Screening and Identification of Potential Abscisic Acid Catabolites by Chemical Labeling-Assisted Ultrahigh-Performance Liquid Chromatography Coupled with High-Resolution Mass Spectrometry.

In this study, a screening strategy was established based on ultrahigh-performance liquid chromatography coupled with high-resolution mass spectrometry assisted by chemical isotope labeling (CIL-UPLC-HRMS) for screening and identifying abscisic acid (ABA) catabolites. Based on the structures of known ABA catabolites, this strategy first proposed the structures of catabolites to be discovered. Afterward, a pair of isotope reagents ,-2-dimethylaminoethylamine (DMED) and -DMED were used as labeling reagents to label the carboxyl groups in ABA and its catabolites.

Neophaseic acid catabolism in the 9'-hydroxylation pathway of abscisic acid in Arabidopsis thaliana.

Abscisic acid (ABA) hydroxylation is an important pathway for ABA inactivation and homeostasis maintenance. Here, we discover a new downstream catabolite of neophaseic acid (neoPA) in the ABA 9'-hydroxyl pathway and identify it as epi-neodihydrophaseic acid (epi-neoDPA) by comparing its accurate mass, retention time, and MS spectra with those of our chemically synthesized epi-neoDPA. Analyses of Arabidopsis seed germination and ABA-related gene expression reveal that neoPA rather than epi-neoDPA possesses ABA-like hormonal activity.

Highly sensitive analysis of cyanogenic glycosides in cold-pressed flaxseed oil by employing cigarette filter fiber-based SPE coupled with ultra-performance liquid chromatography-tandem mass spectrometry.

In this study, a highly sensitive method for analysis of 4 cyanogenic glycosides (CNGs) in cold-pressed flaxseed oil was developed by using cigarette filter fiber-based SPE and ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS). The cold-pressed flaxseed oil was diluted with 5% (v/v) isopropanol/n-hexane solution and loaded to a cigarette filters fiber-based SPE column for CNG enrichment and purification. Under optimized conditions, four CNGs could be detected with limits of detection ranging from 1.

Sensitive analysis of trehalose-6-phosphate and related sugar phosphates in plant tissues by chemical derivatization combined with hydrophilic interaction liquid chromatography-tandem mass spectrometry.

Trehalose-6-phosphate (T6P) is an important signaling metabolite that is involved in many physiological processes. However, the mechanism of the biological functions of T6P is not fully understood. Quantification of T6P in plants will be beneficial to elucidate the mechanism.

Simultaneous Determination of Abscisic Acid and Its Catabolites by Hydrophilic Solid-Phase Extraction Combined with Ultra High Performance Liquid Chromatography-Tandem Mass Spectrometry.

An efficient and selective pretreatment method of one-step hydrophilic interaction chromatography-based solid phase extraction (HILIC SPE) was developed using silica as the sorbent to quickly and sensitively detect endogenous ABA and its five catabolites in fresh Oryza sativa tissues. The extracted analytes were sensitively quantified with ultra high performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS). Under the optimized conditions, good linearity of the developed analytical method was obtained in the range of 0.

Sensitive determination of brassinosteroids by solid phase boronate affinity labeling coupled with liquid chromatography-tandem mass spectrometry.

Brassinosteroids (BRs) are regarded as the sixth plant hormone that is widely distributed in the plant kingdom. Sensitive quantification of BRs will be greatly benefit to illuminate the detail mechanisms about how BRs play crucial role in plant developmental processes such as cell division, cell expansion, cytodifferentiation, seed germination, vegetative growth and resisting biological or abiotic stress. In the current study, we developed a method for rapid and sensitive determination of endogenous BRs in plant tissues by combining LC-MS and a novel sample preparation strategy, in which the plant tissue extract was supplied to solid phase boronate affinity labeling and extraction, followed by desorption and salt-induced phase transition extraction for further purification.

Improved methodology for analysis of multiple phytohormones using sequential magnetic solid-phase extraction coupled with liquid chromatography-tandem mass spectrometry.

Phytohormones are special small molecules that play important role in plant growth and development at trace levels. Quantification of multiple phytohormones will be great helpful for researches about cross-talks that plant hormones regulate the responses of plants against both biotic and abiotic stresses by means of synergistic or antagonistic interactions. In the current study, we developed a method for profiling of phytohormones in one small sample, including indole-3-acetic acid, abscisic acid, jasmonic acid, gibberellins, cytokinins and brassinosteroids.

A rapid approach to investigate spatiotemporal distribution of phytohormones in rice.

Background: Phytohormones play crucial roles in almost all stages of plant growth and development. Accurate and simultaneous determination of multiple phytohormones enabled us to better understand the physiological functions and the regulatory networks of phytohormones. However, simultaneous determination of multiple phytohormones in plant is still a challenge due to their low concentrations, structural and chemical diversity, and complex matrix of plant tissues.

Sequential solvent induced phase transition extraction for profiling of endogenous phytohormones in plants by liquid chromatography-mass spectrometry.

In the current study, a novel method for high-throughput and sensitive determination of 12 phytohormones in plants was developed by using sequential solvent induced phase transition extraction (SIPTE) coupled with ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS). In sequential SIPTE, 0.1% formic acid (v/v) and 50mM NaHCO3 aqueous solution were used for enrichment and purification of alkaline and acidic phytohormones from the acetonitrile extract of plant tissues in sequence, in which hydrophobic solvent (toluene) was added to the acetonitrile aqueous mixture for driving the phase separation.

Profiling of phytohormones in rice under elevated cadmium concentration levels by magnetic solid-phase extraction coupled with liquid chromatography tandem mass spectrometry.

Phytohormones, a collection of signal small molecules with various structures, regulate a series of physiological processes of plants. For instance, they regulate the growth and development, response to biotic and abiotic stresses. Quantification of trace endogenous phytohormones is essential to elucidate their molecular mechanisms in response to stresses.

Magnetic graphene as modified quick, easy, cheap, effective, rugged and safe adsorbent for the determination of organochlorine pesticide residues in tobacco.

In this study, magnetic graphene was used as modified quick, easy, cheap, effective, rugged and safe (QuEChERS) adsorbent for the determination of organochlorine pesticide (OCPs) residues in tobacco. To achieve the optimum conditions of modified QuEChERS procedure toward target analytes, several parameters affecting the clean-up efficiency including the amount of the adsorbent and clean-up time were investigated. Under the optimized conditions, a method for the determination of 26 OCPs residues in tobacco was established by coupling the modified QuEChERS procedure to on-line gel permeation chromatography-gas chromatography-tandem mass spectrometry (on-line GPC-GC-MS(2)).

In-syringe dispersive solid phase extraction: a novel format for electrospun fiber based microextraction.

A novel in-syringe dispersive solid phase extraction (dSPE) system using electrospun silica fibers as adsorbents has been developed in the current work. A few milligrams of electrospun silica fibers were incubated in sample solution in the barrel of a syringe for microextraction assisted by vortex. Due to the benefit of dispersion and the high mass transfer rate of the sub-microscale electrospun silica fibers, the extraction equilibrium was achieved in a very short time (less than 1 min).

Rapid and high-throughput determination of endogenous cytokinins in Oryza sativa by bare Fe3O4 nanoparticles-based magnetic solid-phase extraction.

A rapid method was developed for determination of endogenous cytokinins (CKs) based on magnetic solid-phase extraction (MSPE) followed by ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS). We illustrated the hydrophilic character of bare Fe3O4 nanoparticles that were directly used as a MSPE sorbent for rapid enrichment of endogenous CKs from complex plant extract. To the best of our knowledge, this is the first report of bare Fe3O4 directly used as efficient extraction sorbent to enrich target CKs based on hydrophilic interaction.

A simple sample preparation approach based on hydrophilic solid-phase extraction coupled with liquid chromatography-tandem mass spectrometry for determination of endogenous cytokinins.

Cytokinins (CKs), a vital family of phytohormones, play important roles in the regulation of shoot and root development. However, the quantification of CKs in plant samples is frequently affected by the complex plant matrix. In the current study, we developed a simple, rapid and efficient hydrophilic interaction chromatography-solid phase extraction (HILIC-SPE) method for CKs purification.

Rapid determination of endogenous cytokinins in plant samples by combination of magnetic solid phase extraction with hydrophilic interaction chromatography-tandem mass spectrometry.

A 2-acrylamido-2-methyl-1-propanesulfonic acid-co-ethylene glycol dimethacrylate (Fe₃O₄/SiO₂/P(AMPS-co-EGDMA)) copolymer was prepared and used as a magnetic solid phase extraction (MSPE) medium for recovery of endogenous cytokinins (CKs) from plant extracts. This magnetic porous polymer was characterized by electron microscopy, nitrogen sorption experiments, elemental analysis and Fourier-transformed infrared spectroscopy. It was demonstrated to have high extraction capacity toward CKs in plants due to its specificity, surface area and porous structure.