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Li L, Ren DD, Zhang PY, Song YP, Li TX, Gao MH, Xu JN, Zhou L, Zeng ZC, Pu Q. Pushing the Limits of Capacitively Coupled Contactless Conductivity Detection for Capillary Electrophoresis. Anal Chem 2024; 96:10356-10364. [PMID: 38863415 DOI: 10.1021/acs.analchem.4c01367] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/13/2024]
Abstract
Capillary electrophoresis with capacitively coupled contactless conductivity detection (CE-C4D) has proven to be an efficient technique for the separation and detection of charged inorganic, organic, and biochemical analytes. It offers several advantages, including cost-effectiveness, nanoliter injection volume, short analysis time, good separation efficiency, suitability for miniaturization, and portability. However, the routine determination of common inorganic cations (NH4+, K+, Na+, Ca2+, Mg2+, and Li+) and inorganic anions (F-, Cl-, Br-, NO2-, NO3-, PO43-, and SO42-) in water quality monitoring typically exhibits limits of detection of about 0.3-1 μM without preconcentration. This sensitivity often proves insufficient for the applications of CE-C4D in trace analysis situations. Here, we explore methods to push the detection limits of CE-C4D through a comprehensive consideration of signal and noise sources. In particular, we (i) studied the model of C4D and its guiding roles in C4D and CE-C4D, (ii) optimized the bandwidth and noise performance of the current-to-voltage (I-V) converter, and (iii) reduced the noise level due to the strong background signal of the background electrolyte by adaptive differential detection. We characterized the system with Li+; the 3-fold signal-to-noise (S/N) detection limit for Li+ was determined at 20 nM, with a linear range spanning from 60 nM to 1.6 mM. Moreover, the optimized CE-C4D method was applied to the analysis of common mixed inorganic cations (K+, Na+, Ca2+, Mg2+, and Li+), anions (F-, Cl-, Br-, NO2-, NO3-, PO43-, and SO42-), toxic halides (BrO3-) and heavy metal ions (Pb2+, Cd2+, Cr3+, Co2+, Ni2+, Zn2+, and Cu2+) at trace concentrations of 200 nM. All electropherograms showed good S/N ratios, thus proving its applicability and accuracy. Our results have shown that the developed CE-C4D method is feasible for trace ion analysis in water quality control.
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Affiliation(s)
- Lin Li
- State Key Laboratory of Applied Organic Chemistry, College of Chemistry and Chemical Engineering, Lanzhou University, Lanzhou 730000, China
| | - Dou-Dou Ren
- State Key Laboratory of Applied Organic Chemistry, College of Chemistry and Chemical Engineering, Lanzhou University, Lanzhou 730000, China
| | - Peng-Yu Zhang
- State Key Laboratory of Applied Organic Chemistry, College of Chemistry and Chemical Engineering, Lanzhou University, Lanzhou 730000, China
| | - Yun-Peng Song
- State Key Laboratory of Applied Organic Chemistry, College of Chemistry and Chemical Engineering, Lanzhou University, Lanzhou 730000, China
| | - Tang-Xiu Li
- State Key Laboratory of Applied Organic Chemistry, College of Chemistry and Chemical Engineering, Lanzhou University, Lanzhou 730000, China
| | - Ming-Hui Gao
- State Key Laboratory of Applied Organic Chemistry, College of Chemistry and Chemical Engineering, Lanzhou University, Lanzhou 730000, China
| | - Jia-Nan Xu
- State Key Laboratory of Applied Organic Chemistry, College of Chemistry and Chemical Engineering, Lanzhou University, Lanzhou 730000, China
| | - Lei Zhou
- State Key Laboratory of Applied Organic Chemistry, College of Chemistry and Chemical Engineering, Lanzhou University, Lanzhou 730000, China
| | - Zhi-Cong Zeng
- State Key Laboratory of Applied Organic Chemistry, College of Chemistry and Chemical Engineering, Lanzhou University, Lanzhou 730000, China
| | - Qiaosheng Pu
- State Key Laboratory of Applied Organic Chemistry, College of Chemistry and Chemical Engineering, Lanzhou University, Lanzhou 730000, China
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Yin B, Zhang Z, Wang Y, Zeng H, Xu J, Li H, Li Y, Zhang M. Compact contactless conductometric, ultraviolet photometric and dual-detection cells for capillary electrophoresis via additive manufacturing. J Chromatogr A 2023; 1712:464469. [PMID: 37924616 DOI: 10.1016/j.chroma.2023.464469] [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: 09/11/2023] [Revised: 10/16/2023] [Accepted: 10/19/2023] [Indexed: 11/06/2023]
Abstract
The growing demand for tailored detectors in capillary electrophoresis (CE), addressing tasks like field deployment or dual-detection analysis, emphasizes the necessity for compact detection cells. In this work, we propose cost-effective and user-friendly additive manufacturing (3D-printing) approaches to produce such miniaturized detection cells suitable for a range of CE applications. Firstly, capacitively-coupled contactless conductivity detection (C4D) cells of different sizes are fabricated by casting low-melting-point alloy into 3D-printed molds. Various designs of Faraday shields are integrated within the cells and compared. A mini-C4D cell (9.5×7.0×7.5 mm3) is produced, with limits of detection for alkaline cations ranging from 8-12 μM in a short-capillary based CE application. Secondly, ultraviolet photometric (UV-PD) detection cells are fabricated using 3D printing. These cells feature two narrow slits with a width of 60 μm, which are positioned along the path of incident and transmission light to facilitate collimation. A deep UV-LED (235 nm or 255 nm) is employed as the light source, and black resin is determined to be the optimal material for 3D printing the UV-PD cell, owing to its superior UV light absorption capabilities. The UV-PD cell is connected to the LED and photodetector through two optical fibers, making it easy to switch the light source and detector. The effective pathlength and stray light percentage for detecting on a 75 μm id capillary are 74 μm and 0.5 %, respectively. Thirdly, a dual-detection cell that combined C4D and UV-PD at a single detection point is proposed. The performance of direct detection by C4D and indirect detection by UV-PD is compared for detecting organic acids. The strategies for developing cost-effective compact detection cells facilitate the versatile integration of multiple detection methods in CE analysis.
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Affiliation(s)
- Bangjie Yin
- School of Life and Environmental Sciences, Guilin University of Electronic Technology, Guilin, Guangxi 541004, China
| | - Zheng Zhang
- School of Life and Environmental Sciences, Guilin University of Electronic Technology, Guilin, Guangxi 541004, China
| | - Yingchun Wang
- School of Life and Environmental Sciences, Guilin University of Electronic Technology, Guilin, Guangxi 541004, China
| | - Hui Zeng
- School of Life and Environmental Sciences, Guilin University of Electronic Technology, Guilin, Guangxi 541004, China.
| | - Jin Xu
- School of Life and Environmental Sciences, Guilin University of Electronic Technology, Guilin, Guangxi 541004, China
| | - Hongzhou Li
- School of Life and Environmental Sciences, Guilin University of Electronic Technology, Guilin, Guangxi 541004, China
| | - Yan Li
- School of Life and Environmental Sciences, Guilin University of Electronic Technology, Guilin, Guangxi 541004, China
| | - Min Zhang
- School of Life and Environmental Sciences, Guilin University of Electronic Technology, Guilin, Guangxi 541004, China.
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A new electromembrane extraction probe for on-line connection with capillary electrophoresis for determination of substances in biological matrices. Talanta 2023; 254:124149. [PMID: 36463806 DOI: 10.1016/j.talanta.2022.124149] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2022] [Revised: 11/20/2022] [Accepted: 11/26/2022] [Indexed: 11/30/2022]
Abstract
A miniature probe for electromembrane extraction is developed and constructed. The tubular probe with an internal volume of 1.1 μL is made of polypropylene hollow fiber with a supported liquid membrane of 85% nitrophenyloctyl ether (NPOE) with 15% bis(2-ethylhexyl)phosphonic acid (DEHP). The probe is connected on-line to the electrophoresis with short separation capillary via an air assisted flow gating interface cast from poly (dimethylsiloxane). The compact instrument is computer controlled via LabView. The probe parameters are tested for extraction of creatinine and basic amino acids from artificial solution and human urine. The sensitivity of the electrophoretic determination after 300 s extraction at 150 V compared to the sensitivity without extraction is 4.9-fold and 2.6-fold higher for creatinine and arginine, respectively. The RSDs for peak area measured from 5 repeated extractions of 50 μM solutions are 7.5%, 7.2%, 8.6% and 9.2% for Crea, Lys, Arg and His, respectively. The probe can be used for all-day measurements. The preparation of the probe is simple and requires no special tool.
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Tůma P, Sommerová B, Koval D, Šiklová M, Koc M. Plasma levels of creatine, 2-aminobutyric acid, acetyl-carnitine and amino acids during fasting measured by counter-current electrophoresis in PAMAPTAC capillary. Microchem J 2023. [DOI: 10.1016/j.microc.2023.108426] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
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Šolínová V, Tůma P, Butnariu M, Kašička V, Koval D. Covalent anionic copolymer coatings with tunable electroosmotic flow for optimization of capillary electrophoretic separations. Electrophoresis 2022; 43:1953-1962. [DOI: 10.1002/elps.202200130] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2022] [Revised: 07/28/2022] [Accepted: 08/08/2022] [Indexed: 11/06/2022]
Affiliation(s)
- Veronika Šolínová
- Institute of Organic Chemistry and Biochemistry of the Czech Academy of Sciences Prague 6 Czech Republic
| | - Petr Tůma
- Department of Hygiene, Third Faculty of Medicine Charles University Prague 10 Czech Republic
| | - Maria Butnariu
- Institute of Organic Chemistry and Biochemistry of the Czech Academy of Sciences Prague 6 Czech Republic
- Department of Analytical Chemistry, Faculty of Science Charles University Prague 2 Czech Republic
| | - Václav Kašička
- Institute of Organic Chemistry and Biochemistry of the Czech Academy of Sciences Prague 6 Czech Republic
| | - Dušan Koval
- Institute of Organic Chemistry and Biochemistry of the Czech Academy of Sciences Prague 6 Czech Republic
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Sensitive monitoring of 3-hydroxybutyrate as an indicator of human fasting by capillary electrophoresis in a PAMAMPS coated capillary. Talanta 2022; 247:123582. [DOI: 10.1016/j.talanta.2022.123582] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2022] [Revised: 05/19/2022] [Accepted: 05/20/2022] [Indexed: 11/20/2022]
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Tůma P. Monitoring of biologically active substances in clinical samples by capillary and microchip electrophoresis with contactless conductivity detection: A review. Anal Chim Acta 2022; 1225:340161. [DOI: 10.1016/j.aca.2022.340161] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2022] [Revised: 07/08/2022] [Accepted: 07/08/2022] [Indexed: 12/11/2022]
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Tůma P, Jaček M, Sommerová B, Dlouhý P, Jarošíková R, Husáková J, Wosková V, Fejfarová V. Monitoring of amoxicilline and ceftazidime in the microdialysate of diabetic foot and serum by capillary electrophoresis with contactless conductivity detection. Electrophoresis 2022; 43:1129-1139. [PMID: 35072285 DOI: 10.1002/elps.202100366] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2021] [Revised: 12/17/2021] [Accepted: 12/23/2021] [Indexed: 11/11/2022]
Abstract
Determination of the broad-spectrum antibiotics amoxicilline (AMX) and ceftazidime (CTZ) in blood serum and microdialysates of the subcutaneous tissue of the lower limbs is performed using CE with contactless conductivity detection (C4 D). Baseline separation of AMX is achieved in 0.5 M acetic acid as the background electrolyte and separation of CTZ in 3.2 M acetic acid with addition of 13% v/v methanol. The CE-C4 D determination is performed in a 25 µm capillary with suppression of the EOF using INST-coating on an effective length of 18 cm and the attained migration time is 4.2 min for AMX and 4.4 min for CTZ. The analysis was performed using 20 µl of serum and 15 µl of microdialysate, treated by the addition of acetonitrile in a ratio of 1/3 v/v and the sample is injected into the capillary using the large volume sample stacking technique. The LOQ attained in the microdialysate is 148 ng/ml for AMX and 339 ng/ml for CTZ, and in serum 143 ng/ml for AMX and 318 ng/ml for CTZ. The CE-C4 D method is employed for monitoring the passage of AMX and CTZ from the blood circulatory system into the subcutaneous tissue at the sites of diabetic ulceration in patients suffering from diabetic foot syndrome and also for measuring the pharmacokinetics following intravenous application of bolus antibiotic doses.
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Affiliation(s)
- Petr Tůma
- Department of Hygiene, Third Faculty of Medicine, Charles University, Prague 10, Czech Republic
| | - Martin Jaček
- Department of Hygiene, Third Faculty of Medicine, Charles University, Prague 10, Czech Republic
| | - Blanka Sommerová
- Department of Hygiene, Third Faculty of Medicine, Charles University, Prague 10, Czech Republic
| | - Pavel Dlouhý
- Department of Hygiene, Third Faculty of Medicine, Charles University, Prague 10, Czech Republic
| | - Radka Jarošíková
- Diabetes Centre, Institute for Clinical and Experimental Medicine, Prague 4, Czech Republic
| | - Jitka Husáková
- Diabetes Centre, Institute for Clinical and Experimental Medicine, Prague 4, Czech Republic
| | - Veronika Wosková
- Diabetes Centre, Institute for Clinical and Experimental Medicine, Prague 4, Czech Republic
| | - Vladimíra Fejfarová
- Diabetes Centre, Institute for Clinical and Experimental Medicine, Prague 4, Czech Republic
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Tůma P, Hložek T, Kamišová J, Gojda J. Monitoring of circulating amino acids in patients with pancreatic cancer and cancer cachexia using capillary electrophoresis and contactless conductivity detection. Electrophoresis 2021; 42:1885-1891. [PMID: 34228371 DOI: 10.1002/elps.202100174] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2021] [Revised: 07/01/2021] [Accepted: 07/02/2021] [Indexed: 11/12/2022]
Abstract
Branched chain amino acids (BCAAs), alanine and glutamine are determined in human plasma by capillary electrophoresis with contactless conductivity detection (CE/C4 D). The baseline separation of five amino acids from other plasma components is achieved on the short capillary effective length of 18 cm in 3.2 mol/L acetic acid with addition of 13% v/v methanol as background electrolyte. Migration times range from 2.01 min for valine to 2.84 min for glutamine, and LODs for untreated plasma are in the interval 0.7-0.9 μmol/L. Sample treatment is based on the addition of acetonitrile to only 15 μL of plasma and supernatant is directly subjected to CE/C4 D. Circulating amino acids are measured in patients with pancreatic cancer and cancer cachexia during oral glucose tolerance test. It is shown that patients with pancreatic cancer and cancer cachexia syndrome exhibit low basal circulating BCAAs and glutamine levels and loss of their insulin-dependent suppression.
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Affiliation(s)
- Petr Tůma
- Third Faculty of Medicine, Department of Hygiene, Charles University, Prague, Czechia
| | - Tomáš Hložek
- Third Faculty of Medicine, Department of Hygiene, Charles University, Prague, Czechia
| | - Jana Kamišová
- Third Faculty of Medicine, Department of Internal Medicine, Charles University and Královské Vinohrady University Hospital, Prague, Czechia.,Centre for the Research on Diabetes, Metabolism and Nutrition, Third Faculty of Medicine, Prague, Czechia
| | - Jan Gojda
- Third Faculty of Medicine, Department of Internal Medicine, Charles University and Královské Vinohrady University Hospital, Prague, Czechia.,Centre for the Research on Diabetes, Metabolism and Nutrition, Third Faculty of Medicine, Prague, Czechia
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10
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Tůma P, Sommerová B, Koval D, Couderc F. Electrophoretic Determination of Symmetric and Asymmetric Dimethylarginine in Human Blood Plasma with Whole Capillary Sample Injection. Int J Mol Sci 2021; 22:2970. [PMID: 33804011 PMCID: PMC7998904 DOI: 10.3390/ijms22062970] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2021] [Revised: 03/09/2021] [Accepted: 03/10/2021] [Indexed: 12/16/2022] Open
Abstract
Asymmetric and symmetric dimethylarginines are toxic non-coded amino acids. They are formed by post-translational modifications and play multifunctional roles in some human diseases. Their determination in human blood plasma is performed using capillary electrophoresis with contactless conductivity detection. The separations are performed in a capillary covered with covalently bonded PAMAPTAC polymer, which generates anionic electroosmotic flow and the separation takes place in the counter-current regime. The background electrolyte is a 750 mM aqueous solution of acetic acid with pH 2.45. The plasma samples for analysis are treated by the addition of acetonitrile and injected into the capillary in a large volume, reaching 94.5% of the total volume of the capillary, and subsequently subjected to electrophoretic stacking. The attained LODs are 16 nm for ADMA and 22 nM for SDMA. The electrophoretic resolution of both isomers has a value of 5.3. The developed method is sufficiently sensitive for the determination of plasmatic levels of ADMA and SDMA. The determination does not require derivatization and the individual steps in the electrophoretic stacking are fully automated. The determined plasmatic levels for healthy individuals vary in the range 0.36-0.62 µM for ADMA and 0.32-0.70 µM for SDMA.
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Affiliation(s)
- Petr Tůma
- Department of Hygiene, Third Faculty of Medicine, Charles University, Ruská 87, 100 00 Prague 10, Czech Republic;
| | - Blanka Sommerová
- Department of Hygiene, Third Faculty of Medicine, Charles University, Ruská 87, 100 00 Prague 10, Czech Republic;
| | - Dušan Koval
- Institute of Organic Chemistry and Biochemistry, The Czech Academy of Sciences, Flemingovo n. 2, 166 10 Prague 6, Czech Republic;
| | - François Couderc
- Laboratoire des IMRCP UMR 5623, University Toulouse III-Paul Sabatier, 31062 Toulouse, France;
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Ta HY, Perquis L, Sarazin C, Guiard B, Meang VO, Collin F, Couderc F. 3-(4-Carboxybenzoyl)quinoline-2-carboxaldehyde labeling for direct analysis of amino acids in plasma is not suitable for simultaneous quantification of tryptophan, tyrosine, valine, and isoleucine by CE/fluorescence. Electrophoresis 2021; 42:1108-1114. [PMID: 33469939 DOI: 10.1002/elps.202000263] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2020] [Revised: 01/14/2021] [Accepted: 01/15/2021] [Indexed: 02/06/2023]
Abstract
Capillary electrophoresis coupled to LED-induced fluorescence detection is a robust and sensitive technique used for amino acids (AA) analysis in biological media, after labeling with 3-(4-carboxybenzoyl)quinoline-2-carboxaldehyde (CBQCA). We wanted to quantitate in plasma tryptophan (Trp), tyrosine (Tyr), valine (Val), and isoleucine (Ile). Among the different labeled AA-CBQCA, Trp has the lowest fluorescence yield, which makes its detection and quantification very difficult in biological samples such as plasma. We tried to improve Trp analysis by CE/LED-induced fluorescence detection to its maximal sensitivity by using large volume sample stacking as a preconcentration step in our analytical protocol. At pH 9.5, this step caused a drop in resolution during the separation of the four AAs and it was therefore necessary to work at pH 10. We have found that Tyr, Val, Ile, and Trp are detected and well separated from the other AAs, but Trp cannot be quantified in plasma samples, mainly because of the low fluorescence yield of the Trp-CBQCA derivative. The recorded LOD is 0.18 μM for Trp-CBQCA in standard solution with a resolution between Trp and Tyr of 1.2, while the LOD is 6 μM in plasma with the same resolution. Trp, Tyr, Val, and Ile are, however, efficiently quantified when using a 3 M acetic acid electrolyte and CE associated with capacitively coupled contactless conductivity detection, which also has the advantage of not requiring derivatization or large volume sample stacking. This article demonstrates, for the CE user, that quantitative analysis of these four AA in mouse plasma can be performed by CE-fluorescence after CBQCA labeling, with the exception of Trp. It can be advantageously replaced by CE/capacitively coupled contactless conductivity detection, the only efficient one for Trp, Tyr, Val, and Ile quantification. In this case, the LOD for Trp is 2 μM. The four AAs are separated with resolution with neighbors above 1.5.
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Affiliation(s)
- Hai Yen Ta
- Laboratoire des IMRCP, UMR 5623, Université Toulouse III Paul Sabatier, Université de Toulouse, Toulouse, France
| | - Lucie Perquis
- Laboratoire des IMRCP, UMR 5623, Université Toulouse III Paul Sabatier, Université de Toulouse, Toulouse, France
| | | | - Bruno Guiard
- CRCA, UMR 5169-Université Toulouse III Paul Sabatier, Université de Toulouse, Toulouse, France
| | - Varravaddheay Ong Meang
- Laboratoire des IMRCP, UMR 5623, Université Toulouse III Paul Sabatier, Université de Toulouse, Toulouse, France
| | - Fabrice Collin
- Laboratoire des IMRCP, UMR 5623, Université Toulouse III Paul Sabatier, Université de Toulouse, Toulouse, France
| | - François Couderc
- Laboratoire des IMRCP, UMR 5623, Université Toulouse III Paul Sabatier, Université de Toulouse, Toulouse, France
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Opekar F, Tůma P. Characterization of various geometric arrangements of "air-assisted" flow gating interfaces for capillary electrophoresis. Electrophoresis 2020; 42:749-755. [PMID: 33191565 DOI: 10.1002/elps.202000305] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2020] [Revised: 11/12/2020] [Accepted: 11/13/2020] [Indexed: 11/11/2022]
Abstract
For connecting flow-through analytical methods with capillary electrophoresis, a chip working in the air-assisted flow gating interface regime is cast from poly(dimethylsiloxane). In the injection space, the exit from the delivery capillary is placed close to the entrance to the separation capillary. Prior to injecting the sample into the separation capillary, the background electrolyte is forced out of the injection space by a stream of air. In the empty space, a drop of the sample with a volume of <100 nL is formed between the exit from the delivery capillary and the entrance into the separation capillary, from which the sample is injected hydrodynamically into the separation capillary. After injection, the injection space is filled with BGE, and the separation can be begun. Three geometric variants for the mutual geometric arrangement of the delivery and separation capillaries were tested: the delivery capillary is placed perpendicular to the separation capillary, from either above or below, or the capillaries are placed axially, that is, directly opposite one another. All of the variants are equivalent from the analytical and separation efficiency viewpoints. The repeatability expressed by RSD is up to 5%. The tested flow gating interface variants are also suitable for continuous and discontinuous sampling at flow rates of the order of units of μL/min. The developed instrument for sequential electrophoretic analysis operates fully automatically and is suitable for rapid sequential monitoring of dynamic processes.
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Affiliation(s)
- František Opekar
- Faculty of Science, Department of Analytical Chemistry, Charles University, Prague, Czechia
| | - Petr Tůma
- Department of Hygiene, Third Faculty of Medicine, Charles University, Prague, Czechia
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Opekar F, Tůma P. Dialysis of one sample drop on-line connected with electrophoresis in short capillary. Talanta 2020; 219:121252. [DOI: 10.1016/j.talanta.2020.121252] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2020] [Revised: 05/26/2020] [Accepted: 05/28/2020] [Indexed: 12/25/2022]
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Large volume sample stacking of antiepileptic drugs in counter current electrophoresis performed in PAMAPTAC coated capillary. Talanta 2020; 221:121626. [PMID: 33076153 DOI: 10.1016/j.talanta.2020.121626] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2020] [Revised: 09/01/2020] [Accepted: 09/02/2020] [Indexed: 12/22/2022]
Abstract
Electrophoretic stacking is developed for sensitive determination of three zwitterionic antiepileptics, namely vigabatrin, pregabalin and gabapentin, in human serum. CE separation is performed in a 25 μm fused silica capillary covalently coated with the copolymer of acrylamide with 5% content of permanently charged 3-acrylamidopropyl trimethylammonium chloride (PAMAPTAC). In background electrolyte of 500 mM acetic acid, the 5% PAMAPTAC generates an anodic electro-osmotic flow with a magnitude of (-18.6 ± 0.5) · 10-9 m2V-1s-1, which acts against the direction of the electrophoretic migration of the analytes. A sample of the antiepileptic prepared in a 25% v/v infusion solution and 75% v/v acetonitrile is injected into the capillary in a large volume attaining a zone length of up to 270 mm. After turning on the separation voltage, the antiepileptics are isotachophoretically focussed behind the zone of Na+ ions with a sensitivity enhancement factor of 78. For the clinical determination of antiepileptics, the human serum is diluted with acetonitrile in a ratio of 1:3 v/v and a zone with a length of 90 mm is injected into the capillary. The method is linear in the 0.025-2.5 μg/mL concentration range; the attained limit of quantification is in the range 18.3-22.8 nmol/L; the within-day precision for the migration time is 0.8-1.2% and for the peak area 1.5-2.4%.
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Separation of anaesthetic ketamine and its derivates in PAMAPTAC coated capillaries with tuneable counter-current electroosmotic flow. Talanta 2020; 217:121094. [PMID: 32498904 DOI: 10.1016/j.talanta.2020.121094] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2020] [Revised: 04/23/2020] [Accepted: 04/25/2020] [Indexed: 02/06/2023]
Abstract
Capillary electrophoretic separation of ketamine, norketamine, hydroxynorketamine, and dehydronorketamine was performed in the counter-current regime under the influence of oppositely-directed electroosmotic flow. For this purpose, the fused silica capillaries were covalently coated with the poly(acrylamide-co-3-acrylamidopropyl trimethylammonium chloride) copolymer (PAMAPTAC). The content of the cationic monomer APTAC in the polymerization mixture varied in the range 0-6 mol. % and the generated electroosmotic flow increased continuously in the 0-20 · 10-9 m2V-1s-1 interval. Importantly, it resulted in improved electrophoretic resolution of ketamine/norketamine, which increased from 0.8 for neutral PAM coating (i.e. 0% PAMAPTAC) to 3.0 for 6% PAMAPTAC. The determination of ketamine and its derivates in rat serum was performed in a 4% PAMAPTAC capillary with an inner diameter of 25 μm. The separation was performed in a 500 mM aqueous solution of acetic acid (pH 2.3). The clinical sample was deproteinized by the addition of acetonitrile to the serum and a large volume of the treated sample was injected directly into the capillary. The achieved limit of detection ranged from 2.2 ng/mL for dehydronorketamine to 4.1 ng/mL for hydroxynorketamine; the intra-day repeatability was 1.0-1.5% for the migration time and 2.8-3.3% for the peak area. The developed methodology was employed for time monitoring of ketamines in rat serum after intra venous administration of low doses of anaesthetic at a level of 2 μg per g of body weight.
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Tůma P, Sommerová B, Daněček V. On-line coupling of capillary electrophoresis with microdialysis for determining saccharides in dairy products and honey. Food Chem 2020; 316:126362. [PMID: 32050115 DOI: 10.1016/j.foodchem.2020.126362] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2019] [Revised: 10/24/2019] [Accepted: 02/04/2020] [Indexed: 12/19/2022]
Abstract
Free sucrose, lactose, galactose, glucose and fructose were determined in yoghurts, milk and honey using on-line coupling of capillary electrophoresis with microdialysis. The dairy products were diluted 50-fold with 10 mmol/L NaOH and sampled using laboratory-made microdialysis probes. The microdialysate was brought to the entrance of the electrophoretic capillary and the coupling consisted in a polydimethylsiloxane (PDMS) cross connector working in the flow-gating interface regime. The electrophoretic analysis was performed in 50 mmol/L NaOH (pH 12.6) background electrolyte, where baseline separation of the five saccharides was achieved in 3.5 min. The LOQs varied in the range 2.3-7.3 mg/L, the number of separation plates varied between 176,000 plates/m for glucose to 326,000 plates/m for galactose and the relative standard deviation (RSD) for ten consecutive analyses of fruit yoghurt was 0.2% for the migration time and 4.4-7.6% for the peak area.
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Affiliation(s)
- Petr Tůma
- Charles University, Third Faculty of Medicine, Department of Hygiene, Ruská 87, 100 00 Prague 10, Czech Republic.
| | - Blanka Sommerová
- Charles University, Third Faculty of Medicine, Department of Hygiene, Ruská 87, 100 00 Prague 10, Czech Republic
| | - Václav Daněček
- Charles University, Third Faculty of Medicine, Department of Biophysics, Ruská 87, 100 00 Prague 10, Czech Republic
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17
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Measuring venous-arterial differences of valine, isoleucine, leucine, alanine and glutamine in skeletal muscles using counter-current electrophoresis with contactless conductivity detection. J Electroanal Chem (Lausanne) 2020. [DOI: 10.1016/j.jelechem.2019.113772] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
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18
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Šimčíková D, Tůma P, Jegorov A, Šimek P, Heneberg P. Rapid methods for the separation of natural mixtures of beauverolides, cholesterol acyltransferase inhibitors, isolated from the fungus
Isaria fumosorosea. J Sep Sci 2020; 43:962-969. [DOI: 10.1002/jssc.201901084] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2019] [Revised: 12/03/2019] [Accepted: 12/09/2019] [Indexed: 12/22/2022]
Affiliation(s)
| | - Petr Tůma
- Charles UniversityThird Faculty of Medicine Prague Czech Republic
| | - Alexandr Jegorov
- Charles UniversityThird Faculty of Medicine Prague Czech Republic
- Biology CentreCzech Academy of Sciences České Budějovice Czech Republic
| | - Petr Šimek
- Biology CentreCzech Academy of Sciences České Budějovice Czech Republic
| | - Petr Heneberg
- Charles UniversityThird Faculty of Medicine Prague Czech Republic
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Opekar F, Hraníček J, Tůma P. Rapid determination of majority cations in yoghurts using on-line connection of capillary electrophoresis with mini-dialysis. Food Chem 2019; 308:125647. [PMID: 31648088 DOI: 10.1016/j.foodchem.2019.125647] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2019] [Revised: 06/27/2019] [Accepted: 10/03/2019] [Indexed: 11/16/2022]
Abstract
An analyser was constructed on the basis of on-line connection of capillary electrophoresis over a short separation path with continuous mini-dialysis sample collection. The developed instrument was employed for simultaneous determination of the majority minerals K+, Ca2+, Na+ and Mg2+ (and possibly NH4+ ions) in commercially available unflavoured yoghurts. The cations are released from the organic structures by digestion with boiling 6 mol/L HCl. They were separated from residues of the organic matrix by a dialysis probe and were transferred to a stream of water. From the continuous stream, the dialysate was injected into the separation capillary through a flow-gating interface. Within the reliability interval, the determined total mineral content was equal to their contents stated on the yoghurt labels and the content determined by flame atomic absorption spectrometry and complexometric titration. The relative standard deviation of the electrophoretic determination is mostly about 5%.
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Affiliation(s)
- František Opekar
- Charles University, Faculty of Science, Department of Analytical Chemistry, Albertov 2030, 128 43 Prague 2, Czech Republic
| | - Jakub Hraníček
- Charles University, Faculty of Science, Department of Analytical Chemistry, Albertov 2030, 128 43 Prague 2, Czech Republic
| | - Petr Tůma
- Charles University, Third Faculty of Medicine, Department of Hygiene, Ruská 87, 100 00 Prague 10, Czech Republic.
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20
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Fan W, Chen X, Ge Y, Jin Y, Jin Q, Zhao J. Single-cell impedance analysis of osteogenic differentiation by droplet-based microfluidics. Biosens Bioelectron 2019; 145:111730. [PMID: 31590074 DOI: 10.1016/j.bios.2019.111730] [Citation(s) in RCA: 34] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2019] [Revised: 09/21/2019] [Accepted: 09/21/2019] [Indexed: 12/17/2022]
Abstract
Single-cell analysis is critical to understanding its heterogeneity and biological processes, such as stem cell differentiation, and elucidating the underlying mechanisms of cellular metabolism. New tools to promote intercellular variability studies help elucidate cellular regulation mechanisms. Here an impedance measurement and analysis system was built to monitor the osteogenic differentiation of single bone marrow mesenchymal stem cells (BM-MSCs) in droplets. The biochip including a microelectrode array was designed based on droplet microfluidics and fabricated. A novel theoretical electrical model was proposed to simulate the electrical properties of cells in the droplets. Impedance measurements showed that single cells are substantially heterogeneous during osteoblast differentiation at different stages (days 0, 7, 14 and 21) and different cell passages (passages 6, 7 and 11). This result was consistent with the appearance of two biomarkers (alkaline phosphatase and calcium nodules), which are the gold standard biomarkers of osteoblastogenesis and differentiation. The device enabled highly efficient single-cell trapping, accurate positioning, and sensitive, label-free and noninvasive impedance measurements of individual cells with multiple channels. This system provides a strategy for exploring the processes of osteoblastogenesis and differentiation at the single-cell level and has substantial potential for applications in the biomedical field.
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Affiliation(s)
- Weihua Fan
- State Key Laboratory of Transducer Technology, Shanghai Institute of Microsystem and Information Technology, Chinese Academy of Sciences, Shanghai, 200050, China; University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Xi Chen
- Department of Pathology, The Third Affiliated Hospital of Soochow University, The First People's Hospital of Changzhou, Changzhou, 213003, China; Orthopaedic Institute, Medical College, Soochow University, Suzhou, 215007, China
| | - Yuqing Ge
- State Key Laboratory of Transducer Technology, Shanghai Institute of Microsystem and Information Technology, Chinese Academy of Sciences, Shanghai, 200050, China.
| | - Yan Jin
- College of Sciences, Shanghai Institute of Technology, Shanghai, 201418, China
| | - Qinghui Jin
- Faculty of Electrical Engineering and Computer Science, Ningbo University, Ningbo, 315211, China.
| | - Jianlong Zhao
- State Key Laboratory of Transducer Technology, Shanghai Institute of Microsystem and Information Technology, Chinese Academy of Sciences, Shanghai, 200050, China.
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Tůma P, Sommerová B, Vaculín Š. Rapid electrophoretic monitoring of the anaesthetic ketamine and its metabolite norketamine in rat blood using a contactless conductivity detector to study the pharmacokinetics. J Sep Sci 2019; 42:2062-2068. [PMID: 30938060 DOI: 10.1002/jssc.201900116] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2019] [Revised: 03/28/2019] [Accepted: 03/28/2019] [Indexed: 01/23/2023]
Abstract
A method of capillary electrophoresis with contactless conductivity detection has been developed for non-enantioselective monitoring the anaesthetic ketamine and its main metabolite norketamine. The separation is performed in a 15 μm capillary with an overall length of 31.5 cm and length to detector of 18 cm; inner surface of the capillary is covered with a commercial coating solution to reduce the electroosmotic flow. In an optimised background electrolyte with composition 2 M acetic acid + 1% v/v coating solution under application of a high voltage of 30 kV, the migration time is 97.1 s for ketamine and 95.8 s for norketamine, with an electrophoretic resolution of 1.2. The attained detection limit was 83 ng/mL (0.3 μmol/L) for ketamine and 75 ng/mL (0.3 μmol/L) for norketamine; the number of theoretic plates for separation of an equimolar model mixture with a concentration of 2 μg/mL was 683 500 plates/m for ketamine and 695 400 plates/m for norketamine. Laboratory preparation of rat blood plasma is based on mixing 10 μL of plasma with 30 μL of acidified acetonitrile, followed by centrifugation. A pharmacokinetic study demonstrated an exponential decrease in the plasma concentration of ketamine after intravenous application and much slower kinetics for intraperitoneal application.
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Affiliation(s)
- Petr Tůma
- Department of Hygiene, Third Faculty of Medicine, Charles University, Prague, Czechia
| | - Blanka Sommerová
- Department of Hygiene, Third Faculty of Medicine, Charles University, Prague, Czechia
| | - Šimon Vaculín
- Department of Physiology, Third Faculty of Medicine, Charles University, Prague, Czechia
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22
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Selective capillary electrophoresis separation of mono and divalent cations within a high-surface area-to-volume ratio multi-lumen capillary. Anal Chim Acta 2019; 1051:41-48. [DOI: 10.1016/j.aca.2018.11.033] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2018] [Revised: 11/14/2018] [Accepted: 11/15/2018] [Indexed: 12/16/2022]
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23
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Tůma P, Sommerová B, Šiklová M. Monitoring of adipose tissue metabolism using microdialysis and capillary electrophoresis with contactless conductivity detection. Talanta 2019; 192:380-386. [DOI: 10.1016/j.talanta.2018.09.076] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2018] [Revised: 09/19/2018] [Accepted: 09/20/2018] [Indexed: 02/02/2023]
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24
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Kubáň P, Hauser PC. Contactless conductivity detection for analytical techniques: Developments from 2016 to 2018. Electrophoresis 2018; 40:124-139. [PMID: 30010203 DOI: 10.1002/elps.201800248] [Citation(s) in RCA: 32] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2018] [Revised: 07/10/2018] [Accepted: 07/10/2018] [Indexed: 01/05/2023]
Abstract
The publications concerning capacitively coupled contactless conductivity detection for the 2-year period from mid-2016 to mid-2018 are covered in this update to the earlier reviews of the series. Relatively few reports on fundamental investigations or new designs have appeared in the literature in this time interval, but the development of new applications with the detection method has continued strongly. Most often, contactless conductivity measurements have been employed for the detection of inorganic or small organic ions in conventional capillary electrophoresis, less often in microchip electrophoresis. A number of other uses, such as detection in chromatography or the gauging of bubbles in streams have also been reported.
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Affiliation(s)
- Pavel Kubáň
- Institute of Analytical Chemistry of the Czech Academy of Sciences, Brno, Czech Republic
| | - Peter C Hauser
- Department of Chemistry, University of Basel, Basel, Switzerland
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25
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Direct sample injection from a syringe needle into a separation capillary. Anal Chim Acta 2018; 1042:133-140. [PMID: 30428980 DOI: 10.1016/j.aca.2018.07.026] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2017] [Revised: 07/05/2018] [Accepted: 07/10/2018] [Indexed: 11/22/2022]
Abstract
An automatic micro-injector was developed for electrophoretic analysis of a microlitre amount of clinical samples, enabling injection of the sample from a Hamilton syringe. The outlet of the syringe needle is located directly opposite the inlet of the separation capillary at a defined distance of the order of hundreds of μm in the injection space. During the injection, the background electrolyte is forced out by air from this space and a drop of the sample is forced out of the syringe by a micro-pump so that it is caught at the entrance to the capillary. From the drop the sample is injected into the capillary by applying a negative pressure pulse or simply by spontaneous injection. The injection space is then filled with background electrolyte, which washes away excess sample and separation is commenced. The injector was tested in electrophoretic separation of a model sample with equimolar concentrations of 100 μM NH4+, K+, Na+, Mg2+ and Li+ in a short capillary with total/effective length of 16.5/11.5 cm. The repeatability of the migration time and peak area expressed as the RSD value is 2% and 4%, respectively. The practical applicability of the injector was verified on the determination of the antiparasitic pentamidine in 10 μL of rat plasma. Electrophoretic separation of pentamidine was performed in 100 mM of acetic acid/NaOH at pH 4.55, the sample consumption per analysis is 125 nL, the separation time is 45 s and the attained LOQ using contactless conductivity detection is 8 μM.
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26
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20th anniversary of axial capacitively coupled contactless conductivity detection in capillary electrophoresis. Trends Analyt Chem 2018. [DOI: 10.1016/j.trac.2018.03.007] [Citation(s) in RCA: 78] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
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Zhao S, Yin D, Du H, Tian X, Chen Y, Zhang W, Yu A, Zhang S. Determination of oxalate and citrate in urine by capillary electrophoresis using solid-phase extraction and capacitively coupled contactless conductivity based on an improved mini-cell. J Sep Sci 2018; 41:2623-2631. [DOI: 10.1002/jssc.201701432] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2017] [Revised: 03/08/2018] [Accepted: 03/09/2018] [Indexed: 11/10/2022]
Affiliation(s)
- Shengnan Zhao
- College of Chemistry & Molecular Engineering; Zhengzhou University; Zhengzhou P. R. China
| | - Dan Yin
- College of Chemistry & Molecular Engineering; Zhengzhou University; Zhengzhou P. R. China
| | - Huifang Du
- College of Chemistry & Molecular Engineering; Zhengzhou University; Zhengzhou P. R. China
| | - Xiangyu Tian
- First Affiliated Hospital of Zhengzhou University; Zhengzhou P. R. China
| | - Yanlong Chen
- College of Chemistry & Molecular Engineering; Zhengzhou University; Zhengzhou P. R. China
| | - Wenfen Zhang
- College of Chemistry & Molecular Engineering; Zhengzhou University; Zhengzhou P. R. China
| | - Ajuan Yu
- College of Chemistry & Molecular Engineering; Zhengzhou University; Zhengzhou P. R. China
| | - Shusheng Zhang
- College of Chemistry & Molecular Engineering; Zhengzhou University; Zhengzhou P. R. China
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28
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KOU W, ZHANG H, KONSTANTIN C, CHEN HW. Charged Bubble Extractive Ionization Mass Spectrometry for Protein Analysis. CHINESE JOURNAL OF ANALYTICAL CHEMISTRY 2017. [DOI: 10.1016/s1872-2040(17)61060-0] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Poinsot V, Ong-Meang V, Ric A, Gavard P, Perquis L, Couderc F. Recent advances in amino acid analysis by capillary electromigration methods: June 2015-May 2017. Electrophoresis 2017; 39:190-208. [PMID: 28805963 DOI: 10.1002/elps.201700270] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2017] [Revised: 07/28/2017] [Accepted: 07/31/2017] [Indexed: 12/13/2022]
Abstract
In the tenth edition of this article focused on recent advances in amino acid analysis using capillary electrophoresis, we describe the most important research articles published on this topic during the period from June 2015 to May 2017. This article follows the format of the previous articles published in Electrophoresis. The new developments in amino acid analysis with CE mainly describe improvements in CE associated with mass spectrometry. Focusing on applications, we mostly describe clinical works, although metabolomics studies are also very important. Finally, works focusing on amino acids in food and agricultural applications are also described.
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Affiliation(s)
- Véréna Poinsot
- Laboratoire des IMRCP, Université Paul Sabatier, Université de Toulouse, France
| | | | - Audrey Ric
- Laboratoire des IMRCP, Université Paul Sabatier, Université de Toulouse, France
| | - Pierre Gavard
- Laboratoire des IMRCP, Université Paul Sabatier, Université de Toulouse, France
| | - Lucie Perquis
- Laboratoire des IMRCP, Université Paul Sabatier, Université de Toulouse, France
| | - François Couderc
- Laboratoire des IMRCP, Université Paul Sabatier, Université de Toulouse, France
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Opekar F, Tůma P. Coaxial flow-gating interface for capillary electrophoresis. J Sep Sci 2017; 40:3138-3143. [DOI: 10.1002/jssc.201700412] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2017] [Revised: 05/22/2017] [Accepted: 05/23/2017] [Indexed: 12/24/2022]
Affiliation(s)
- František Opekar
- Faculty of Science, Department of Analytical Chemistry; Charles University; Prague 2 Czechia
| | - Petr Tůma
- Third Faculty of Medicine, Department of Biochemistry, Cell and Molecular Biology; Charles University; Prague 10 Czechia
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Piešťanský J, Maráková K, Galba J, Kováč A, Mikuš P. Comparison of hydrodynamically closed two-dimensional capillary electrophoresis coupled with ultraviolet detection and hydrodynamically open capillary electrophoresis hyphenated with mass spectrometry in the bioanalysis of varenicline. J Sep Sci 2017; 40:2292-2303. [DOI: 10.1002/jssc.201700098] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2017] [Revised: 03/08/2017] [Accepted: 03/10/2017] [Indexed: 12/16/2022]
Affiliation(s)
- Juraj Piešťanský
- Department of Pharmaceutical Analysis and Nuclear Pharmacy, Faculty of Pharmacy; Comenius University in Bratislava; Bratislava Slovak Republic
- Toxicological and Antidoping Center, Faculty of Pharmacy; Comenius University in Bratislava; Bratislava Slovak Republic
| | - Katarína Maráková
- Department of Pharmaceutical Analysis and Nuclear Pharmacy, Faculty of Pharmacy; Comenius University in Bratislava; Bratislava Slovak Republic
- Toxicological and Antidoping Center, Faculty of Pharmacy; Comenius University in Bratislava; Bratislava Slovak Republic
| | - Jaroslav Galba
- Department of Pharmaceutical Analysis and Nuclear Pharmacy, Faculty of Pharmacy; Comenius University in Bratislava; Bratislava Slovak Republic
- Toxicological and Antidoping Center, Faculty of Pharmacy; Comenius University in Bratislava; Bratislava Slovak Republic
- Institute of Neuroimmunology; Slovak Academy of Sciences; Bratislava Slovak Republic
| | - Andrej Kováč
- Institute of Neuroimmunology; Slovak Academy of Sciences; Bratislava Slovak Republic
| | - Peter Mikuš
- Department of Pharmaceutical Analysis and Nuclear Pharmacy, Faculty of Pharmacy; Comenius University in Bratislava; Bratislava Slovak Republic
- Toxicological and Antidoping Center, Faculty of Pharmacy; Comenius University in Bratislava; Bratislava Slovak Republic
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