Girard's Reagent Research Articles

Biological Activity Evaluation of Phenolic Isatin-3-Hydrazones Containing a Quaternary Ammonium Center of Various Structures.

A series of new isatin-3-hydrazones bearing different ammonium fragments was synthesized by a simple and easy work-up reaction of Girard's reagents analogs with 1-(3,5-di-tert-butyl-4-hydroxybenzyl)isatin. All derivatives have been shown to have antioxidant properties. In terms of bactericidal activity against gram-positive bacteria, including methicillin-resistant strains of Staphylococcus aureus, the best compounds are 3a, 3e, and 3m, bearing octyl, acetal, and brucine ammonium centers, respectively. In addition, brucine and quinine derivatives 3l, and 3j exhibit platelet antiaggregation activity at the level of acetylsalicylic acid, and this series of isatin derivatives does not adversely affect the hemostasis system as a whole. Thus, all the obtained results can lay the groundwork for future pharmaceutical developments for the creation of effective antibacterial drugs with reduced systemic toxicity due to the presence of antioxidant properties.

Hydrazide-based reactive matrices for the sensitive detection of aldehydes and ketones by MALDI mass spectrometry imaging.

A one-step, on-tissue chemical derivatisation method for MALDI mass spectrometry imaging was found to improve the detectability of aldehydes and ketones by charge-tagging. The developed reactive matrices, containing a UV-chromophore, ionisable moiety and hydrazide group, showed an equal or higher detection efficiency than Girard's reagent P, enabling improved imaging of brain metabolites without the need for additional co-matrices.

Enhanced Thermal and Mechanical Properties of Cardanol Epoxy/Clay-Based Nanocomposite through Girard's Reagent.

The green and environmentally friendly cardanol epoxy resin has a bright application prospect, but its insufficient thermal/mechanical properties seriously hinder its application. Adding nanoclay to polymer matrix is an effective method to enhance the thermal/mechanical properties of material, but the dispersion and compatibility of nanoclay in epoxy resin remain to be solved. In this work, active Girard's reagent clay (PG-clay) and non-active Girard's reagent clay (NG-clay) were prepared by using acethydrazide trimethylammonium chloride (Girard's reagent) as the modifier, and cardanol epoxy resin/G-clay nanocomposites were synthesized by the "clay slurry composite method". The results showed that both PG-clay and NG-clay were dispersed in the epoxy matrix in the form of random exfoliation/intercalation, which effectively improved the thermal/mechanical properties of the composites. Tg of the cardanol epoxy resin has raised from 19.8 °C to 38.1 °C (4 wt.% PG-clay). When the mass fraction of clay is 4%, the tensile strength of the non-reactive NG-clay increases by 128%, and the elongation at break also increases by 101%. Simultaneously, the active PG-clay can participate in the curing reaction of epoxy resin due to the amino group, forming a chemical bond between the clay layer and the resin matrix and establishing a strong interfacial force. The tensile strength of the composite is increased by 970%, and the elongation at break is also increased by 428%. This research demonstrates that the cardanol epoxy resin/G-clay nanocomposite stands as a highly promising candidate for bio-based epoxy resin materials.

Characterization of spironolactone and metabolites derivatized using Girard's reagent P using mass spectrometry and ion mobility spectrometry.

Spironolactone is a steroidal drug prescribed for a variety of medical conditions and is extensively metabolized quickly after administration. Measurement of spironolactone and its metabolites remains challenging using mass spectrometry (MS) due to in-source fragmentation and relatively poor ionization using electrospray ionization. Therefore, improved methods of measurements are needed, particularly in the case of small sample volumes. Girard's reagent P (GP) derivatization of spironolactone was employed to improve response and provide an MS-based solution to the measurement of spironolactone and its metabolites. We performed ultra-high-performance liquid chromatography-electrospray ionization-tandem mass spectrometry (UHPLC-ESI-MS/MS) and ion mobility spectrometry (IMS)-high-resolution mass spectrometry (HRMS) to fully characterize the GP derivatization products. Analytes were studied in positive ionization mode, and MS/MS was performed using nonresonance and resonance excitation collision-induced dissociation. We observed the successful GP derivatization of spironolactone and its metabolites using authentic chemical standards. A signal enhancement of 1-2 orders of magnitude was observed for GP-derivatized versions of spironolactone and its metabolites. Further, GP derivatization eliminated in-source fragmentation. Finally, we performed GP derivatization and ultra-high-performance liquid chromatography-high-resolution mass spectrometry (UHPLC-HRMS) in a small volume of murine serum (20 μL) from spironolactone-treated and control animals and observed multiple spironolactone metabolites only in the spironolactone-treated group. GP derivatization was proven to have advantageous mass spectral performance (e.g., limiting in-source fragmentation, enhancing signals, and eliminating isobaric analytes) for spironolactone and its metabolites. This work and the detailed characterization using ultra-high-performance liquid chromatography-high-resolution tandem mass spectrometry (UHPLC-HRMS/MS) and IMS serve as the foundation for future developments in reaction optimization and/or quantitative assay development.

O-GlycoIsoQuant: A Novel O-Glycome Quantitative Approach through Superbase Release and Isotopic Girard's P Labeling.

Quantitative glycosylation analysis serves as an effective tool for detecting changes in glycosylation patterns in cancer and various diseases. However, compared with N-glycans, O-glycans present challenges in both qualitative and quantitative mass spectrometry analysis due to their low abundance, ease of peeling, lack of a universal enzyme, and difficult accessibility. To address this challenge, we developed O-GlycoIsoQuant, a novel O-glycome quantitative approach utilizing superbase release and isotopic Girard's P labeling. This method facilitates rapid and efficient nonreducing β-elimination to dissociate O-glycans from proteins using the organic superbase, 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU), combined with light and heavy isotopic Girard's reagent P (GP) labeling for relative quantification of O-glycans by mass spectrometry. Employing this method, labeled O-glycans exhibit a double peak with a mass difference of 5 Da, suitable for stable relative quantification. The O-GlycoIsoQuant method is characterized by its high labeling efficiency, excellent reproducibility (CV < 20%), and good linearity (R2 > 0.99), across a dynamic range spanning a 100-fold range. This method was applied to various complex sample types, including human serum, porcine spermatozoa, human saliva, and urinary extracellular vesicles, detecting 33, 39, 49, and 37 O-glycans, respectively, thereby demonstrating its broad applicability.

Advanced Mg2+/Li+ separation nanofiltration membranes fabricated with Girard's reagent T based on functional end-capping strategy

Polyethyleneimine (PEI) nanofiltration (NF) membranes hold great application prospects in lithium extraction from salt lakes due to their high positive charge properties. However, the poor permeability of the membranes caused by the dense separation layer structure severely hinders their further application. Herein, a functional end-capping strategy was employed to address this problem by adding the effective end-capping reagent, Girard's Reagent T (GRT), to the PEI aqueous phase as the co-reaction reagent. Under the dual functions of the end-capping effect and the quaternary ammonium groups of GRT, the looseness and positive charge of the membrane were simultaneously optimized. After the modification of GRT, the looser structure of the PEI/GRT NF membrane improved its pure water flux (PWF) to 115 L m−2 h−1 at 6 bar, which was around 3.7 times higher than that of the original PEI NF membrane. Meanwhile, the enhanced positive charge (from −8 to 9 mV, pH = 7) of the membrane bottom surface allowed it to maintain the high rejection rate of MgCl2 at 97.2 %. Besides, the PEI/GRT NF membrane exhibited good Mg2+/Li+ selectivity (SMg2+/Li+ = 22.7, 2000 ppm, Mg2+/Li+ mass ratio: 20:1). Therefore, this study provides a simple and feasible strategy for the preparation of high-permeable PEI NF membranes with good Mg2+/Li+ separation performance.

Mobilized Electrospray Device for On-Tissue Chemical Derivatization in MALDI-MS Imaging.

Applying solutions of a matrix or derivatization agent via microdroplets is a common sample preparation technique for matrix-assisted laser desorption/ionization-mass spectrometry imaging (MALDI-MSI) experiments. Mobilized nebulizer sprayers are commonly used to create a homogeneous matrix or reagent layer across large surfaces. Electrospray devices have also been used to produce microdroplets for the same purpose but are rarely used for large tissues due to their immobility. Herein, we present a movable electrospray device that can be used for large tissue sample preparation through a simple modification to an automatic commercial nebulizer device. As demonstrated for on-tissue chemical derivatization (OTCD) with Girard's reagent T using a mimetic tissue model, the sprayer has the additional benefit of being able to investigate reaction acceleration in OTCD when comparing electrostatically charged spray to electrostatically neutral spray. Finally, MALDI-MSI of fatty aldehydes is successfully demonstrated in rat brain tissues using this device for both OTCD and matrix application.

Isomer-specific quantification of human milk oligosaccharides based on Girard reagent P-d0/d5 derivatization and trapped ion mobility spectrometry-mass spectrometry

Human milk oligosaccharides (HMOs), the third most abundant components in breastmilk, show high structural diversity with many isomers. Here, we proposed a trapped ion mobility spectrometry-mass spectrometry (TIMS-MS) strategy for the differentiating and isomer-specific quantification of HMOs combined with Girard reagent P-d0/d5 (GP-d0/d5) derivatization. Three functional HMO isomer pairs including LNT/LNnT, 3'-SL/6'-SL, and 2'-FL/3'-FL were investigated by the proposed method. The GP-derivatized HMO isomers showed enhanced ionization efficiency (8-fold) and achieved mobility separation with ΔCCS % ≥ 3.7% in TIMS-MS. With the GP-d5 derivatized HMOs as an internal standard, HMOs in real samples could be quantified by derivatization with GP-d0, and each isomeric species could be further determined based on their corresponding mobility peaks. The recoveries of spiked HMOs are obtained at 72.4 − 109%. Thus, an isomer-specific quantification strategy for HMO isomers was developed based on the GP-d0/d5 derivatization and TIMS-MS.

Functionalized cellulose microfibers as reductant agent to gold nanoparticles and its application on SERRS for sensitive detection of phthalocyanine dye

Cellulose-based materials have drawn great attention in the world due to its abundance, renewable source, biodegradability, and easy functionalization of structure. Herein, microfibrillar cationic dialdehyde cellulose (CMF) using Girard's reagent T was produced. The functional groups of CMF were employed to reduce gold(III) into nanoparticles (AuNPs) which remain anchored on the fibers, designing a never-before encountered hybrid CMF/AuNPs. The AuNPs are well-dispersed, presenting an average size of 25 nm. The CMF showed an excellent reducing agent without any other chemicals, providing a green synthesis route. The novel hybrid was applied as substrate for surface-enhanced resonance Raman scattering (SERRS) spectroscopy to nickel(II) tetrasulfonated phthalocyanine (NiTsPc) detection as a proof-of-principle. A detection limit (LOD) in order of 10-7 mol/L and a quantification limit (LOQ) of 3.58 × 10-7 mol/L for the band at 1359 cm-1 were found. The CMF/AuNPs held considerable promise as an effective SERRS substrate for sensitive detection and quantification of trace molecules.

Anticancer and Antiphytopathogenic Activity of Fluorinated Isatins and Their Water-Soluble Hydrazone Derivatives.

A series of new fluorinated 1-benzylisatins was synthesized in high yields via a simple one-pot procedure in order to explore the possible effect of ortho-fluoro (3a), chloro (3b), or bis-fluoro (3d) substitution on the biological activity of this pharmacophore. Furthermore, the new isatins could be converted into water-soluble isatin-3-hydrazones using their acid-catalyzed reaction with Girard's reagent P and its dimethyl analog. The cytotoxic action of these substances is associated with the induction of apoptosis caused by mitochondrial membrane dissipation and stimulated reactive oxygen species production in tumor cells. In addition, compounds 3a and 3b exhibit platelet antiaggregation activity at the level of acetylsalicylic acid, and the whole series of fluorine-containing isatins does not adversely affect the hemostasis system as a whole. Among the new water-soluble pyridinium isatin-3-acylhydrazones, compounds 7c and 5c,e exhibit the highest antagonistic effect against phytopathogens of bacterial and fungal origin and can be considered useful leads for combating plant diseases.

Improved analysis of derivatized steroid hormone isomers using ion mobility-mass spectrometry (IM-MS).

Over the last decade, applications of ion mobility-mass spectrometry (IM-MS) have exploded due primarily to the widespread commercialization of robust instrumentation from several vendors. Unfortunately, the modest resolving power of many of these platforms (~40-60) has precluded routine separation of constitutional and stereochemical isomers. While instrumentation advances have pushed resolving power to >150 in some cases, chemical approaches offer an alternative for increasing resolution with existing IM-MS instrumentation. Herein we explore the utility of two reactions, derivatization by Girard's reagents and 1,1-carbonyldiimidazole (CDI), for improving IM separation of steroid hormone isomers. These reactions are fast (≤30min), simple (requiring only basic lab equipment/expertise), and low-cost. Notably, these reactions are structurally selective in that they target carbonyl and hydroxyl groups, respectively, which are found in all naturally occurring steroids. Many steroid hormone isomers differ only in the number, location, and/or stereochemistry of these functional groups, allowing these reactions to "amplify" subtle structural differences and improve IM resolution. Our results show that resolution was significantly improved amongst CDI-derivatized isomer groups of hydroxyprogesterone (two-peak resolution of Rpp = 1.10 between 21-OHP and 11B-OHP), deoxycortisone (Rpp = 1.47 between 11-DHC and 21-DOC), and desoximetasone (Rpp = 1.98 between desoximetasone and fluocortolone). Moreover, characteristic collision cross section (DTCCSN2) measurements can be used to increase confidence in the identification of these compounds in complex biological mixtures. To demonstrate the feasibility of analyzing the derivatized steroids in complex biological matrixes, the reactions were performed following steroid extraction from urine and yielded similar results. Additionally, we applied a software-based approach (high-resolution demultiplexing) that further improved theresolving power (>150). Overall, our results suggest that targeted derivatization reactions coupled with IM-MS can significantly improve the resolution of challenging isomer groups, allowing for more accurate and efficient analysis of complex mixtures.

Dual-crosslinked starch/carboxymethyl cellulose blend film with ion-responsive dissolution properties

While the ability of quickly vanishing in water has made starch-based plastics a potential solution to the current marine plastic issue caused by discarded single-use plastics, this ability also translates into lack of water resistance in daily scenario. Here, we aim to improve the water resistance of starch-based blend films in daily scenarios while allowing them to disintegrate and vanish rapidly in marine environments via the introduction of ionic crosslinks. A dialdehyde starch (DAS)/carboxymethyl cellulose (CMC) blend film is prepared via a modified solution casting process, during which DAS is gradually rendered cationic by a cationizing reagent, Girard's reagent T, and interacts with CMC to form ionic crosslinks. Meanwhile, the aldehyde groups on DAS also form acetal bonds with the -OH groups on both DAS and CMC, which further increases the wet strength. In solutions of low ionic strength encountered in daily life, such as freshwater, the film remains stable for both types of crosslinks. In high-ionic-strength solutions, such as seawater, the film swells rapidly and disintegrates owing to the cleavage of ionic crosslinks. This study demonstrated ionic crosslink could be a potential solution for balancing the protection of marine ecosystem and ease of use of starch-based blend films, which is essential to the development of future marine ecosystem-friendly single-use plastics.

Isotope-coded derivatization with designed Girard-type reagent as charged isobaric mass tags for non-targeted profiling and discovery of natural aldehydes by liquid chromatography-tandem mass spectrometry

Aldehyde-containing metabolites are reactive electrophiles that have attracted extensive attention due to their widespread occurrence in organisms and natural foods. Herein we described a newly-designed Girard's reagent, 1-(4-hydrazinyl-4-oxobutyl)pyridin-1-ium bromide (HBP), as charged tandem mass (MS/MS) tags to facilitate selective capture, sensitive detection and semi-targeted discovery of aldehyde metabolites via hydrazone formation. After HBP labeling, the detection signals of the test aldehydes were increased by 21–2856 times, with the limits of detection were 2.5–7 nM. Upon isotope-coded derivatization with a pair of labeling reagents, HBP-d0 and its deuterium-labeled counterpart HBP-d5, the aldehyde analytes were converted to hydrazone derivatives, which generated characteristic neutral fragments of 79 Da and 84 Da, respectively. The isobaric HBP-d0/HBP-d5 labeling based LC-MS/MS method was validated by relative quantification of human urinary aldehydes (slope=0.999, R2 > 0.99, RSDs ≤ 8.5%) and discrimination analysis between diabetic and control samples. The unique isotopic doubles (Δm/z = 5 Da) by dual neutral loss scanning (dNLS) provided a generic reactivity-based screening strategy that allowed non-targeted profiling and identification of endogenous aldehydes even amidst noisy data. The LC-dNLS-MS/MS screening of cinnamon extracts led to finding 61 possible natural aldehydes and guided discovery of 10 previously undetected congeners in this medicinal plant.

LC-MS/(MS) confirmatory doping control analysis of intact phase II metabolites of methenolone and mesterolone after Girard's Reagent T derivatization.

In the present study, the application and evaluation of Girard's Reagent T (GRT) derivatization for the simultaneous detection and significantly important identification of different phase II methenolone and mesterolone metabolites by LC-MS/(MS) are presented. For the LC-MS analysis of target analytes two complementary isolation methods were developed; a derivatization and shoot method in which native urine is diluted with derivatization reagent and is injected directly to LC-MS and a liquid-liquid extraction method, using ethyl acetate at pH 4.5, for the effective isolation of both sulfate and glucuronide metabolites of the named steroids as well as of their free counterparts. For the evaluation of the proposed protocols, urine samples from methenolone and mesterolone excretion studies were analyzed against at least one sample from a different excretion study. Retention times, along with product ion ratios, were evaluated according to the WADA TD2021IDCR requirements, in order to determine maximum detection and identification time windows for each metabolite. Established identification windows obtained after LC-MS/(MS) analysis were further compared with those obtained after GC-MS/(MS) analysis of the same samples from the same excretion studies, for the most common analytes monitored by GC-MS/(MS). Full validation was performed for the developed derivatization and shoot method for the identification of methenolone metabolite, 3α-hydroxy-1-methylen-5α-androstan-17-one-3-glucuronide (mth3). Overall, the GRT derivatization presented herein offers a tool for the simultaneous sensitive detection of free, intact glucuronide and sulfate metabolites by LC-MS/(MS) that enhance significantly the detection and identification time windows of specific methenolone and mesterolone metabolites for doping control analysis.

A Comparative Study of Mechanism and Performance of Anionic and Cationic Dialdehyde Nanocelluloses for Dye Adsorption and Separation.

In this study, anionic dialdehyde cellulose (DAC) and cationic dialdehyde cellulose (c-DAC) nanofibrous adsorbents were prepared via a two-step reaction from bamboo pulp, using sodium periodate and Girard's reagent T as oxidizing and cationizing agents, respectively. The performance of DAC and c-DAC for selective dye adsorption and separation was evaluated by six different organic dyes (with varying charge properties) and certain binary mixtures. Both adsorbents could remove the dyes but with different capability, where DAC exhibited high adsorption efficiency against cationic dyes (e.g., the maximum adsorption capacity for Bismarck brown Y was 552.1 mg/g) and c-DAC exhibited high adsorption efficiency against anionic dyes (e.g., the maximum adsorption capacity for Congo red was 540.3 mg/g). To investigate the adsorption mechanism for these adsorbents, effects of contact time, initial pH value, initial dye concentration, and ionic strength on the adsorption activity against Congo red were investigated. The adsorption equilibrium data of DAC were found to fit best with the Langmuir isotherm model, whereas that of c-DAC were found to fit best with the Freundlich model. Both DAC and c-DAC adsorption kinetic data could be described by the pseudo-second-order kinetic model, and these adsorbents possessed stable adsorption efficiency in the pH range of 4-10. Furthermore, their dye adsorption capabilities were found to increase with increasing ionic strength (salt concentration). The distinctive complementary features of DAC and c-DAC will allow them to remove a wide range of organic dyes from industrial wastewater.

High-resolution ion mobility spectrometry-mass spectrometry for isomeric separation of prostanoids after Girard's reagent T derivatization.

Isomeric separation of prostanoids is often a challenge and requires chromatography and time-consuming sample preparation. Multiple prostanoid isomers have distinct in vivo functions crucial for understanding the inflammation process, including prostaglandins E2 (PGE2 ) and D2 (PGD2 ). High-resolution ion mobility spectrometry (IMS) based on linear ion transport in low-to-moderate electric fields and nonlinear ion transport in strong electric fields emerges as a broad approach for rapid separations prior to mass spectrometry. Derivatization with Girard's reagent T (GT) was used to overcome inefficient ionization of prostanoids in negative ionization mode due to poor deprotonation of the carboxylic acid group. Three high-resolution IMS techniques, namely linear cyclic IMS, linear trapped IMS, and nonlinear high-field asymmetric waveform IMS, were compared for the isomeric separation and endogenous detection of prostanoids present in intestinal tissue. Direct infusion of GT-derivatized prostanoids proved to increase the ionization efficiency in positive ionization mode by a factor of >10, which enabled detection of these molecules in endogenous concentration levels. The high-resolution IMS comparison revealed its potential for rapid isomeric analysis of biologically relevant prostanoids. Strengths and weaknesses of both linear and nonlinear IMS are discussed. Endogenous prostanoid detection in intestinal tissue extracts demonstrated the applicability of our approach in biomedical research. The applied derivatization strategy offers high sensitivity and improved stereoisomeric separation for screening of complex biological systems. The high-resolution IMS comparison indicated that the best sensitivity and resolution are achieved by linear and nonlinear IMS, respectively.

Sensitive HPLC-DMS/MS/MS method coupled with dispersive magnetic solid phase extraction followed by in situ derivatization for the simultaneous determination of multiplexing androgens and 17-hydroxyprogesterone in human serum and its application to patients with polycystic ovarian syndrome

Background and aimsAndrogens play important roles in polycystic ovarian syndrome (PCOS). However, measures of androgens based on mass spectrometry (MS) remain complex due to endogenous inferences of isomers or compounds with similar structures. Lack of sensitivity can also affect the accurate quantification of androgens, especially for very low level of 11-oxygenated androgens. Materials and methodsWe developed a fast and sensitive high-performance liquid chromatography-differential mobility spectrometry tandem mass spectrometry (HPLC-DMS/MS/MS) method for the simultaneous determination of seven androgens and 17-hydroxyprogesterone. Dispersive magnetic solid phase extraction (DMSPE) was conducted with core–shell structured nanoparticles of magnetic graphene oxide (Fe3O4@GO). In situ derivatization was performed using Girard's Reagent P. ResultsLinear ranges of the eight analytes were set in terms of clinical use. Intra- and inter-run precisions were < 16.7 % and 12.9 % for all the analytes and relative error was − 14.7–13.3 % and − 9.3–11.0 %, respectively. Extraction recoveries were 54.0–92.7 % for different analytes. The method was validated and was applied to assay 432 clinical samples. ConclusionThe developed method is green, fast, sensitive and accurate for the determination of endogenous androgens. It can be readily implemented in medical laboratories to provide superior analytical performance over the traditional electrochemiluminescence immunoassay method.

A comprehensive UHPLC-MS/MS method for the analysis of endogenous and exogenous steroids in serum for anti-doping purposes.

In the context of steroid analyses, the use of blood could represent a valuable complement to urine. While the blood steroid profile is currently being established to aid unveiling testosterone (T) doping, this matrix is also well suited for detection of exogenous anabolic steroids and steroid esters. In this study, a method to determine a simplified blood steroid profile in combination with the direct detection of exogenous anabolic steroids and steroid esters using just one serum aliquot was developed to obtain a comprehensive analytical workflow. Following the first chromatographic analysis of endogenous and exogenous steroids, samples were derivatised with Girard's reagent T (GT) to improve the ionisation of steroid esters and re-injected. The quantitative performance for T, androstenedione (A4) and 5α-dihydrotestosterone (DHT) was evaluated and the method was validated for qualitative analysis of exogenous analogues with estimated limits of detection (LOD) between 50 and 500 pg/ml. To demonstrate the applicability of the method, samples collected from a clinical study with an oral administration of testosterone undecanoate (TU) to 19 male volunteers were then analysed. The individual serum steroid profiles with the endogenous markers T, A4 and DHT were established as well as the concentrations of TU. TU was detected in all 19 volunteers up to 24 h, while DHT represented the most promising biomarker in endogenous steroid profile for the detection of oral TU administration. These results showed that the selected approach to combine exogenous and endogenous steroid analysis has the potential to strengthen T doping detection in the future.

Development and application of a sensitive phosphonium-hydrazide oligosaccharide labelling reagent in capillary electrophoresis- electrospray ionization- mass spectrometry

Glycosylation is one of the most ubiquitous post-translational modifications (PTM) of proteins. Although the ionization efficiency of native glycans is fairly low, with the assistance of chemical derivation strategies, mass spectrometry (MS) has been extensively used in glycomics because of its high sensitivity, accuracy, and speed. In this study, a novel glycan labelling reagent, (4-hydrazidebutyl) triphenylphosphonium bromide (P4HZD), with a permanent positive charge was developed. The comprehensive capabilities of P4HZD for MS analysis of oligosaccharides were evaluated in detail using maltodextrin as a standard. This labelling reagent can be used in common biological MS techniques such as matrix-assisted laser desorption ionization (MALDI) and electrospray ionization (ESI) mass spectrometry. The MS signal intensity of maltodextrin species could be enhanced up to 96-fold in MALDI-MS by labelling with P4HZD, making P4HZD favorable for MALDI-MS-based high-throughput screening of oligosaccharides. Moreover, P4HZD-labelled oligosaccharides with a degree of polymerization (DP) from 1 to 18 could be separated and analysed by capillary electrophoresis (CE) combined with positive ion mode ESI-MS. In comparison with a commercialized oligosaccharide tag, Girard's reagent P (GirP), P4HZD was more effective for enhancing the signal of oligosaccharides in the middle or higher mass range using both ESI and MALDI ion sources. Two biologics, immunoglobulin G 2 (IgG 2) and fusion protein (FP), were chosen as model complex biological samples to test the efficacy of detection and separation of oligosaccharides by MALDI-MS and CE-ESI-MS analysis with P4HZD labelling. The results indicated that P4HZD is a promising labelling reagent for the detection of oligosaccharides in complex biological samples. The tandem workflow combines the strengths of MALDI-MS and CE-ESI-MS to fulfil the analytical demands of high-throughput screening, while affording good separation.

Molecular characterization of carbonyl compounds in atmospheric fine particulate matters (PM2.5) in Beijing by derivatization with Girard's reagent T combined with positive-ion ESI Orbitrap MS

Carbonyl compounds in aerosols endanger human health, affect atmospheric light absorption and cloud condensation nuclei activity, and are important precursors of secondary organic aerosols, but their composition is poorly understood. In the present study, we developed a new analytical method to characterize carbonyl compounds in PM2.5 (particles with aerodynamic diameter ≤ 2.5 μm) by chemical derivatization with Girard's reagent T combined with positive-ion ESI high resolution-mass spectrometry (HR-MS). Girard's reagent T selectively labels carbonyl compounds, and HR-MS provides accurate elemental composition of derivatives. This method realized the comprehensive molecular characterization of carbonyl compounds in PM2.5. Thousands of carbonyl formulas (2330) were identified, including aliphatic carbonyls and a series of aromatic carbonyls. This method was further applied to the quantification of carbonyl compounds in PM2.5 samples collected in summer and winter from 2016 to 2017. In winter, carbonyl compounds had the highest contribution to organic matter (10%) and PM2.5 (4%), respectively, and the concentration of carbonyls showed obvious seasonal variation characteristics: 2.04 μg/m3 in winter and 0.35 μg/m3 in summer. The detailed characterization of the molecular composition of carbonyl compounds in PM2.5 provides basic data for further evaluating its impact on the climate effect of organic aerosols.