Rationale. Data are required for SIFT-MS analysis of per- and poly-fluoroalkyl substances (PFAS) that are persistent in the environment and cause adverse health effects. Specifically, the rate coefficients and product ion branching ratios of the reactions of H 3O +, NO +, O 2 +•, O -•, OH -, O 2 -•, NO 2 -, and NO 3 - with PFAS vapours are needed. Methods The dual polarity SIFT-MS instrument (Voice200) was used to generate these 8 reagent ions and inject them into the flow tube with N 2 carrier gas at a temperature of 393 K. Vapours of pentafluoropropionic acid, heptafluorobutyric acid, nonafluoro-1-hexanol, perfluoro-2-methyl-2-pentene, perfluorohexanoic acid, perfluoro(2-methyl-3-oxahexanoic) acid, tridecafluoro-1-octanol, and nonafluorobutane-1-sulfonic acid were introduced in dry and humid air. Full-scan mass spectra were collected for all reagents at variable PFAS concentrations and analysed numerically. Results Rate coefficients were determined for 64 reactions, for which 55 positive and 71 negative product ions were identified. The branching ratios for the primary reaction channels were extracted from the data, and the secondary chemistry with H 2O molecules was qualitatively assessed. The thermochemical data were calculated for the H 3O + reactions using Density Functional Theory (DFT). Conclusions An important observation is that secondary reactions with water molecules remove the positive product ions, making them unsuitable for practical SIFT-MS analysis of PFAS vapours. In contrast, most negative reaction product ions are not significantly affected by humidity and are thus preferred for the SIFT-MS analyses of PFAS substances in various gaseous matrices.

Alkali metals have been used to degrade SF 6 in liquid ammonia. The products include metal fluorides. In this study, we reacted K − and Ag − with SF 6 in a triple quadrupole mass spectrometer. The atomic metal anions were formed by in-source collision-induced dissociation (CID) of their respective oxalate salts as previously described by our group. The only two reaction products observed were SF 6 − and SF 5 −. At low collision energy, the latter was deduced to be formed via an abstraction by the metal of F from SF 6 − formed by electron transfer in the encounter complex between the metal anion and neutral SF 6. As the collision energy was increased, there was evidence of a CID contribution to SF 5 − directly from SF 6 −.

The unimolecular reactions of protonated α- and β-pinene ions were explored with a combination of collision-induced dissociation tandem mass spectrometry and theory. The two main dissociation reactions in each ion lead to the losses of neutral propene and isobutene. The difference observed between the two ions is a greater relative abundance of propene loss in the case of protonated a-pinene. Both ions were found to dissociate over the same minimum energy reaction pathway, the only difference being the site of initial protonation in the two ions. a-Pinene preferentially protonates at the bridging carbon, while b-pinene can only significantly protonate at the exocyclic double bond. This leads to a lower appearance energy for loss of isobutene, and thus relatively greater m/z 81 fragment ion abundance for b-pinene.

RATIONALE: Understanding plant defense mechanisms against pathogens is critical for agricultural productivity and crop protection. This study focuses on the quantification of camalexin and scopoletin, essential phytoalexins in Arabidopsis thaliana, using advanced mass spectrometry techniques. Accurate measurement of these compounds can provide insights into plant resistance and support agricultural research. METHODS: Camalexin and scopoletin were quantified using matrix-assisted laser desorption ionization high-resolution mass spectrometry (MALDI-HRMS). The matrix and solvent conditions were optimized to enhance sensitivity and accuracy. MS/MS experiments confirmed the identification with high mass accuracy (mass error < 5 ppm). RESULTS: The method demonstrated high linearity for scopoletin (R 2 = 0.9992) and camalexin (R 2 = 0.9987) over concentration ranges of 0.16-5 µM and 0.31-5 µM, respectively. The limits of detection (LOD) were 0.16 µM for camalexin and 0.04 µM for scopoletin, while the limits of quantification (LOQ) were 0.31 µM for camalexin and 0.16 µM for scopoletin. The average relative standard deviation was 1.43% for scopoletin and 2.46% for camalexin, with average relative errors of 3.91% and 4.11%, respectively. CONCLUSIONS: This study presents a precise, and accurate method for the quantification of key phytoalexins in Arabidopsis thaliana. The developed MALDI-HRMS approach significantly contributes to the understanding of plant defense mechanisms and offers potential applications in agricultural and biotechnological research.

Rationale: These experiments were conducted to measure the diversity of organo-U(IV) and U(III) ions created using multidimensional tandem MS and collision-induced dissociation of halogen-substituted U VIO 2-phenide complexes [UO 2(C 6H 3FX)] +, X = Cl, Br, or I. Methods: Samples of UO 2(O 2C-C 6H 3FX) 2 were prepared by digesting UO 3 with appropriate halogen-substituted carboxylic acids in deionized water. Solutions for ESI were created by diluting the digested sample in 50:50 H 2O/CH 3OH. Precursor ions for multiple-stage tandem MS were generated by electrospray ionization (ESI). Multiple-stage collision-induced dissociation (He collision gas) in a linear quadrupole ion trap mass spectrometer was used to prepare species such as [U IVFX(C≡CH)] + and U IIIF(C≡CH)] + for subsequent study of ion-molecule reactions with adventitious neutrals in the ion trap. Results: Multiple-stage CID of the [UO 2(C 6H 3FX)] +, X= Cl, Br, or I, complexes caused removal of both “yl” oxo ligands from of the UO 2 2+ moiety to create ions such as [U IVFX(C≡CH)] + and [U IIIFX] +. For [U IVFXC≡CH] + and [U IIIFC≡CH] + products, hydrolysis to generate [U IVFX(OH)] + and [U IIIF(OH)] +, with concomitant loss of HC≡CH, was observed. When X = Cl and Br, elimination of HX was competitive with loss of HC≡CH. CID of [UO 2(C 6H 3FBr)] + and [UO 2(C 6H 3FI)] + caused reductive elimination of the respective halogen radicals to generate interesting organo-U(III) species such as [U IIIF(C≡CH)] + and [U IIIC 2] +. Conclusions: The use of “preparative” tandem mass spectrometry and a suite of halogen substituted benzoic acid ligands can be used to remove both oxo ligands of UO 2 2+ and generate a group of homologous organo-U(IV) and organo-U(III) ions for studies of intrinsic reactivity.

The analysis of natural abundance isotopes in biogenic N 2O molecules can give precious information such as the nature of their precursor. However, many uncertainties exist and further validations are necessary to confirm this method as a reliable tracer of biogeochemical cycles. In particular, current methodologies (such as the isotopocule map approach) can only estimate the combined contributions of several processes at once. In this study, we aimed to develop a new methodology capable of individually discriminating the main sources of N 2O production in soil by combining natural abundance isotopes with the use of a 15N tracer ( 15N Gas Flux method). To achieve this, we conducted parallel laboratory incubations of an agricultural soil, during which we optimized the denitrification conditions through increase of moisture and amendment of nitrate; where this nitrate was either labelled or unlabeled with 15N atoms. A new linear system combined with Monte Carlo simulation enabled the determination of N 2O source partitioning, where bacterial denitrification was identified as the dominant process (87.6%), compared to fungal denitrification (9.4%), nitrification (1.5%) and nitrifier denitrification (1.6%). This new system has been compared to a recently developed stable isotope modelling tool applying Bayesian statistics (FRAME). The results agreed generally well at the exception of lower bacterial denitrification (80%) and higher nitrifier-denitrification (9%) contributions found with the FRAME model. This new approach provides a perspective for a wider application, potentially enabling the source partitioning of nitrous oxide emissions in agroecosystems.

Rationale: Erigeron breviscapus （EB）and Erigeron multiradiatus (EM) are the two species of the genus Erigeron (Asteraceae) with extremely close genetic relationships. They were used as the same “meiduoluomi” for the treatment of plague and epidemics in traditional Tibetan medicine. But in traditional Chinese medicine, only EB is used for treatment of cerebrovascular obstruction, hemiplegia due to stroke, coronary artery obstruction, chest congestion, angina pectoris. These two Erigeron species show different effects in different traditional medicines system. Therefore, analyzing the chemical compositions of two species will not only enhance comprehension of their medicinal properties, but also foster the advancement and exploration of novel applications. However, to date, there has been no comprehensive and detailed investigation comparing the constituents of EB and EM. Methods: A methodology for rapid identification of chemical profiles from two Erigeron species was devised through the integration of UHPLC-QTOF-MS/MS and multivariate statistical analysis. Additionally, a UHPLC-PDA method was established to precisely quantify of 11 components. Results: A total of 58 constituents comprising flavonoids, phenolics acids, saponin and long chain fatty acids were elucidated. Thirteen compounds were identified as potential differentiators in chemical profiles among the two Erigeron species. For quantitative assessment, 11 bioactive compounds were simultaneously quantified across 49 batches of Erigeron species samples utilizing UHPLC-PAD with wavelengths of 325 nm, 254 nm, and 266 nm. The method demonstrated excellent precision, linearity, accuracy, repeatability, stability, and recovery. Conclusions: The findings from this study will serve as a reference for quality control, functional activity exploration, and improved clinical application based on the ingredient profiles of the two species. Furthermore, this inaugural investigation into the ingredient profiles of these two species will enhance the potential and optimal utilization of both EB and EM resources.

Rationale: Flavonoid C-glycosides have a wide range of pharmacological activities. However, there are few mass spectrometric research on C,O-disaccharide flavonoid C-glycosides and di-C,O-saccharide flavonoid C-glycosides. Their fragmentation pattern and differences have not been reported, and the fragment ion library is incomplete. Therefore, it was essential to elucidate the fragmentation patterns of disaccharide flavonoid C-glycosides, which is described in this study. Methods: Four disaccharide flavonoid C-glycosides such as vitexin-4″- O-glucoside were analyzed by ultra performance liquid chromatography-triple quadrupole tandem mass spectrometer (UPLC-MS/MS) in both positive and negative ion modes. each ion and its proposed fragmentation pathways of the four disaccharide flavonoid C-glycosides were analyzed comprehensively. Finally, Ultra-high performance liquid chromatography-quadrupole time-of-flight mass spectrometry (UPLC-Q-TOF-MS/MS) and the established fragmentation patterns have been used to identify disaccharide flavonoid C-glycosides in Odontosoria Chinensis. Results: The fragmentation pathways of C,O-disaccharide flavonoid C-glycosides and di-C,O-saccharide flavonoid C-glycosides. are similar. they both have the mass spectrometric characteristics of O-glycoside and C-glycoside. Fragment ions after mixed pathways of neutral fragments such as saccharide ring fragment, O-glycosides, H 2O and CH 2O detraction appeared in both types of flavonoid C-glycosides, but their relative abundances are significantly different. According to the established fragmentation patterns, di-C,O-saccharide flavonoid glycosides were also found in Odontosoria Chinensis. Conclusion: The fragment ions of m/z 431, 413, 341, 311, 293, 282 in negative ion mode and m/z 293, 282, 577, 559, 541, 523, 529 and 499 in positive ion mode can serves as the main characteristics for identifying C,O-disaccharide flavonoid C-glycosides and di-C,O-saccharide flavonoid C-glycosides.

During our careers, we met Jean-François Muller essentially in the context of scientific meetings and PhD examination panels, in relation with the use of Fourier transform ion cyclotron resonance (FT-ICR) mass spectrometry. However, one of us (PCM) had also the opportunity to meet him in a less well-known aspect of his implication in societal activities related to the monitoring of air quality. In this recollection of Jean-François Muller, we would like to recall how his science has also served societal causes.

Aim: Cupressus torulosa (family Cupressaceae), widely distributed in the north western Himalayan region of India, is a coniferous aromatic tree with various traditional uses of its aerial parts. Its needles have been used for anti-inflammatory, anticonvulsant, antimicrobial, and wound-healing properties. Antioxidants are pivotal in mitigating oxidative stress, a contributing factor to various diseases and aging processes. Employing a diverse array of analytical techniques, ranging from TPC, TFC to in vitro, in vivo assays and UPLC-QTOF-MS the research assesses the antioxidant potential of the Cupressus torulosa. Mаteriаls аnd methods: Employing а diverse аrrаy of аnаlyticаl techniques, rаnging from TPC, TFC to in vitro, in vivo аnd ex- vivo аssаys аnd UPLC-QTOF-MS the reseаrch аssesses the аntioxidаnt potentiаl of the plаnt. The initiаl screenings reveаl promising аntioxidаnt properties of the extrаct, with vаlues of 55.28± 57.07*,52.27± 19.50 in SGOT, SGPT (IU/L) аssаys respectively when compаred to positive control glibenclаmide. With subsequent frаctionаtion into butаnol аnd ethyl аcetаte frаctions. The ethyl аcetаte frаction exhibited pаrticulаrly notаble аctivity with lower vаlue of EC50 vаlue of 85.6 μg/mL in DPPH аssаy offering insights into the mechаnisms аnd effectiveness of these compounds in scаvenging free rаdicаls аnd mitigаting oxidаtive dаmаge. Results аnd Conclusion: Moreover, the chemicаl composition of аctive frаctions undergoes chаrаcterizаtion utilizing UHPLC-QTOF-MS, fаcilitаting the identificаtion of 34 metаbolites identified in negаtive mode with 10 key аntioxidаnt compounds аnd the elucidаtion of their frаgmentаtion pаtterns. These findings underscore the potentiаl of C. torulosа аs а bountiful reservoir of bioаctive аntioxidаnts, emphаsizing their significаnce in phаrmаceuticаl аnd nutrаceuticаl аpplicаtions. This reseаrch mаkes а substаntiаl contribution towаrds identifying potent аntioxidаnt compounds, emphаsizing the need for future efforts in isolаting аnd clinicаlly testing them. It enhаnces our understаnding of nаturаl аntioxidаnts аnd their criticаl role in enhаncing heаlth аnd аddressing oxidаtive-relаted conditions.

Gas chromatography-mass spectrometry (GC-MS) is a cornerstone technique for analyses of semi-volatile compounds, constantly evolving to meet new challenges. The adoption of Time-of-flight mass spectrometers (TOF MS) has enhanced GC-MS with faster spectral acquisition and broader mass coverage, enabling rapid GC separations and even faster two-dimensional GCxGC analyses. Multi-reflecting TOF MS (MRT) further improves resolution compared to traditional TOF MS, facilitating the detection of minor analytes within complex matrices. This paper presents a significant improvement in MRT sensitivity and dynamic range achieved through a strong ion beam compression within the ion guide and the use of a conventionally oriented orthogonal accelerator. Sensitivity is improved to 100,000 ion/pg at a resolution of R=25,000, enabling the detection of low fg analyte quantities within 3 μg of matrix at 10 ng/s matrix fluxes. The demonstrated linear dynamic range exceeding 6 orders of magnitude potentially enables even deeper exploration of complex mixtures, which is crucial for ultra-trace analyses and metabolomic studies.

not-yet-known not-yet-known not-yet-known unknown An ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) method was developed for the simultaneous determination of three ephedrine psychoactive substances in water. By optimizing chromatography conditions, mass spectrometry parameters, and solid-phase extraction (SPE) conditions (including the SPE column, sample pH, washing, and elution), the optimal treatment conditions were determined. Poly-Sery MCX was selected as the extraction column, with samples loaded at pH 3. A 4 mL solution of 2% formic acid in water was used as the eluent, and a 5 mL solution of 5% ammonia in acetonitrile was used to elute the target compounds. The best results were obtained when the residue was redissolved in acetonitrile after nitrogen evaporation. The method exhibited a good linear relationship in the range of 0-50.00 μg/L, with determination coefficients (R 2) greater than 0.9990. The detection limit and quantitation limit were 0.05-0.10 μg/L and 0.20-0.50 μg/L, respectively. Recovery rates of the target compounds in blank sewage at three different concentration levels ranged from 92.37% to 106.31%, with relative standard deviations (RSD) of 0.77-4.83% (n=7). This method has been successfully applied to the analysis of surface water and domestic sewage, demonstrating stable treatment effects and practical significance for detecting ephedrine psychoactive substances in water.

We describe a workshop which prompts chemistry students in the final two years of secondary school to apply their understanding of modern analytical chemistry techniques to a ‘real world’ example. The scenario used is that of a forensic science laboratory that has been asked to determine the structure of an illicit compound, Revisomed (methamphetamine) being sold as a revision aid, and seized by police. Over the course of an hour, the students use a combination of infrared (IR) spectroscopy, liquid chromatography (LC), high resolution mass spectrometry (MS) and nuclear magnetic resonance (NMR) spectroscopy data to determine the structure of Revisomed from first principles. The bulk of the workshop is spent reviewing MS data and using m/z, the isotope pattern, elemental composition and product ion data to reach three plausible isomeric structures for Revisomed which are then distinguished by NMR spectroscopy. More broadly, the workshop focusses on the use of the scientific method and the concept that ‘no ideas are bad’ when exploring hypotheses. We describe the structure of the workshop, and our experience delivering it to a local academy over the last 9 years.

Rationale: Helium (He) and energy shortages have dramatically increased prices and reduced their availability of these commodities. The use of three combustion reactions per acquisition of carbon and nitrogen isotope ratios saved 50% He and energy used in elemental analysis/isotope ratio mass spectrometry (EA/IRMS). This approach should be tested for sulfur isotope analyses. Mathods: A method was developed to measure sulfur isotope ratios ( d 34S values) in the SO 2 produced from three sequential combustion reactions in a single EA/IRMS acquisition. The combustion cycles involved capsules of the same or different materials. Two other developments are presented: a system for simultaneous extraction of chromium-reducible sulfur from four sediments or rock samples and the connections between the SO 2 reference gas and nitrogen cylinders for purging residual gases at the end of the EA/IRMS sequences. Results: The 3×EA/IRMS- d 34S method was validated with replicate analyses of international reference materials and laboratory standards with a wide range of mineralogical compositions and d 34S values. It was used for d 34S measurements of CRS-pyrites from Archean black shales and Swiss lake sediments. The accuracy and precision of the 3×EA/IRMS values were essentially matched those obtained by conventional EA/IRMS, with good agreement between the mean ± SD values and the recommended values and their Conclusions: Compared with the conventional EA/IRMS method. the proposed method provides accurate and precise sulfur isotope compositions of sulfate and sulfide samples while saving approximately 50% of the He, energy, SO 2 reference gas, O 2, and analysis time and cost. Notably, 3×EA/IRMS provided two d 34S values unaffected by potential memory effects.

Rationale: Wildlife scientists are quantifying steroid hormones in a growing number of tissue types and employing novel methods which must undergo validation before application. This study tested the accuracy and precision of liquid chromatography-tandem mass spectrometry (LC-MS/MS) methods for use on blubber samples from short-finned pilot whales ( Globicephala macrorhynchus). We expanded upon a method for corticosteroid quantification by increasing the number of analytes and optimizing internal standards application. Methods: We optimized a method for the quantification of seven steroid hormones using LC-MS/MS with a C18 column. We assessed the accuracy and precision of this updated C18 method and an existing Biphenyl method for use with short-finned pilot whale blubber tissue by conducting a spike-recovery experiment and calculating percent recovery and relative standard deviation (RSD) for each analyte. To explore the potential for running this method more cost-effectively with fewer matched internal standards (IS), we compared the performance of multiple internal standards for each analyte. Results: The C18 method produced reliable quantitation for the seven target adrenal steroids. The measurement of all 11 adrenal and gonadal analytes was both accurate and precise, with percent recoveries between 82 % to 110 % and RSDs below 10 %. IS comparisons showed 10 of 11 analytes could be calculated accurately and precisely with at least one of the IS substitutes. Though many internal standard substitutions met percent recovery and RSD requirements, some of these substitutions significantly altered the analyte concentrations calculated. Discussion: The methods developed and tested in this study provide reliable detection and quantification of 11 steroid hormones, including DHEA, which has not been previously quantified in blubber. These methods can be used for more comprehensive assessments of adrenal and gonadal steroid hormones from whales. Laboratories can reduce costs through IS substitution but should consider how these substitutions might affect results.

Recent data suggest that passive smoking has a risk comparable to active smoking. Passive smoking is considered dangerous in children and is suspected as a cause of asthma. However, some reports are opposing such claims, indicating the need for solid results and large-scale studies. This scientific work aims to develop a method for the determination of nicotine (NCOT) and major nicotine’s metabolite cotinine (COT) in urine samples, using gas chromatography-mass spectrometry (GC-MS). For sample preparation, liquid-liquid extraction was applied after an optimization study with different extraction media. Eventually, 1 mL of dichloromethane was selected for the extraction of 0.5 mL of urine. Suitable chromatographic conditions were found for the rapid and accurate determination of NCOT and COT. The method was validated to meet the criteria for application in a bioanalytical laboratory. Injection of 2 μL was done in GC/MS, and SIM (selected ion monitoring) analysis was performed with the following ions (m/z): 162 (quantifier ion) and 84, 133, 161 qualifier ions for NCOT, and 176 (quantifier ion) and 98, 118, 119, 147 qualifier ions for COT. Nicotine-D4 (NCOT-D4) and cotinine-D3 (COT-D3) and were used as internal standards with quantifier ions 101 and 166, respectively. The retention time (Rt) for NCOT was 7.557 min and for COT 9.743 min. The duration of the GC-MS analysis was 20 minutes. The method showed a linear dynamic range from 0.5 to 50 ng/mL. Finally, the method was applied to the analysis of sixty clinical pediatric samples obtained from Aristotle University’s pediatric clinic to check for possible exposure to smoke.

Rationale: The Δ 36S standard deviation (SD) measured in a conventional isotope-ratio mass spectrometer (IRMS) such as MAT 253 is at c.a. 0.1‰ to 0.3‰. At this precision, it is difficult to resolve the origin of non-mass-dependent sulfur (NMD-S) isotope fractionation in the tropospheric sulfate aerosol and in Martian meteorites or small deviations from the canonical mass-dependent fractionation laws. Interfering ions (originated from fluorination and/or mass spectrometer ion source itself) with m/z at 131 of 36SF 5 + by the community as the cause of the poor precision, but the exact ion species has not been identified or confirmed. Methods: Here we examined the potential interfering ions by using the Thermo Scientific MAT 253 Ultra, a high-resolution (mass resolving powers up to 40,000) stable isotope-ratio mass spectrometer, to measure the SF 6 working gas and SF 6 gases converted from IAEA-S1 Ag 2S reference materials via a fluorination system. Results: We found that there is a resolvable peak to the right of the 36SF 5 + peak for both the SF 6 working gas and SF 6 generated by the fluorination system. The peak is identified as the 12C 3F 5 + ion, generated inside the instrument during the ionization process. By minimizing the presence of carbon-bearing compounds (e.g., organic matter in sample or helium gas, glue or o-ring in sample tubes, or carbon-bearing gases inside the mass spectrometer), we were able to achieve a Δ 36S SD of 0.046‰ (n=8) for SF 6 zero-enrichment and 0.069‰ (n=8) for overall measurement start from sliver sulfide IAEA-S1. Conclusions: Minimizing the presence of carbon-bearing compounds and avoiding the interfering signals from 36SF 5 + via MAT 253 Ultra high‐resolution isotope-ratio mass spectrometer, we can improve Δ 36S measurement precision by 2 to 5 folds, which helps to open new territories for research using quadruple sulfur isotope composition.

RATIONALE: Urine contains free and conjugated steroids. Total and free steroids were comprehensively quantified; UPLC-MS/MS based on Li adduction allowed for detecting thirteen 3-OH-containing steroids, two of which were detected in human urine for the first time. METHODS: Free urinary steroids were isolated by solid-phase extraction (SPE) with 80% acetonitrile. The total steroids were prepared by enzymatic treatment of urine with a cocktail of sulfatase and glucronidase, protein precipitation, and separation with the above SPE. The free and total steroids were separately analyzed by UPLC-MS/MS with and without introduction of Li + solution. The steroids were quantified by two standard curves created using product ion transitions derived from MH + and [M+Li] +. RESULTS: Two groups of human urine, male and female urine, were analyzed. The absolute amount of each steroid was determined based on creatinine levels. The differences between the male and female groups are clearly attributable to sex steroids. 7-OH P5 and 7-OH DHEA were, for the first time, quantified in the total steroids of female urine, and the latter was identified in both female and male urine. CONCLUSIONS: By combining UPLC-MS/MS based on lithium ion incorporation with conventional UPLC-MS/MS, a total of 29 steroids were identified in human urine containing two newly found steroids.