Quadrupole Time-of-flight Research Articles

Comprehensive Quality Evaluation of Traditional Chinese Medicine Guanxinjing Capsule Based on Fingerprint and Multicomponent Simultaneous Quantitative Method.

A novel dual-wavelength ultrahigh performance liquid chromatography (UHPLC) fingerprint was established, 56 common peaks were confirmed and attributed to the source of the medicinal materials, and 13 chromatographic peaks of them were identified by UHPLC quadrupole time-of-flight (Q-TOF)-MS/MS and UHPLC-UV method. Furthermore, a simple and sensitive HPLC-quadrupole trap (Q-TRAP)-MS/MS was developed for the simultaneous determination of 16 active components with electrospray ionization (ESI) source switching between positive and negative modes in a single run. The above two methods were successfully applied for the quality evaluation of Guanxinjing capsule (GXJC). Finally, statistical analysis including principal component analysis (PCA), hierarchical cluster analysis (HCA), and orthogonal partial least squares discriminate analysis (OPLS-DA) were applied, and 13 variables with great contribution to different groups of samples were screened. This study not only provides a rapid, accurate, and comprehensive qualitative and quantitative method for quality evaluation of GXJC but it also provides a reference workflow for the other traditional Chinese medicines.

Four-Dimensional Lipidomic Analysis Using Comprehensive Online UHPLC × UHPSFC/Tandem Mass Spectrometry.

Multidimensional chromatography offers enhanced chromatographic resolution and peak capacity, which are crucial for analyzing complex samples. This study presents a novel comprehensive online multidimensional chromatography method for the lipidomic analysis of biological samples, combining lipid class and lipid species separation approaches. The method combines optimized reversed-phase ultrahigh-performance liquid chromatography (RP-UHPLC) in the first dimension, utilizing a 150 mm long C18 column, with ultrahigh-performance supercritical fluid chromatography (UHPSFC) in the second dimension, using a 10 mm long silica column, both with sub-2 μm particles. A key advantage of employing UHPSFC in the second dimension is its ability to perform ultrafast analysis using gradient elution with a sampling time of 0.55 min. This approach offers a significant increase in the peak capacity. Compared to our routinely used 1D methods, the peak capacity of the 4D system is 10 times higher than RP-UHPLC and 18 times higher than UHPSFC. The entire chromatographic system is coupled with a high-resolution quadrupole-time-of-flight (QTOF) mass analyzer using electrospray ionization (ESI) in both full-scan and tandem mass spectrometry (MS/MS) and with positive- and negative-ion polarities, enabling the detailed characterization of the lipidome. The confident identification of lipid species is achieved through characteristic ions in both polarity modes, information from MS elevated energy (MSE) and fast data-dependent analysis scans, and mass accuracy below 5 ppm. This analytical method has been used to characterize the lipidomic profile of the total lipid extract from human plasma, which has led to the identification of 298 lipid species from 16 lipid subclasses.

Quantitative Assessment of Core Fucosylation for Congenital Disorders of Glycosylation.

Congenital disorders of glycosylation (CDG) include a group of diseases characterized by defects of N-glycan fucosylation. The analytical molecule of choice for the diagnosis of CDG affecting N-glycosylation is serum transferrin: approximately 10% of the glycans attached to transferrin are fucosylated via an α1,6 linkage at the innermost N-acetylglucosamine residue, termed "core fucosylation." Isoelectric focusing (IEF) of transferrin is often used for diagnosis, but IEF is ineffective in detecting abnormal fucosylation. Here, we present mass spectrometry (MS) methods for detecting fucosylation disorders. First, the level of core fucosylation of the glycan attached to Asn630 of transferrin can be measured by the signal intensity ratio of tryptic peptide ions containing fucosylated and nonfucosylated biantennary oligosaccharides. The core fucosylation level at this glycosylation site in the 0- to 32-year-old group (n = 68) was 7.9 ± 1.7 (%, mean ± SD), and nearly null for SLC35C1-CDG caused by defects in the GDP-fucose transporter. More simply, fucosylation levels can be measured by quadrupole time-of-flight (QTOF) MS of intact transferrin. The fucosylation levels of intact transferrin measured by MS with a Q-mass analyzer, which is currently used as an instrumental standard for newborn screening for inborn errors of metabolism and has a lower resolution than the QTOF analyzer, correlated well with the values obtained by glycopeptide analysis. These methods, namely the analysis of glycopeptides or intact transferrin by Q MS, can also be used on dried blood spots and are expected to help facilitate the diagnosis of CDG affecting N-glycan fucosylation.

A study on the impact of industrial-scale refining on olive oil and olive pomace oil contamination with mineral oils

Mineral oil hydrocarbons (MOH), including saturated (MOSH) and aromatic (MOAH) hydrocarbons, are contaminants of petrogenic origin. On-line high-performance liquid chromatography (HPLC) – gas chromatography (GC) – flame ionization detector (FID) was used for determining MOH in olive oils (OOs) and olive pomace oils (OPOs) at different stages of the refining process and in samples from the Italian market. Deodorization reduced contamination by about 30 %, resulting in a significant reduction of endogenous n-alkanes generally up to n-C31. Comprehensive GC coupled to quadrupole time-of-flight (QTOF) mass spectrometry (MS) allowed investigating the effect of bleaching on a sample of OPO naturally contaminated with alkylated PAHs, demonstrating the removal capacity of this refining step on potentially carcinogenic genotoxic compounds derived from MOH contamination. OOs from the market contained on average 33.1 mg/kg of MOSH n-C10–50 and 3.3 mg/kg of MOAH, while OPOs contained on average 160.7 and 36.1 mg/kg of MOSH and MOAH, respectively.

Probe electrospray ionization coupled to a quadrupole time-Of-flight: A feasibility study for the detection of cocaine and its derivatives in oral fluid

Probe Electrospray Ionization (PESI) is an atmospheric pressure ionization method that can be directly coupled with a mass spectrometer to allow ultrafast analyses without chromatographic separation and with minimal sample preparation. Using the particular case of cocaine and its metabolites in human oral fluid, the main objective of the present study was to test the feasibility of a new hybrid system combining a PESI source and a quadrupole time-of-flight (QTOF). The best results were obtained for a sample preparation with a simple dilution of 100 µL of oral fluids in an ethanol / 10 mM ammonium formate buffer (50/50) and 10 µL deposited on a dedicated sample plate and introduced into the PESI source. For HRMS acquisition, an approach consisting in a full-mass scan (“untargeted approach” from 100 to 500 m/z; MS1) followed by a targeted scheduled MSMS acquisition (precursor ions of the 3 molecules of interest and their 3 internal standards; MS2) gave the best signals. The total time of analysis was 0.45 min and the method was validated according to ISO15189 standard for a 5–100 ng/mL range, including accuracy and precision (inter-day and intra-day precision and bias values were lower than 15 %), matrix effect, carryover and specificity (no interference with a mixture of 119 psychotropic drugs spiked at 1 mg/L). The LLOD values were 1 ng/mL for the 3 cocaine derivatives and 83 Driving Under the Influence of Drug (DUID) cases sent to our Lab for the determination of illicit drugs in oral fluid were analyzed using the PESI-QTOF method and compared to a LC-MS/MS method. A perfect agreement was observed between the 2 methods, whether the cases were positive or negative. Cocaine was detected in 51 out of these 83 real cases (61.6 %). BZE and EME were also simultaneously detected in 50 of them (98.5 %). This feasibility study reports the first analytical method based on a coupling of a PESI source to a QTOF mass spectrometer. Adding the major advantage of high specificity through HRMS is a step forward for PESI technology.

Metabolism of Furanocoumarins by Three Recombinant CYP9A Proteins From the Polyphagous Cotton Bollworm Helicoverpa armigera.

Furanocoumarins are a class of chemical compounds with phototoxic properties. For herbivores, efficient detoxification of such defense compounds is the prerequisite to feed successfully on furanocoumarin-containing plants. The cotton bollworm Helicoverpa armigera is a very important polyphagous pest in agriculture, but how it copes with toxic furanocoumarins in some of its host plants is not well understood. Given that cytochrome P450s are well known for their capacity in xenobiotic metabolism, this study attempted to explore the potential roles of cytochrome P450s in furanocoumarin transformation in this pest. Our data showed that two linear structures (psoralen and xanthotoxin) could be metabolized by three recombinant CYP9A enzymes, but no detectable depletion was observed for the linear one with the 8-dimethylallyloxy substituent on the coumarin moiety (imperatorin) and the angular furanocoumarin (angelicin). Initial epoxidation of the double bond connecting C2' and C3' of the furano ring following by cleavage of the epoxidated furan ring, leading to the formation of more soluble, less reactive and nonphotosensitizing metabolites, was identified as a common mechanism of linear furanocoumarin metabolism using a quadrupole/time-of-flight (Q-TOF) mass spectrometry interfaced with a high performance liquid chromatography (HPLC) system. Our data demonstrated that multiple P450s were involved in the detoxification of linear furanocoumarins in the cotton bollworm. These findings contribute to a better understanding of the biochemical basis of adaptation to plant defense chemicals in this economically important pest.

Investigating the chemical space coverage of multiple chromatographic and ionization methods using non-targeted analysis on surface and drinking water collected using passive sampling

Multiple non-targeted analysis tools were used to look for a broad range of possible chemical contaminants present in surface and drinking water using liquid chromatography separation and high-resolution mass spectrometry detection, including both quadrupole time of flight (Q-ToF) and Orbitrap instruments. Two chromatographic techniques were evaluated on an LC-Q-ToF with electrospray ionization in both positive and negative modes: (1) the traditionally used reverse phase C18 and (2) the hydrophilic interaction liquid chromatography (HILIC) aimed to capture more polar contaminants that may be present in water. Multiple ionization modes were evaluated with an LC-Orbitrap, including electrospray (ESI) and atmospheric pressure chemical ionization (APCI), also in both positive and negative modes. A suspect screening library of over 1300 possible environmental contaminants, including pesticides, pharmaceuticals, personal care products, illicit drugs/drugs of abuse, and various anthropogenic markers was made with experimentally collected data with the LC-Q-ToF with both column types, with 227 chemicals being retained by the HILIC column. The non-targeted methods using multiple chromatographic and ionization modes were applied to environmental water samples collected with polar organic chemical integrative samplers (POCIS), including surface water upstream and downstream from wastewater effluent discharge, and the downstream drinking water intake and treated drinking water for three distinct sampling events. For the LC-Q-ToF, 442 chemical features were detected on the C18 column and 91 with the HILIC column in the POCIS extracts, while 556 features were found on the Orbitrap workflow by ESI and 131 features detected by APCI. Over 100 chemicals were tentatively identified by suspect screening and database searching. The comprehensive and systematic evaluation of these methods serve as a step in characterizing the chemical space covered when utilizing different chromatography and ionization methods, or different instrument workflows on complex environmental mixtures.

Microbiome-derived metabolites in early to mid-pregnancy and risk of gestational diabetes: a metabolome-wide association study

BackgroundPre-diagnostic disturbances in the microbiome-derived metabolome have been associated with an increased risk of diabetes in non-pregnant populations. However, the roles of microbiome-derived metabolites, the end-products of microbial metabolism, in gestational diabetes (GDM) remain understudied. We examined the prospective association of microbiome-derived metabolites in early to mid-pregnancy with GDM risk in a diverse population.MethodsWe conducted a prospective discovery and validation study, including a case–control sample of 91 GDM and 180 non-GDM individuals within the multi-racial/ethnic The Pregnancy Environment and Lifestyle Study (PETALS) as the discovery set, a random sample from the PETALS (42 GDM, 372 non-GDM) as validation set 1, and a case–control sample (35 GDM, 70 non-GDM) from the Gestational Weight Gain and Optimal Wellness randomized controlled trial as validation set 2. We measured untargeted fasting serum metabolomics at gestational weeks (GW) 10–13 and 16–19 by gas chromatography/time-of-flight mass spectrometry (TOF–MS), liquid chromatography (LC)/quadrupole TOF–MS, and hydrophilic interaction LC/quadrupole TOF–MS. GDM was diagnosed using the 3-h, 100-g oral glucose tolerance test according to the Carpenter-Coustan criteria around GW 24–28.ResultsAmong 1362 annotated compounds, we identified 140 of gut microbiome metabolism origin. Multivariate enrichment analysis illustrated that carbocyclic acids and branched-chain amino acid clusters at GW 10–13 and the unsaturated fatty acids cluster at GW 16–19 were positively associated with GDM risk (FDR < 0.05). At GW 10–13, the prediction model that combined conventional risk factors and LASSO-selected microbiome-derived metabolites significantly outperformed the model with only conventional risk factors including fasting glucose (discovery AUC: 0.884 vs. 0.691; validation 1: 0.945 vs. 0.731; validation 2: 0.987 vs. 0.717; all P < 0.01). At GW 16–19, similar results were observed (discovery AUC: 0.802 vs. 0.691, P < 0.01; validation 1: 0.826 vs. 0.780; P = 0.10).ConclusionsDysbiosis in microbiome-derived metabolites is present early in pregnancy among individuals progressing to GDM.

Chemical Profiling, In Silico Pharmacokinetics Analysis and Molecular Docking Study of Phytocompounds of Homeopathy Medicine Echinacea angustifolia Q against Suppurative Bacterial Proteins

Background Computer-aided drug design is the emerging field for identification of drug action on its target organs. The pharmacokinetic study helps find out drug ADMET (absorption, distribution, metabolism, excretion, and toxicity) and drug likeness properties. PyRx software helps with molecular docking of the bioactive compounds on their target organ within a short period of time. In homeopathy, Echinacea angustifolia is one of the most commonly used drugs for microbial infective skin lesions used in internal administration as well as an external application. Objectives This study was aimed at identifying the compounds present in Echinacea angustifolia Q through liquid chromatography mass spectrometry (LC-MS), ADMET, and drug likeness properties, followed by molecular docking by PyRx software to recognize the interaction between drug compounds against 12 target microbial proteins of commonly infective suppurative bacteria. Materials and Methods An analysis of the phytoconstituents of Echinacea angustifolia Q was performed using the Agilent 1290 Infinity LC system coupled to the Agilent 6545 Accurate Mass Quadrupole Time-of-Flight (QTOF) with Agilent Jet Stream Thermal Gradient Technology. In silico ADMET and drug likeness properties were assessed by free online tools, followed by a detailed docking study by PyRx software. The drug compounds with the lower glide docking score are considered to have the best binding affinity. Result The five compounds of Echinacea angustifolia Q satisfy all properties of ADMET and drug likeness. The three compounds of Echinacea angustifolia Q have low glide score of &gt;-7.0 kcal/mol against the three microbial target proteins of Salmonella enterica, Proteus mirabilis, and Staphylococcus aureus. Conclusion Echinacea angustifolia Q has fulfilled the ADMET and drug-likeness properties for internal administration as well as external application for various suppurative bacterial infective disorders, which were confirmed through molecular docking. Therefore, Echinacea angustifolia Q may function as a potential therapeutic agent for the treatment of illnesses associated with antimicrobial resistance.

Sequencing of Phosphorodiamidate Morpholino Oligomers by Hydrophilic Interaction Chromatography Coupled to Tandem Mass Spectrometry.

Sequencing of phosphorodiamidate morpholino oligomers (PMOs) by hydrophilic interaction chromatography (HILIC) coupled to tandem mass spectrometry (MS/MS) is reported. The MS/MS analysis was performed using a quadrupole/time-of-flight (Q-ToF) mass analyzer and collision induced dissociation (CID) in negative ion mode. To improve MS sensitivity in negative ion mode, HILIC conditions, including the separation column, mobile phases, and MS parameters, were optimized. Using the developed HILIC-CID-MS/MS method, 100% sequence coverage was achieved for PMOs ranging from 18-mer to 25-mer. Additionally, the method was successfully applied to identifying positional isomers of n - 1 deletion impurities present in PMO drug substances.

Targeted metabolomics assisted rapid screening and characterization of aristolochic acids and their DNA adducts in aristolochia plants by ultra-high performance liquid chromatography coupled with ion mobility quadrupole time-of-flight mass spectrometry

Aristolochic acids are one of the major compounds in aristolochia plants, which are nephrotoxic and carcinogenic. A method was established for the detection and identification of aristolochic acids and their DNA adducts in four different herbs using ultra-high performance liquid chromatography-ion mobility quadrupole time-of flight mass spectrometry. Solid phase extraction conditions were optimized to improve the sensitivity of the experiment by using 40 mg of C18 as adsorbent and 100 μL ethanol as elution solvent. At a collision energy of 10-40 eV, these compounds and cleavage patterns were precisely identified and analyzed by secondary fragmentation and collision cross section values. The obtained mass spectrometry data were then analyzed by targeted metabolomics, including principal component analysis, partial least squares-discriminant analysis and hierarchical clustering analysis, and importing the samples in the established model, the confidence values can reach 0.61 and 0.76. All in all, this method can provide a useful tool for the detection of aristolochic acids and deoxyribonucleic acid adducts. In conclusion, this method was successfully used for the detection and identification of aristolochic acids and their DNA adducts.

In-depth phytochemical profiling of Roscoea purpurea (Kakoli): Comparative UHPLC-MS/QToF and GC-MS/MS analysis of supercritical CO2 fluid - and conventional solvent - based extractive processes

The remarkable biodiversity of medicinal plants worldwide highlights their significance in traditional and alternative medicine. Astavarga, a group of eight medicinal herbs from the Himalayan region of India, including Roscoea purpurea (commonly known as Kakoli), is esteemed in Ayurveda for its health-promoting and rejuvenating properties. In this comprehensive study, we aimed to develop and optimise robust UHPLC-MS/QToF (Ultra-high-performance liquid chromatography-mass spectrometry coupled with quadrupole time of flight) and GC-MS/MS (Gas chromatography-tandem mass spectrometry) methods to identify the phytochemicals in R. purpurea root hydromethanolic extract and essential oil. We also conducted a comparative assessment of supercritical fluid extraction and conventional solvent extraction methods for the first time in R. purpurea root, highlighting their relevance to the medicinal field. Using the UHPLC/MS-QToF method, we identified a total of fifty-six phytometabolites, while sixteen volatile constituents were discerned within the essential oil of R. purpurea by GC-MS/MS method. Among the volatile constituents, β-eudesmol (40.84 %), guaiac acetate (10.55 %), and γ-eudesmol (10.31 %) were emerged as the principal components. Our findings were further compared with the volatile constituents extracted via supercritical fluid extraction and conventional solvent extraction methods. Notably, our research unveiled the presence of a carotenoid metabolite, 15-methyl retinol, for the first time. Furthermore, our fatty acid analysis of the supercritical fluid extract revealed elevated levels of unsaturated fatty acids, particularly oleic and linoleic acids. The methods were validated in terms of system specificity also. The discovery of these well-recognised therapeutically active components in R. purpurea significantly enhances its potential, highlighting its unique profile among medicinal plants in the Himalayan region and its suitability for traditional Ayurveda.

Direct Three-Dimensional Mass Spectrometry Imaging with Laser Ablation Remote Atmospheric Pressure Photoionization/Chemical Ionization.

The laser ablation remote atmospheric pressure photoionization/chemical ionization (LARAPPI/CI) platform coupled to an ultrahigh resolution quadrupole-time-of-flight (QToF) mass spectrometer was developed and employed for the first direct three-dimensional (3D) mass spectrometry imaging (MSI) of metabolites in human and plant tissues. Our solution for 3D MSI does not require sample modification or cutting into thin slices. Ablation characteristics of an optical system based on a diffraction optical element are studied and used for voxel stacking to directly remove layers of tissues. Agar gel, red radish, kiwi, human kidney cancer, and normal tissue samples were used for the tests of this new system. The 2D and 3D ion images vividly illustrate differences in the abundances of selected metabolites between cancerous and noncancerous regions of the kidney tissue and also between different parts of plant tissues. The LARAPPI/CI MSI setup is also the first example of the successful use of combined dopant-assisted atmospheric pressure photoionization (DA-APPI) and atmospheric pressure chemical ionization (APCI) ion source for mass spectrometry imaging.

Leveraging High-Resolution Ion Mobility-Mass Spectrometry for Cyclic Peptide Soft Spot Identification.

Cyclic peptides are an important class of molecules that gained significant attention in the field of drug discovery due to their unique pharmacological characteristics and enhanced proteolytic stability. Yet, gastrointestinal degradation remains a major hurdle in the discovery of orally bioavailable cyclic peptides. Soft spot identification (SSID) of the regions in the cyclic peptide sequence susceptible to amide hydrolysis by proteases is used in the discovery stage to guide medicinal chemistry design. SSID can be an arduous task, traditionally performed using liquid chromatography-tandem mass spectrometry (LC-MS/MS), often resulting in complex and time-consuming manual analysis, particularly when isomeric linear peptide metabolites chromatographically coelute. Here, we present an alternative orthogonal approach that entails a high-resolution ion mobility (HRIM) system based on Structures for Lossless Ion Manipulation (SLIM) technology interfaced with quadrupole time-of-flight (QTOF) mass spectrometry to address some of the challenges associated with SSID. Two strategies were used to resolve linear isomeric peptide metabolites: labeled and label-free, both utilizing the HRIM platform. The label-free strategy leverages negative polarity to ionize the isomers which achieves better separation of the gas phase ions in the ion mobility (IM) dimension as compared to positive polarity, which is a more conventional approach when studying proteins and peptides. The second approach uses an isotope-labeled dimethyl tag on the terminal amine group, acting as a "shift reagent" to influence the mobility of isomers in the positive mode. This method resulted in baseline separation for the isomers of interest and produced unique product ions in the fragmentation spectra for unambiguous soft spot identification. Both label-free and labeled strategies demonstrated the ability to solve the challenges associated with SSID for cyclic peptides.

An exploratory study on lipidomic profiles in a cohort of individuals with posttraumatic stress disorder

Posttraumatic stress disorder (PTSD) can develop after trauma exposure. Some studies report that women develop PTSD at twice the rate of men, despite greater trauma exposure in men. Lipids and their metabolites (lipidome) regulate a myriad of key biological processes and pathways such as membrane integrity, oxidative stress, and neuroinflammation in the brain by maintaining neuronal connectivity and homeostasis. In this study, we analyzed the lipidome of 40 adults with PTSD and 40 trauma-exposed non-PTSD individuals (n = 20/sex/condition; 19–39 years old). Plasma samples were analyzed for lipidomics using Quadrupole Time-of-Flight (QToF) mass spectrometry. Additionally, ~ 90 measures were collected, on sleep, and mental and physical health indices. Poorer sleep quality was associated with greater PTSD severity in both sexes. The lipidomics analysis identified a total of 348 quantifiable known lipid metabolites and 1951 lipid metabolites that are yet unknown; known metabolites were part of 13 lipid subclasses. After adjusting for BMI and sleep quality, in women with PTSD, only one lipid subclass, phosphatidylethanolamine (PE) was altered, whereas, in men with PTSD, 9 out of 13 subclasses were altered compared to non-PTSD women and men, respectively. Severe PTSD was associated with 22% and 5% of altered lipid metabolites in men and women, respectively. Of the changed metabolites, only 0.5% measures (2 PEs and cholesterol) were common between women and men with PTSD. Several sphingomyelins, PEs, ceramides, and triglycerides were increased in men with severe PTSD. The correlations between triglycerides and ceramide metabolites with cholesterol metabolites and systolic blood pressure were dependent upon sex and PTSD status. Alterations in triglycerides and ceramides are linked with cardiac health and metabolic function in humans. Thus, disturbed sleep and higher body mass may have contributed to changes in the lipidome found in PTSD.

High-performance supercritical fluid chromatography hyphenated to high-resolution quadrupole-time of flight hybrid mass spectrometry (SFC-HR-QTOF-MS/MS) for the determination of cannabinoids in edible products

A growing number of papers suggest the positive action of cannabinoids in the treatment of several diseases, which is ascribed to the ability of phytocannabinoids to affect the human endocannabinoid system. In particular, this activity is characteristic of CBD, a non-psychoactive variation of 9-THC. It initiated a trend in the manufacturing of edible and cosmetic products containing CBD that can be easily acquired in drugstores. However, the composition of such products has rarely been tested. Hence, there is a need for data regarding their safety. Considering the possibility of cannabinoid interconversions as well as the complexity and diversity of edible products’ matrix, their analysis requires a suitable preparation and cleanup procedure. In this paper, the perspective of the application of Supercritical Fluid Chromatography (SFC) coupled to High-Resolution (HR) Quadrupole-Time of Flight (Q-TOF) tandem mass spectrometry (MS/MS) with electrospray ionization (ESI) in quality control of cannabis-containing food products was examined. The focus is on six neutral (CBD, 9-THC, CBC, CBG, CBN, and THCV) and three acidic (CBDA, THCA, and CBGA) cannabinoids. The study covers the thorough optimization of conditions for chromatographic separation with the use of the supercritical CO2 (scCO2)-based mobile phase and the working parameters of MS/MS detection with the elucidation of fragmentation patterns. Thanks to the utilization of scCO2, a short analysis time of 17 min., high intensity and small width of peaks, as well as low consumption of toxic organic solvent have been achieved at the 2-EP column with a 5 μm grain size. To reach such performance in LC, the utilization of more expensive columns packed with sub-2 μm particles is needed. In the case of the solvent matrix, the LOD was equal to 8 ng mL−1 for CBDA, THCA, and CBGA, 15 ng mL−1 for CBG and THCV, and 21 ng mL−1 for THC, CBD, CBC, and CBN. In the case of tea, an LOD of 25 ng mL−1 for acidic and 75 ng mL−1 for neutral cannabinoids has been obtained. The accuracy and precision were within the ± 15 % tolerance limit. Finally, the devised protocol has been applied for cannabinoid determination in hemp tea infusions.

Electrospray ionization tandem mass spectrometry of 4-aryl-3,4-dihydrocoumarins.

We have investigated the gas-phase fragmentation reactions of 11 synthetic 4-aryl-3,4-dihydrocoumarins by electrospray ionization tandem mass spectrometry (ESI-MS/MS) on a quadrupole-time-of flight (Q-TOF) hybrid mass spectrometer. We have also estimated thermochemical data for the protonated coumarins (precursor ion A) and product ion structures by computational chemistry at a B3LYP level of theory to establish the ion structures and to rationalize the fragmentation pathways. The most abundant ions in the product ion spectra of coumarins 1-11 resulted from C8H8O2, CO2, C4H4O3, C8H10O3, C8H8O2, and CH3OH eliminations through retro-Diels-Alder (RDA) reactions, remote hydrogen rearrangements (β-eliminations), and β-lactone ring contraction. Although the investigated coumarins shared most of the fragmentation pathways, formation of a benzylic product ion and its corresponding tropylium ion was diagnostic of the substituents at ring C. The thermochemical data revealed that the nature and position of the substituents at ring C played a key role in the formation of this product ion and determined its relative intensity in the product ion spectrum. The results of this study contribute to knowledge of the gas-phase ion chemistry of this important class of organic compounds.

Photodecomposition of antibiotics and their transformation products in wastewaters using ZnO and TiO2 with LED lamps

This work presents a study of the behavior of three antibiotics (erythromycin (ERY), clarithromycin (CLR) and sulfadiazine (SFZ)) and their transformation products (TPs), generated after photolytic and photocatalytic (TiO2 and ZnO) treatments, in wastewater irradiated with ultraviolet (UV) light emitting diode (LED) lamps as light source. For this, an analytical methodology for the antibiotics and their TPs was developed. Thus, samples were treated by salting-out assisted liquid–liquid extraction (SALLE) and identification and quantification was carried out by liquid chromatography with mass spectrometry (LC-MS) using quadrupole time-of-flight (QTOF) and triple quadrupole (QqQ) analyzers, respectively. The results revealed the presence of 14, 13 and 5 TPs of ERY, CLR and SFZ, respectively, being found in wastewaters spiked with the antibiotics during photo-oxidation treatment. Subsequently, the established analytical method was also applied, in a real case, to study of behavior of these pharmaceuticals (0.2 mg L-1) and their TPs generated in wastewater during a photocatalytic treatment. In this case, 13, 11 and 2 TPs were tentatively identified ERY, CLR and SFZ, respectively. In addition, the photocatalytic treatment using TiO2 exhibited higher degradation rate than photocatalytic treatment using ZnO. The ECOSAR programme was used to estimate the potential ecotoxicity of the identified TPs. The results showed a potential hazard of SFZ, CLR, ERY and some of their TPs to aquatic organisms. Furthermore, some of the identified TPs were found to be more toxic than their parent compounds.

Quality control in SARS-CoV-2 RBD-Fc vaccine production using LC–MS to confirm strain selection and detect contaminations from other strains

Coronavirus disease of 2019 (COVID-19), caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), is an ongoing outbreak, disrupting human life worldwide. Vaccine development was prioritized to obtain a biological substance for combating the viral pathogen and lessening disease severity. In vaccine production, biological origin and relevant materials must be carefully examined for potential contaminants in conformity with good manufacturing practice. Due to fast mutation, several SARS-CoV-2 variants and sublineages have been identified. Currently, most of COVID-19 vaccines are developed based on the protein sequence of the Wuhan wild type strain. New vaccines specific for emerging SARS-CoV-2 strains are continuously needed to tackle the incessant evolution of the virus. Therefore, in vaccine development and production, a reliable method to identify the nature of subunit vaccines is required to avoid cross-contamination. In this study, liquid chromatography-mass spectrometry using quadrupole-time of flight along with tryptic digestion was developed for distinguishing protein materials derived from different SARS-CoV-2 strains. After analyzing the recombinantly produced receptor-binding domain (RBD) of the SARS-CoV-2 spike protein, nine characteristic peptides were identified with acceptable limits of detection. They can be used together to distinguish 14 SARS-CoV-2 strains, except Kappa and Epsilon. Plant-produced RBD-Fc protein derived from Omicron strains can be easily distinguished from the others with 4–5 unique peptides. Eventually, a peptide key was developed based on the nine peptides, offering a prompt and precise flowchart to facilitate SARS-CoV-2 strain identification in COVID-19 vaccine manufacturing.

Insight into the generation of toxic by-products during UV/H2O2 degradation of carbamazepine: Mechanisms, N-transformation and toxicity

Carbamazepine (CBZ) is a widely used anticonvulsant drug that has been detected in aquatic environments. This study investigated the toxicity of its by-products (CBZ-BPs), which may surpass CBZ. Unlike the previous studies, this study offered a more systematic approach to identifying toxic BPs and inferring degradation pathways. Furthermore, quadrupole time-of-flight (QTOF) and density functional theory (DFT) calculations were employed to analyze CBZ-BP structures and degradation pathways. Evaluation of total organic carbon (TOC) and total nitrogen (TN) mineralization rates, revealed carbon (C) greater susceptibility to mineralization compared with nitrogen (N). Furthermore, three rules were established for CBZ decarbonization and N removal during degradation, observing the transformation of aromatic compounds into aliphatic hydrocarbons and stable N-containing organic matter over time. Five potentially highly toxic BPs were screened from 14 identified BPs, with toxicity predictions guiding the selection of commercial standards for quantification and true toxicity testing. Additionally, BP207 emerged as the most toxic, supported by the predictive toxicity accumulation model (PTAM). Notably, highly toxic BPs feature an acridine structure, indicating its significant contribution to toxicity. These findings offered valuable insights into the degradation mechanisms of emerging contaminants and the biosafety of aquatic environments during deep oxidation.