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 −.

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.

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.

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.

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.

Rationale: Increasing demand for fish and seafood means that traceability of marine products is becoming ever more important for consumers, producers and regulators. Highly complex and globalised supply networks create challenges for verifying the claimed catch region. Atlantic cod is one of the most commercially important species in the northeast Atlantic. Several regional fisheries supply cod into the trade network, of which some are at more risk of overexploitation than others. Tools allowing retrospective testing of spatial origin for traded cod products would significantly assist sustainable harvesting of wild fish, reducing incentives for illegal fishing and fraud. Methods: Here we investigate whether stable isotope ratios of carbon, nitrogen and sulfur in muscle tissue can be used to identify the catch region of Atlantic cod ( Gadus morhua). We measured the isotopic composition of muscle tissue from 377 cod from ten known catch regions across the Northeast Atlantic and Northeast Arctic, and then applied three different assignment methods to classify cod to their region of most likely origin. The assignment method developed was subsequently tested using independent known-origin samples. Results: Individual cod could be traced back to their true origin with an average assignment accuracy of 70-79% and over 90% accuracy for certain regions. Assignment success rates comparable to those using genetic techniques were achieved when the same origin regions were selected. However, assignment accuracy estimated from independent samples averaged c25% overall. Conclusion: Stable isotope techniques can provide effective tools to test for origin in Atlantic cod. However not all catch regions are isotopically distinct. Stable isotopes could be used in conjunction with genetic techniques to result in higher assignment accuracy than could be achieved using either method independently. Assignment potential can be estimated from reference datasets, but estimates of realistic assignment accuracy require independently collected data.

Rationale: Ion chromatography combined with inductively-coupled plasma mass spectrometry is an ideal tool for measuring low concentrations of anionic species such as phosphite; however, the high concentration of chloride and other anions in natural solutions may negatively impact chromatographic separation and data quality. Method: We developed an on-line mechanism of removing chloride from the sample within the ion chromatograph, using an additional valve and a separation column that transfers chloride to waste while phosphite and most other anions are retained. We installed this system in a coupled IC-ICPMS system (ICS6000 and Element 2 in medium resolution mode) and determined linearity and detection limits. In addition, we measured phosphorous species by NMR for comparison as an alternative method for phosphite determination. Results: Chloride was fully removed from the samples while phosphite was retained and could be analysed by IC-ICPMS. Concentrations could be measured down to 0.003 µmol/L and possibly less with good linearity over the explored range (up to 1.615 µmol/L; r 2 = 0.999). In contrast, the detection limit by NMR was 6.46 µmol/L. Conclusions: The on-line removal mechanism works well for simplifying sample matrices. It removes the need for costly pre-analytical sample treatment with OnGuard columns. We confirm that IC-ICPMS is the most powerful technique for quantifying phosphite in natural solutions. The new Cl-removal method may also be applicable to analyses of other anions.

RATIONALE: The thiosuccinimide linker is widely used in the synthesis of bioconjugates. However, it is susceptible to hydrolysis and is transformed into its hydrolyzed and/or the isobaric thiazine forms, the latter of which is a fairly common product in a conjugate that contains a cysteinyl peptide. MALDI-MS and MS/MS are useful for differentiating these isobaric species. METHODS: Four cross-linked peptides with thiosuccinimide linkers were synthesized. Analogs with the linker that were transformed into thiazine and/or the hydrolyzed thiosuccinimide linkers were then generated by incubating the samples at neutral or basic pH. All of the cross-linked peptides were purified by rp-HPLC and differentiated by MALDI-MS, -MS/MS and UVPD. RESULTS: A cysteinyl peptide-containing conjugate, the thiosuccinimide form, was largely transformed into the hydrolyzed or thiazine forms after incubation at neutral or basic pH. MALDI-MS allowed the three forms to be differentiated: the thiosuccinimide and its hydrolysis product gave two constituent peptides after reductive cleavage between the Cys and succinimide moieties; no fragment ions were produced from the thiazine form. In addition, MALDI-MS/MS of the thiosuccinimide form yielded two pairs of complementary fragment ions via 1,4-elimination: Cys-SH and maleimide, and dehydro-alanine and thiosuccinimide, which are different from those produced via reductive cleavage in MALDI-MS. The thiazine form gave fragment ions resulting from the cleavage of the newly formed amide bond in the linker that arose from thiazine formation. CONCLUSIONS: The thiosuccinimide (but not thiazine) form of the cross-linked peptide yielded individual constituent peptides in MALDI-MS; MALDI-MS/MS showing specific 1,4-elimination for the thiosuccinimide form and cleavage at the newly formed peptide bond via transcyclisation for the thiazine form.

RATIONALE: Many chemical processes operate at unsteady state and require a rapid mass analysis of transients with high resolution. An atmospheric pressure interface multi-reflection time-of-flight mass spectrometer (API-MRTOF-MS) has the potential to be a powerful process analytical tool. METHODS: The ion flight path of the API-MRTOF-MS was extended from meters to over one kilometer, and the mass resolution was increased to an ultra-high level. Furthermore, the mass analysis could be done at around ten milliseconds due to the rapidity of TOFMS. The mass analyzer reflects ions via electrostatic mirrors and directs them along a folded flight path, significantly increasing flight distances and theoretically with no upper limit. The powerful API, equipped with two quadrupoles, makes the API-MRTOF-MS suitable for complex mass spectrometry methods with alternative ion selection schemes. RESULTS: A mass resolution of 116,050 for Cs + ions is achieved within a total time-of-flight of only 18 ms. An ion transmission efficiency of over 50% was achieved after 600 cycles. CONCLUSIONS: The performance of the API-MRTOF-MS demonstrates that it is exceedingly suitable for high-resolution process analysis, particularly for transient process analysis, due to its fast analysis speed and high-selectivity.

RATIONALE: SLAP is one of the two calibration materials for the isotopic water scale. By consensus the established δ 18O value is -55.5‰, although there are firm indications that δ 18O SLAP is significantly more negative. The real δ 18O SLAP value as such does not influence the isotopic water scale, however knowledge of the size of isotopic scale contraction in stable isotope measurements is vital for second order isotopes. In this study quantification of δ 18O SLAP with respect to δ 18O VSMOW is described. METHODS: SLAP-like water was quantitatively mixed with highly 18O enriched water to mimic VSMOW. The 18O concentration was determined using an electron ionization quadrupole mass spectrometer. The isotopic composition of the SLAP-like and VSMOW-like waters were measured with an optical spectrometer, alongside real VSMOW and SLAP. RESULTS: This study resulted in a much more depleted δ 18O value for SLAP than expected. The averaged outcome of 7 independent experiments is δ 18O SLAP -56.33 ± 0.03‰. There is a large discrepancy between the actual isotopic measurements of even the most carefully operating groups and the true δ 18O value. CONCLUSIONS: Although this finding as such does not influence the use of the VSMOW-SLAP scale, it raises the intriguing question what we actually measure with our instruments, and why even a fully corrected measurement can be so far off. Our result has consequences for issues like the transfer of δ 18O from and to the VPDB scale, various fractionation factors, and the Δ 17O. The absolute 18O abundance for SLAP was determined at 1.88798 (43) x 10 -3 based on the absolute 18O abundance of VSMOW and the presented δ 18O SLAP in this paper.

The traditional van Krevelen diagram, the nominal oxidation of organic carbon, and several aromaticity indexes generally considered C, H, O, N, P, and S factors, or just C, H, and O. However, these evaluated methods may provide incorrect interpretation for high-resolution mass data of organics containing halogen elements. Therefore, we adapted the van Krevelen diagram and the other indexes with halogen elements and verified with 2235 model organics. The results demonstrated that the modified van Krevelen diagram and the adjusted indexes were more accurate for the analysis of mass data, either in the compound classification or in the evaluation of oxidation state of organic matter.