Oval Drive, Department of Chemistry, Purdue University, West Lafayette, IN, 47907-1393, USA
| | - David L Logsdon
- 560 Oval Drive, Department of Chemistry, Purdue University, West Lafayette, IN, 47907-1393, USA
| | - Yong Liu
- Dept. of Analytical Sciences, MRL, Merck & Co., Inc., 126 East Lincoln Ave, Rahway, NJ, 07065, USA
| | - Yuejie Zhao
- Dept. of Analytical Sciences, MRL, Merck & Co., Inc., 126 East Lincoln Ave, Rahway, NJ, 07065, USA
| | - R Graham Cooks
- 560 Oval Drive, Department of Chemistry, Purdue University, West Lafayette, IN, 47907-1393, USA.
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26
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Cao J, Wang Q, An S, Lu S, Jia Q. Facile and efficient preparation of organoimido derivatives of [Mo 6O 19] 2- using accelerated reactions in Leidenfrost droplets. Analyst 2020; 145:4844-4851. [PMID: 32538384 DOI: 10.1039/d0an00578a] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Reaction acceleration is a hot topic in recent years since it is very useful for rapid reaction screening and small-scale synthesis on a short timescale. It is known that the rates of chemical reactions are often accelerated in confined volumes (small droplets or thin films) where the unique chemical reactivities of molecules at the air-droplet/thin film interface, usually different from that in the bulk and gas phases, play a dominant role in acceleration. The Leidenfrost effect was employed to create small levitated droplets with no net charge. These droplets can accelerate many kinds of organic reactions. Our first accelerated synthesis of a series of organoimido-functionalized polyoxometalate (POM) clusters using Leidenfrost droplets with product analysis by electrospray ionization mass spectrometry (ESI-MS) demonstrated that this method can be successfully extended to the synthesis of inorganic/organic hybrids, a very promising area for developing POM-based functional materials. Comparable amounts of synthetic products [Mo6O18(NC6H4R)]2- (R = H (6), m/z 477; p-i-C3H7 (7), m/z 498; p-OCH3 (8), m/z 492; p-NO2 (9), m/z 500) were prepared within minutes in Leidenfrost droplets versus in hours in the corresponding bulk reactions under the same reaction conditions in the presence of the DCC catalyst, suggesting that both concentration and interfacial effects are pivotal in causing reaction acceleration in the Leidenfrost droplet. Compared to the conventional bulk reactions, the acceleration factors (AFs) were 92, 136, 126, and 89 for the four model reactions (1)-(4), respectively. We also found out that substitution affects the rate of reactions occurring in droplets, and hence the magnitude of AF. The rates increase in the order of R = NO2 < H < i-C3H7 < OCH3, in which the electron-donating groups (i.e., R = OCH3, i-C3H7) on the benzene ring are more favorable to the reaction than the electron-withdrawing group (i.e., R = NO2). This experimental result is in good agreement with the DFT calculation which indicates that the free-energy barriers for the direct imidoylization of POM with RNH2 are linearly correlated with the basicity constants (pKb) of amines.
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Affiliation(s)
- Jie Cao
- Key Laboratory of Cluster Science, Ministry of Education of China; Beijing Key Laboratory of Photoelectronic/Electrophotonic Conversion Materials; School of Chemistry, Beijing Institute of Technology, Beijing 100081, China.
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Gnanamani E, Yan X, Zare RN. Chemoselective N‐Alkylation of Indoles in Aqueous Microdroplets. Angew Chem Int Ed Engl 2020; 59:3069-3072. [DOI: 10.1002/anie.201913069] [Citation(s) in RCA: 30] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2019] [Revised: 12/12/2019] [Indexed: 12/11/2022]
Affiliation(s)
- Elumalai Gnanamani
- Department of ChemistryStanford University 333 Campus Drive Stanford CA 94305-5080 USA
- Department of ChemistryFudan University Shanghai 200438 China
| | - Xin Yan
- Department of ChemistryStanford University 333 Campus Drive Stanford CA 94305-5080 USA
- Department of ChemistryTexas A&M University 580 Ross Street College Station TX 77843-3255 USA
| | - Richard N. Zare
- Department of ChemistryStanford University 333 Campus Drive Stanford CA 94305-5080 USA
- Department of ChemistryFudan University Shanghai 200438 China
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28
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Gnanamani E, Yan X, Zare RN. Chemoselective N‐Alkylation of Indoles in Aqueous Microdroplets. Angew Chem Int Ed Engl 2020. [DOI: 10.1002/ange.201913069] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Affiliation(s)
- Elumalai Gnanamani
- Department of Chemistry Stanford University 333 Campus Drive Stanford CA 94305-5080 USA
- Department of Chemistry Fudan University Shanghai 200438 China
| | - Xin Yan
- Department of Chemistry Stanford University 333 Campus Drive Stanford CA 94305-5080 USA
- Department of Chemistry Texas A&M University 580 Ross Street College Station TX 77843-3255 USA
| | - Richard N. Zare
- Department of Chemistry Stanford University 333 Campus Drive Stanford CA 94305-5080 USA
- Department of Chemistry Fudan University Shanghai 200438 China
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29
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Liu Y, Romijn EP, Verniest G, Laukens K, De Vijlder T. Mass spectrometry-based structure elucidation of small molecule impurities and degradation products in pharmaceutical development. Trends Analyt Chem 2019. [DOI: 10.1016/j.trac.2019.115686] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
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30
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Fedick PW, Iyer K, Wei Z, Avramova L, Capek GO, Cooks RG. Screening of the Suzuki Cross-Coupling Reaction Using Desorption Electrospray Ionization in High-Throughput and in Leidenfrost Droplet Experiments. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2019; 30:2144-2151. [PMID: 31392703 DOI: 10.1007/s13361-019-02287-3] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/06/2019] [Revised: 07/07/2019] [Accepted: 07/08/2019] [Indexed: 06/10/2023]
Abstract
Suzuki cross-coupling is a widely performed reaction, typically using metal catalysts under heated conditions. Acceleration of the Suzuki cross-coupling reaction has been previously explored in microdroplets using desorption electrospray ionization mass spectrometry (DESI-MS). Building upon previous work, presented here is the use of a high-throughput DESI-MS screening system to identify optimal reaction conditions. Multiple reagents, bases, and stoichiometries were screened using the automated system at rates that approach 10,000 reaction mixture systems per hour. The DESI-MS system utilizes reaction acceleration in microdroplets to allow rapid screening. The results of screening of an array of reaction mixtures using this technique are presented as product ion images via standard MS imaging software, facilitating quick readout. Instructive comparisons are provided with another method of generating droplets for reaction acceleration-the Leidenfrost technique. Acceleration factors greater than 200 were measured for brominated substrates, paralleling the DESI-MS results. Acceleration factors dropped to near unity with highly substituted pyridines, attributable to a steric effect. The reaction proceeded in the absence of a base in Leidenfrost droplets although no product formation was seen without base in the bulk or in the DESI-MS screening experiments. These differences between Leidenfrost chemistry and the bulk and in droplets formed in high-throughput DESI are tentatively attributed to extremes of pH associated with the surfaces of Leidenfrost droplets.
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Affiliation(s)
- Patrick W Fedick
- Department of Chemistry, Purdue University, West Lafayette, IN, 47907, USA
- Research Department, Chemistry Division, United States Navy-Naval Air Systems Command (NAVAIR), Naval Air Warfare Center, Weapons Division (NAWCWD), China Lake, CA, 93555, USA
| | - Kiran Iyer
- Department of Chemistry, Purdue University, West Lafayette, IN, 47907, USA
| | - Zhenwei Wei
- Department of Chemistry, Purdue University, West Lafayette, IN, 47907, USA
| | - Larisa Avramova
- Department of Chemistry, Purdue University, West Lafayette, IN, 47907, USA
| | - Grace O Capek
- Department of Chemistry, Purdue University, West Lafayette, IN, 47907, USA
| | - R Graham Cooks
- Department of Chemistry, Purdue University, West Lafayette, IN, 47907, USA.
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31
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Marsh BM, Iyer K, Cooks RG. Reaction Acceleration in Electrospray Droplets: Size, Distance, and Surfactant Effects. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2019; 30:2022-2030. [PMID: 31410654 DOI: 10.1007/s13361-019-02264-w] [Citation(s) in RCA: 39] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/18/2019] [Revised: 05/29/2019] [Accepted: 06/20/2019] [Indexed: 05/08/2023]
Abstract
Phenylhydrazone formation from isatin is used to examine the effects on the reaction rate of (i) electrospray emitter distance from the mass spectrometer (MS) inlet, (ii) emitter tip diameter, and (iii) presence of surfactant. Reaction rates are characterized through measurement of conversion ratios. It is found that there is an increase in the conversion ratio as (i) the electrospray source is moved further from the inlet of the mass spectrometer, (ii) smaller sprayer diameters are used, and (iii) when surfactants are present. Each of these experimental operations is associated with an increase in reaction rate and with a decrease in average droplet sizes. The size measurements are made using super resolution microscopy from the "splash" on a collector surface produced by a fluorescent marker sprayed using conditions similar to those used for the reaction mixture. This measurement showed that droplets undergo significant evaporation as a function of distance of flight, thereby increasing their surface to volume ratios. Similarly, the effect of nanoelectrospray emitter size on conversion ratio is also found to be associated with changes in droplet size for which a 4 to 10 times increase in reaction rate is seen using tip diameters ranging from 20 μm down to 1 μm. Finally, the effects of surfactants in producing smaller droplets with corresponding large increases in reaction rate are demonstrated by splash microscopy. These findings point to reaction acceleration being strongly associated with reactions at the surfaces of microdroplets.
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Affiliation(s)
- Brett M Marsh
- Department of Chemistry, Purdue University, West Lafayette, IN, 47907, USA
| | - Kiran Iyer
- Department of Chemistry, Purdue University, West Lafayette, IN, 47907, USA
| | - R Graham Cooks
- Department of Chemistry, Purdue University, West Lafayette, IN, 47907, USA.
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32
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Sahota N, AbuSalim DI, Wang ML, Brown CJ, Zhang Z, El-Baba TJ, Cook SP, Clemmer DE. A microdroplet-accelerated Biginelli reaction: mechanisms and separation of isomers using IMS-MS. Chem Sci 2019; 10:4822-4827. [PMID: 31160956 PMCID: PMC6509997 DOI: 10.1039/c9sc00704k] [Citation(s) in RCA: 45] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2019] [Accepted: 03/28/2019] [Indexed: 01/17/2023] Open
Abstract
Electrospray ionization (ESI) combined with ion mobility spectrometry (IMS) and mass spectrometry (MS) techniques is used to examine the Biginelli reaction in an ensemble of ions generated from droplets.
Electrospray ionization (ESI) combined with ion mobility spectrometry (IMS) and mass spectrometry (MS) techniques is used to examine the Biginelli reaction in an ensemble of ions generated from droplets. We find evidence for rapid dihydropyrimidinone formation from condensation of ethyl acetoacetate, benzaldehyde, and urea on the very short timescales associated with the electrospray process (∼10 μs to ∼1.0 ms). Control bulk-solution reactions show no product formation even after several days. This implies that the in-droplet reaction rate is enhanced by an astonishing factor. Examination of the reaction conditions and characterization of the intermediates en route to product shows evidence for variations in the reaction mechanism. IMS separation shows that the Knoevenagel condensation intermediate from benzaldehyde and ethyl acetoacetate exists as both the cis- and trans-isomer, in a ∼5 to 1 ratio. We suggest that the dramatic acceleration arises because of increased reagent confinement as electrosprayed droplets shrink. The ability of IMS-MS to resolve intermediates (including isomers) provides a new means of understanding reaction pathways.
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Affiliation(s)
- Navneet Sahota
- Department of Chemistry , Indiana University , 800 East Kirkwood Avenue , Bloomington , IN 47405-7102 , USA . ;
| | - Deyaa I AbuSalim
- Department of Chemistry , Indiana University , 800 East Kirkwood Avenue , Bloomington , IN 47405-7102 , USA . ;
| | - Melinda L Wang
- Department of Chemistry , Indiana University , 800 East Kirkwood Avenue , Bloomington , IN 47405-7102 , USA . ;
| | - Christopher J Brown
- Department of Chemistry , Indiana University , 800 East Kirkwood Avenue , Bloomington , IN 47405-7102 , USA . ;
| | - Zhicaho Zhang
- Department of Chemistry , Indiana University , 800 East Kirkwood Avenue , Bloomington , IN 47405-7102 , USA . ;
| | - Tarick J El-Baba
- Department of Chemistry , Indiana University , 800 East Kirkwood Avenue , Bloomington , IN 47405-7102 , USA . ;
| | - Silas P Cook
- Department of Chemistry , Indiana University , 800 East Kirkwood Avenue , Bloomington , IN 47405-7102 , USA . ;
| | - David E Clemmer
- Department of Chemistry , Indiana University , 800 East Kirkwood Avenue , Bloomington , IN 47405-7102 , USA . ;
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33
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Jacobs MI, Davis RD, Rapf RJ, Wilson KR. Studying Chemistry in Micro-compartments by Separating Droplet Generation from Ionization. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2019; 30:339-343. [PMID: 30374662 DOI: 10.1007/s13361-018-2091-y] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/07/2018] [Revised: 10/08/2018] [Accepted: 10/14/2018] [Indexed: 06/08/2023]
Abstract
Recent studies show that reactions inside micron-sized compartments (e.g., droplets, emulsions) can proceed at significantly accelerated rates and with different mechanisms compared to the same reactions in a macroscopic container. Many of these studies use electrospray ionization (ESI) to both generate droplets and to quantify, via mass spectrometry (MS), droplet reaction kinetics. The highly charged and rapidly evaporating droplets produced in ESI make it difficult to examine precisely the underlying cause for droplet-induced rate enhancements. Additionally, interpretation of the spectra from ESI-MS can be complicated by gas-phase ion-molecule and clustering reactions. Here, we use an approach where droplet generation is separated from ionization, in order to decouple the multiple possible sources of acceleration and to examine more closely the potential role of gas-phase chemistry. The production of sugar phosphates from the reaction of phosphoric acid with simple sugars (a reaction that does not occur in bulk solution but has recently been reported to occur in droplets) is measured using this approach to compare reactivity in droplets (i.e., with compartments) with that in the gas phase (i.e., without compartments). The same product ions that have been previously assigned to in droplet reactions are observed with and without compartmentalization. These results suggest that in some cases, gas-phase processes in the ionization region can potentially complicate the quantification and interpretation of accelerated reactions in droplets using ESI-MS (or one of its variants). In such cases, contributions from in-droplet chemistry cannot be ruled out, but we demonstrate that gas-phase processes can be a significant (and possibly dominant) reaction pathway. We suggest that future studies of rate acceleration in droplets be modified to better assess the potential for non-droplet-related processes. Graphical Abstract ᅟ.
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Affiliation(s)
- Michael I Jacobs
- Department of Chemistry, University of California, Berkeley, CA, 94720, USA
- Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
| | - Ryan D Davis
- Department of Chemistry, Trinity University, San Antonio, TX, 78212, USA
| | - Rebecca J Rapf
- Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
| | - Kevin R Wilson
- Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA.
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Wei Z, Zhang X, Wang J, Zhang S, Zhang X, Cooks RG. High yield accelerated reactions in nonvolatile microthin films: chemical derivatization for analysis of single-cell intracellular fluid. Chem Sci 2018; 9:7779-7786. [PMID: 30429986 PMCID: PMC6195031 DOI: 10.1039/c8sc03382j] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2018] [Accepted: 08/21/2018] [Indexed: 12/15/2022] Open
Abstract
The identification of trace components from an individual cell can require derivatization under mild conditions for successful analysis by mass spectrometry (MS).
The identification of trace components from biological media can require derivatization under mild conditions for successful analysis by mass spectrometry (MS). When aqueous droplets (ca. 500 nL) containing a sugar and an amine as reagents are allowed to evaporate they may form long-lasting microthin films in which derivatization reactions can occur fast relative to reaction rates in bulk solution. Evidence is presented that these reactions are heterogeneous in nature and comparisons are made with reactions in pastes and in neat reagent mixtures. Moreover, these thin film reactors can be made stable for the long periods of time that may be necessary to give high product yields. The situation is typified by imine formation from reducing sugars which have reaction times of much more than 1 hour provided that small concentrations (e.g. 20 ppm) of nonvolatile solvents are included. After evaporation of almost all the water, the reaction occurs at an approximately constant rate for the first hour. The rate is two orders of magnitude faster than the reaction in the corresponding homogeneous saturated bulk solution. Conversion of the reagent to the Schiff base product is 67% to 96% efficient in these long-lasting thin films, in sharp contrast to the corresponding derivatization efficiencies in the bulk of less than 1%. This method was used to chemically derivatize and thus to identify, using tandem mass spectrometry, 29 reducing sugars in ca. 1 nL of intracellular fluid from a single onion epidermis cell. A formal description of the kinetics of reversible and irreversible second order reactions in thin films is provided. The effects of thermodynamic and kinetic factors are separated and the measured apparent acceleration factor is shown to represent the ratio of intrinsic rate constants for the microthin film reactor relative to the bulk reaction.
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Affiliation(s)
- Zhenwei Wei
- Department of Chemistry , Purdue University , West Lafayette , IN 47907 , USA .
| | - Xiaochao Zhang
- Department of Chemistry , Tsinghua University , Beijing Key Lab Microanalytical Methods and Instruments , Beijing 100084 , P. R. China .
| | - Jinyu Wang
- Department of Chemistry , Tsinghua University , Beijing Key Lab Microanalytical Methods and Instruments , Beijing 100084 , P. R. China .
| | - Sichun Zhang
- Department of Chemistry , Tsinghua University , Beijing Key Lab Microanalytical Methods and Instruments , Beijing 100084 , P. R. China .
| | - Xinrong Zhang
- Department of Chemistry , Tsinghua University , Beijing Key Lab Microanalytical Methods and Instruments , Beijing 100084 , P. R. China .
| | - R Graham Cooks
- Department of Chemistry , Purdue University , West Lafayette , IN 47907 , USA .
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