Development of sample preparation method for auxin analysis in plants by vacuum microwave-assisted extraction combined with molecularly imprinted clean-up procedure

Effect of ion source polarity and dopants on the detection of auxin plant hormones by ion mobility-mass spectrometry

Ion mobility spectrometry (IMS) equipped with a corona discharge (CD) ion source was used for measurement of three auxin plant hormones including indole-3-acetic acid (IAA), indole-3-propionic acid (IPA), and indole-3-butyric acid (IBA). The measurements were performed in both positive and negative polarities of the CD ion source. Dopant gases NH₃, CCl₄, and CHBr₃ were used to modify the ionization mechanism. A time-of-flight mass spectrometer (TOFMS) orthogonal to the IMS cell was used for identification of the product ions. Density functional theory was used to rationalize formation of the ions, theoretically. The mixtures of the auxins were analyzed by CD-IMS. The separation performance depended on the ion polarity and the dopants. In the positive polarity without dopants, auxins were ionized via protonation and three distinguished peaks were observed. Application of NH₃ dopant resulted in two ionization channels, protonation, and NH₄⁺ attachment leading to peak overlapping. In the negative polarity, two ionization reactions were operative, via deprotonation and O₂^- attachment. The separation of the monomer peaks was not achieved while the peaks of anionic dimers [2 M-H]^- were separated well. The best LOD (4 ng) was obtained in negative polarity with CCl₄ dopant. Methylation (esterification) of IAA improved LODs by about one order.

[Novel adsorption material for solid phase extraction in sample pretreatment of plant hormones]

Plant hormones (PHs) are of significance in plant growth, as they regulate the various processes related to plant growth, development, and resistance. Sensitive and precise quantitative analysis of PHs is a bottleneck in plant science research. Currently, liquid chromatography-tandem mass spectrometry is used for the accurate and efficient detection of PHs. Sample pretreatment is an indispensable step in the chromatography-mass spectrometry analysis of PHs because it directly affects the sensitivity and accuracy of subsequent detection methods. Among various pretreatment methods for PHs, solid phase extraction (SPE) is the most widely used. Various new types of SPE, such as dispersive SPE, magnetic SPE, and solid phase microextraction, have been developed by modifying the extraction cartridge. The choice of adsorption material is the key factor in the abovementioned SPE methods, which has a decisive effect on the extraction, purification, and enrichment effects of the target substance in the sample pretreatment process. Carbon-based materials, including carbon nanotubes, graphene, carbon and nitrogen compounds, as well as organic frameworks, including metal organic frameworks and covalent organic materials, are suitable adsorption materials because of their designable structure, large specific surface area, and good stability. Molecularly imprinted polymers and supramolecular compounds show specific molecular recognition based on host-guest interactions, which can significantly improve the selectivity of sample pretreatment methods. In this paper, SPE-related technology and the abovementioned types of functionalized adsorption materials in the pretreatment of PHs prevalent in the past five years have been reviewed. The related development trends are also summarized.

Recent developments in sample preparation techniques combined with high-performance liquid chromatography: A critical review

This review article compares and contrasts sample preparation techniques coupled with high-performance liquid chromatography (HPLC) and describes applications developed in biomedical, forensics, and environmental/industrial hygiene in the last two decades. The proper sample preparation technique can offer valued data for a targeted application when coupled to HPLC and a suitable detector. Improvements in sample preparation techniques in the last two decades have resulted in efficient extraction, cleanup, and preconcentration in a single step, thus providing a pathway to tackle complex matrix applications. Applications such as biological therapeutics, proteomics, lipidomics, metabolomics, environmental/industrial hygiene, forensics, glycan cleanup, etc., have been significantly enhanced due to improved sample preparation techniques. This review looks at the early sample preparation techniques. Further, it describes eight sample preparation technique coupled to HPLC that has gained prominence in the last two decades. They are (1) solid-phase extraction (SPE), (2) liquid-liquid extraction (LLE), (3) gel permeation chromatography (GPC), (4) Quick Easy Cheap Effective Rugged, Safe (QuEChERS), (5) solid-phase microextraction (SPME), (6) ultrasonic-assisted solvent extraction (UASE), and (7) microwave-assisted solvent extraction (MWASE). SPE, LLE, GPC, QuEChERS, and SPME can be used offline and online with HPLC. UASE and MWASE can be used offline with HPLC but have also been combined with the online automated techniques of SPE, LLE, GPC, or QuEChERS for targeted analysis. Three application areas of biomedical, forensics, and environmental/industrial hygiene are reviewed for the eight sample preparation techniques. Three hundred and twenty references on the eight sample preparation techniques published over the last two decades (2001-2021) are provided. Other older references were included to illustrate the historical development of sample preparation techniques.

Optimization of Vacuum Microwave-Mediated Extraction of Syringoside and Oleuropein from Twigs of Syringa oblata

A vacuum microwave-mediated method was used to extract syringoside and oleuropein from Syringa oblata twigs. The optimal extraction conditions were an ethanol volume fraction of 40%, a liquid-solid ratio of 17 mL/g, 1 h of soaking time, -0.08 MPa of vacuum, a microwave irradiation power of 524 W, and a microwave irradiation time of 8 min. Under optimal parameters, the maximum yields of syringoside (5.92 ± 0.24 mg/g) and oleuropein (4.02 ± 0.18 mg/g) were obtained. The proposed method is more efficient than conventional methods for extracting syringoside and oleuropein from Syringa oblata. Moreover, less energy and time were required. The results implied that vacuum microwave-mediated extraction is a suitable method for the extraction of thermosensitive glycosides such as syringoside and oleuropein.

Trace analysis of multi-class phytohormones in Oryza sativa using different scan modes in high-resolution Orbitrap mass spectrometry: method validation, concentration levels, and screening in multiple accessions

Phytohormones are signaling and regulating metabolites involved in numerous plant processes, including growth, development, and responses to stress. Currently, the focus is on the analysis of multiple phytohormones in order to characterize crosstalk and hormone signaling networks. In this paper, representative phytohormones of the major classes are simultaneously determined in rice tissues by a generic solid-liquid extraction, followed by liquid chromatography and electrospray ionization high-resolution tandem mass spectrometry using a Q-Exactive™ instrument. After a thorough optimization of the sample preparation, the analytical method was fully validated toward the ultra-trace quantification of six a priori selected plant hormones using three scan modes of the quadrupole-Orbitrap instrument: full-scan high-resolution mass spectrometry, targeted single ion monitoring (t-SIM), and t-SIM followed by data-dependent tandem mass spectrometry. Overall, a similar quantitative performance was noticed for the different scan modes. The analytical method was successfully applied to measure basal phytohormone levels in six different rice accessions, comprising Oryza sativa ssp. japonica, indica, and Oryza glaberrima. Hormone concentrations were higher in shoots than in roots or at least similar. Except for a lower level of salicylic acid in shoots of O. glaberrima versus O. sativa, no other differences in hormone levels could be noticed that were dependent of the (sub)species assignment of the analyzed accessions. Making use of the benefits of full-scan high-resolution mass spectrometry, a first post-run suspect screening was performed, suggesting - based on accurate mass measurements and isotopic patterns - the possible presence of about 50 additional plant hormones in the rice tissues. Graphical abstract ᅟ.

A comparative study of primary secondary amino (PSA) and multi-walled carbon nanotubes (MWCNTs) as QuEChERS absorbents for the rapid determination of diazepam and its major metabolites in fish samples by high-performance liquid chromatography-electrospray ionisation-tandem mass spectrometry

BACKGROUND

A simple and fast modified quick, easy, cheap, effective, rugged, and safe (QuEChERS) method is presented for the determination of diazepam and its three major metabolites, nordiazepam, temazepam and oxazepam (benzodiazepines) in fish samples by liquid chromatography-electrospray ionisation-tandem mass spectrometry.

RESULTS

Muscle tissues were extracted with acetonitrile, and then cleaned with primary secondary amino (PSA) adsorbents. The cleanup effect of PSA was compared with that of multi-walled carbon nanotubes (MWCNTs) in term of extraction efficiency. The better results were obtained when PSA was used. The chromatography separation was achieved within 5.0 min on a C18 column. The limit of detection was 0.5 µg kg(-1) and the limit of quantification was 2.5 µg kg(-1). Average recoveries of diazepam and its main metabolites were in the range of 88.5-110.1%, with a relative standard deviation lower than 10.0%.

CONCLUSION

The proposed method for fish samples gives good recoveries, linearity, precision and accuracy.

Simultaneous extraction and HPLC determination of 3-indole butyric acid and 3-indole acetic acid in pea plant by using ionic liquid-modified silica as sorbent

In this study, ionic liquid-modified silica was used as sorbent for simultaneous extraction and preconcentration of 3-indole butyric acid and 3-indole acetic acid in pea plants. The effect of some parameters such as pH and ionic strength of sample solution, amount of sorbent, flow rate of aqueous sample solution and eluent solution, concentration of eluent solution, and temperature were studied for each hormone solution. Percent extraction of 3-indole butyric acid and 3-indole acetic acid was strongly affected by pH of aqueous sample solution. Ionic strength of aqueous phase and temperature showed no serious effects on extraction efficiency of studied plant hormones. Obtained breakthrough volume was 200mL for each of studied hormones. Preconcentration factor for spectroscopic and chromatographic determination of studied hormones was 100 and 4.0×10(3) respectively. Each solid sorbent phase was reusable for almost 10 times of extraction/stripping procedure. Relative standard deviations of extraction/stripping processes of 3-indole butyric acid and 3-indole acetic acid were 2.79% and 3.66% respectively. The calculated limit of detections for IBA and IAA were 9.1×10(-2)mgL(-1) and 1.6×10(-1)mgL(-1) respectively.

An effective vacuum assisted extraction method for the optimization of labdane diterpenoids from Andrographis paniculata by response surface methodology

An effective vacuum assisted extraction (VAE) technique was proposed for the first time and applied to extract bioactive components from Andrographis paniculata. The process was carefully optimized by response surface methodology (RSM). Under the optimized experimental conditions, the best results were obtained using a boiling temperature of 65 °C, 50% ethanol concentration, 16 min of extraction time, one extraction cycles and a 12:1 liquid-solid ratio. Compared with conventional ultrasonic assisted extraction and heat reflux extraction, the VAE technique gave shorter extraction times and remarkable higher extraction efficiency, which indicated that a certain degree of vacuum gave the solvent a better penetration of the solvent into the pores and between the matrix particles, and enhanced the process of mass transfer. The present results demonstrated that VAE is an efficient, simple and fast method for extracting bioactive components from A. paniculata, which shows great potential for becoming an alternative technique for industrial scale-up applications.

Molecular imprinting science and technology: a survey of the literature for the years 2004-2011

Herein, we present a survey of the literature covering the development of molecular imprinting science and technology over the years 2004-2011. In total, 3779 references to the original papers, reviews, edited volumes and monographs from this period are included, along with recently identified uncited materials from prior to 2004, which were omitted in the first instalment of this series covering the years 1930-2003. In the presentation of the assembled references, a section presenting reviews and monographs covering the area is followed by sections describing fundamental aspects of molecular imprinting including the development of novel polymer formats. Thereafter, literature describing efforts to apply these polymeric materials to a range of application areas is presented. Current trends and areas of rapid development are discussed.

Ionic liquid-based vacuum microwave-assisted extraction followed by macroporous resin enrichment for the separation of the three glycosides salicin, hyperin and rutin from Populus bark

An effective ionic liquid vacuum microwave-assisted method was developed for extraction of the thermo- and oxygen-sensitive glycosides salicin, hyperin and rutin from Populus bark due to the strong solvating effects of ionic liquids on plant cell walls. In this study, [C₄mim]BF₄ solution was selected as the extracting solution for extraction of the target analytes. After optimization by single factor experiments and response surface methodology, the optimum condition parameters were achieved, which included 1.0 M [C₄mim]BF₄, 2 h soaking time, −0.08 MPa vacuum, 20 min microwave irradiation time, 400 W microwave irradiation power and 25 mL/g liquid/solid ratio. Under the optimum conditions, higher extraction yields of salicin (35.53 mg/g), hyperin (1.32 mg/g) and rutin (2.40 mg/g) were obtained. Compared with other extraction methods, the developed method provided higher yields of the three target components after a relatively shorter extraction time (20 min). No obvious degradation of the target analytes was observed under the optimum conditions in performed stability studies and the proposed method had a high reproducibility. Meanwhile, after adsorption and desorption on macroporous D101 resin, the target analytes can be effectively separated from the [C₄mim]BF₄ ionic liquid extraction solution and the yields of salicin, hyperin and rutin were 89%, 82% and 84%, respectively. The recovered [C₄mim]BF₄ ionic liquid presented a good extraction effect on the three analytes after recycling five times.

Selective extraction and determination of catecholamines in urine samples by using a dopamine magnetic molecularly imprinted polymer and capillary electrophoresis

A rapid and selective method for the extraction and determination of catecholamines (CLs) from urine samples has been successfully developed using a magnetic molecularly imprinted polymer (MMIP) as a sorbent material. The MMIP has been prepared using dopamine hydrochloride (DA) as template molecule, methacrylic acid (MAA) as functional monomer, ethylene glycol dimethacrylate (EDMA) as cross-linking agent and Fe(3)O(4) magnetite as magnetic component. The extraction was carried out by stirring urine samples with the magnetic polymer. When the extraction was completed, the MMIP, together with the captured analytes, was easily separated from the sample matrix by an adscititious magnet. The analytes desorbed from the MMIP were determined by capillary electrophoresis (CE). It was shown that the MMIP had high affinity and selectivity toward DA and other structurally related CLs such as 3-methoxytyramine hydrochloride (MT), DL-normetanephrine hydrochloride (NME), DL-norephinephrine hydrochloride (NE) and (±) epinephrine (E). Different parameters affecting the extraction efficiency were evaluated in order to achieve the optimal pre-concentration of the analytes and to reduce non-specific interactions. Under the optimal conditions, the CL limits of detection were at the 0.04-0.06 μM range. The relative standard deviations of migration time and response ranged from 0.7% to 1.4% and from 2.9% to 5.5%, respectively. The proposed method was successfully applied to determine CLs, including MT, NME, DA, NE and E in human urine samples.

Analytical methods for tracing plant hormones

Plant hormones play important roles in regulating numerous aspects of plant growth, development, and response to stress. In the past decade, more analytical methods for the accurate identification and quantitative determination of trace plant hormones have been developed to better our understanding of the molecular mechanisms of plant hormones. As sample preparation is often the bottleneck in analysis of plant hormones in biological samples, this review firstly discusses sample preparation techniques after a brief introduction to the classes, roles, and methods used in the analysis of plant hormones. The analytical methods, especially chromatographic techniques and immuno-based methods, are reviewed in detail, and their corresponding advantages, limitations, applications, and prospects are also discussed. This review mainly covers reports published from 2000 to the present on methods for the analysis of plant hormones.