Chromatography-tandem Quadrupole Mass Spectrometry Research Articles

UHPLC-MS/MS analysis of the influence of paclobutrazol application on Ophiopogon japonicus

The pharmacological effects of Ophiopogon japonicus are influenced by its active substances like saponins and flavonoids, which are crucial for assessing its quality. An ultra-high performance liquid chromatography tandem triple quadrupole mass spectrometry (UHPLC-MS/MS) method was developed for the qualitative and quantitative assessment of 20 saponins and flavonoids in O. japonicus. The average recovery of these compounds ranged from 70% to 130%, with relative standard deviations (RSD) between 0.11% and 16.46%. Planting O. japonicus in Santai County (Sichuan, China) and investigated the impact of 0.6, 1.3, 2.8, 5.6, and 11.3g/L concentrations of paclobutrazol on both root yield and the levels of saponins and flavonoids in O. japonicus. Lower paclobutrazol concentrations (1.3g/L) led to increased levels of saponins and flavonoids in O. japonicus such as ophiopogonin D′, ruscogenin and ophiopogonanone F, with paclobutrazol residues measuring 77.17μg/kg DW. This preliminary insight into the influence of paclobutrazol and production of saponin flavonoids in O. japonicus bears significance for its larger industrial production.

Mediating effect of oxidative stress on blood pressure elevation in workers exposed to low concentrations of benzene, toluene, and xylene (BTX).

To investigate the mediating effect of oxidative stress on the relationships between low-concentration benzene, toluene, and xylene (BTX) exposure and blood pressure in workers. A cross-sectional study involving 841 workers from a petroleum refining enterprise in Hainan, China, was conducted. Among the workers, 615 workers were exposed to low-concentration BTX, and 216 workers were in the control group. S-phenylmercapturic acid (S-PMA), hippuric acid (HA), and methyl hippuric acid (MHA, including the three isomers 2-MHA, 3-MHA, and 4-MHA) were measured in the urine of workers via high-performance liquid chromatography‒tandem triple quadrupole mass spectrometry to assess the internal BTX burden. Oxidative stress markers, blood pressure, and their correlations were analysed in both the exposed and control groups of workers. Mediation analysis was used to investigate the potential role of oxidative stress in the relationship between BTX exposure and blood pressure. The concentrations of BTX at the sampling points in the enterprise were all below the limits stipulated in China's national occupational health criteria: occupational exposure limits for hazardous agents. With respect to the internal burden of BTX, the concentrations of the benzene metabolite S-PMA, the toluene metabolite HA, and the xylene metabolites 3-MHA and 4-MHA in the urine samples in the exposure group were greater than those in the control group (P < 0.05). The correlation analysis results revealed that the concentration of the benzene metabolite S-PMA in workers' urine was positively correlated with diastolic blood pressure (DBP) (r = 0.265, P < 0.05). Compared with those in the control group, DBP was greater (β = 1.363, 95% CI 0.088 -2.639), serum superoxide dismutase (SOD) activity was lower (β = - 0.037, 95% CI - 0.060 to - 0.013), and the serum malondialdehyde (MDA) concentration was greater (β = 0.066, 95% CI 0.022-0.110) in the exposure group. Partial correlation analysis revealed a positive correlation between DBP and MDA (rs = 0.115, P < 0.01). The results of the mediation analysis indicated that MDA was a complete mediator between low BTX exposure and DBP (P < 0.05). Occupational exposure to low concentrations of BTX elevates blood pressure and oxidative stress among workers. A positive correlation between DBP and MDA was observed, with MDA acting as a complete mediator between low-concentration BTX exposure and DBP elevation.

Magnetic surface-imprinted polymer microspheres coupled with HPLC-MS/MS for sensitive detection of amphetamine-type drugs in water

Magnetic surface imprinted polymer microspheres (Fe3O4@MIPs) were successfully synthesized via Pickering emulsion polymerization, utilizing N-Methylphenethylamine as a surrogate template for amphetamine-type drugs. Fe3O4@MIPs not only possessed excellent dispersibility and enough magnetic properties in aqueous solutions, but also displayed good selectivity towards six amphetamines, with an imprinting factor ranging from 1.8 to 2.6. The adsorption kinetics closely aligned with the pseudo-second-order model, and the adsorption efficiency exceeds 80 % for each amphetamine at equilibrium. Fe3O4@MIPs were then employed as the efficient adsorbents for the extraction of amphetamine drugs. Extraction parameters, including sample pH, the mass of adsorbent, and the type and volume of eluting solvent, were carefully optimized. In combination with the high performance liquid chromatography tandem triple quadrupole mass spectrometry (HPLC-MS/MS), a selective magnetic solid-phase extraction (MISPE) method utilizing Fe3O4@MIPs was developed for the detection of six amphetamines in water samples. The limits of detection and limits of quantitation were determined to be 5.2∼23 ng L−1 and 17∼77 ng L−1, respectively. Recoveries for the six target drugs from lake water and sewage samples fell within the range of 87.2∼110 %. Additionally, the MISPE-HPLC-MS/MS method exhibited excellent repeatability, with a precision below 8.5 % at two spiking levels. The prepared Fe3O4@MIPs possessed the advantages of high selectivity, straightforward preparation, facile separation and good reusability, and was highly suitable for the efficient extraction of amphetamine-type substances in complex environmental water.

A multi-technique based analytical platform for characterization and identification of a newly emerged steroid 6β-chlorotestosterone and its in-vivo epimeric metabolites

Doping athletes tend to use new and non-approved drugs in an attempt to circumvent the dope test. Recently, a package of unknown drug was obtained from black market claiming to contain steroid-like compound, which could not be readily identified due to the lack of commercially available reference standards. In order to characterize and identify the chemical structure of the unknown compound, ultra performance liquid chromatography high resolution mass spectrometry (UPLC-HRMS), high performance liquid chromatography tandem quadrupole mass spectrometry (HPLC-MS/MS), gas chromatography tandem quadrupole mass spectrometry (GC–MS/MS) and nuclear magnetic resonance (NMR) instruments were applied in this work. Based on the combined data, the unknown compound was identified as 6β-chlorotestosterone. The aim of this study was to find urinary metabolic biomarkers of 6β-chlorotestosterone for clinical research and doping control analysis. Ten in-vivo metabolites including four phase I metabolites and six phase II metabolites were characterized and potentially identified. The detailed structure of the phase I metabolite was successfully obtained by GC–MS/MS analysis of trimethylsilylation (TMS) released upon dissolution, overcoming the absence of useful fragment ions to demonstrate the structure of sulfate metabolites. Two strategies including metabolic mechanisms and retention time variation of steroids were introduced to determine and distinguish 3α/β- and 5α/β- epimeric metabolites. A comprehensive evaluation was conducted on time of appearance and detection of each metabolite. The sulfate metabolite 6β-chloro-5β-androstan-17-one-3β-O-sulfate (S1) could be detected up to 12 days after oral administration, which was considered to be the long term biomarker for 6β-chlorotestosterone abuse in clinical research and doping control analysis.

A randomized control trial to test the effect of pegbovigrastim treatment at dry-off on plasma and milk oxylipid profiles during early mammary gland involution and the postparturient period

The early period of mammary gland involution is a critical juncture in the lactation cycle that can have significant effects on milk production and mammary gland health. Pegbovigrastim (PEG) administered 1 wk prior and on the day of parturition can enhance immune function and reduce the incidence of mastitis in the early postpartum period. Oxylipids are potent metabolites of polyunsaturated fatty acids (PUFA) and are important mediators of inflammation. The objective of this study was to evaluate effects of PEG given 1 wk before and at the day of dry-off (D0) on concentrations of oxylipids in plasma and milk from 7 d before D0 to 14 d after, as well as the effects during the first 14 d of the subsequent lactation. We hypothesized that both pro- and anti-inflammatory oxylipids would vary based on initiation of mammary gland involution and that pegbovigrastim would affect oxylipid concentrations, particularly those related to leukocytes. A complete randomized blocked design was used to enroll cows into either a PEG treatment group (n = 10) or control group (n = 10; CON). Blood samples were collected -7, -2, -1, 0, 1, 2, 4, 7, and 14 d relative to dry-off and 5, 10, and 14 d postcalving. Samples were analyzed for PUFA and oxylipids in milk and plasma by ultra-performance mass spectrometry and liquid chromatography tandem quadrupole mass spectrometry, respectively. Overall, 30 lipid mediators were measured in both milk and plasma. Repeated measures analyses revealed a significant interaction of treatment by time for milk 8-iso-keto-15-prostaglandin E2, prostaglandin F2α, plasma 8,12-iso-prostaglandin Fα-VI, 11-hydroxyeicosatetraenoic acid, and 12-hydroxyheptadecatienoic acid. The majority of milk PUFA and oxylipids differed significantly during early mammary gland involution and into the early postpartum period. This study demonstrated changes in oxylipids in milk secretions and plasma during early involution, and further investigation may illuminate multiple complex processes and reveal targets for optimization of mammary gland involution.

A Negative Association between Plasma Phylloquinone and All-Cause Mortality in Chinese Adults with Hypertension: A Nested Case-Control Study

BackgroundPrevious studies have revealed that vitamin K is essential for preventing various chronic diseases. Phylloquinone is the primary dietary and circulating form of vitamin K. However, data concerning the association between plasma phylloquinone and all-cause mortality are limited. ObjectivesThis study aimed to evaluate the association between plasma phylloquinone and risk of all-cause mortality and examine some potential confounders. MethodsThis study is a post hoc analysis of the RCT and a nested, case-control design was used. Enrolled participants had to have hypertension at baseline. Study initiation was 19 May, 2008, and the median follow-up was 4.5 y. A total of 604 mortality cases and 604 controls matched for age, sex, treatment group, and study site were included in this study. Odds ratios (OR) and 95% confidence intervals (CIs) of all-cause mortality were calculated using conditional or unconditional logistic regression, without or with adjusting for pertinent covariates, respectively. The concentration of phylloquinone was measured by liquid chromatography–tandem quadrupole mass spectrometry (LC-MS/MS). ResultsThe mean and median phylloquinone levels were 1.62 nmol/L and 0.89 nmol/L, respectively. There was a significant negative association between log-transformed plasma phylloquinone and all-cause mortality after controlling for potential confounders (per 1 unit increase-OR: 0.79; 95% CI: 0.66, 0.95). Furthermore, the association of plasma phylloquinone with risk of all-cause mortality differed by body mass index (BMI) (<25 kg/m2 compared with ≥25 kg/m2, P-interaction = 0.004). A significant trend of decreasing risk with increasing concentration of phylloquinone was observed in participants with higher BMI (per 1 unit increase-OR: 0.71; 95% CI: 0.56, 0.90; P = 0.004). No significant correlation was found between phylloquinone and risk of all-cause mortality in those with BMI <25 kg/m2. ConclusionsIn Chinese patients with hypertension, there was a significant negative association between baseline plasma phylloquinone and all-cause mortality, especially among those with higher BMI.

Boron quantification using ion chromatography tandem triple quadrupole mass spectrometry. Application to retention analysis in boron-treated wood

Boron compounds play a crucial role in various industries, and accurate quantification of boron is essential for quality control and environmental monitoring. This study presents a simple, rapid, and reliable method for determining boron in aqueous solutions using suppressed ion chromatography coupled to electrospray ionisation-triple quadrupole mass spectrometry (IC-ESI-QqQ-MS). Boric acid (B(OH)3) was retained as the tetrahydroxyborate ion (B(OH)4−) on a CarboPac PA300-4 μm anion-exchange column using isocratic elution with 40 mM KOH. During the neutralization process at the suppressor, B(OH)4− was converted to B(OH)3, which subsequently generated the metaborate ion [BO2]− (m/z 43) within the electrospray ionisation source. By employing a pseudo-selected reaction monitoring (SRM) transition from m/z 43 to m/z 43, the method achieved a limit of detection (LOD) of 2.45 μg/L of boron, the lowest reported in the literature to-date for an IC-based method. The analytical performance of the method demonstrated no carry-over issues, no matrix interferences, and excellent intra- and inter-run repeatability of 2.03% and 3.41%, respectively. The method was applied to the evaluation of boron uptake and retention by Tasmanian Oak timber blocks, treated by dip-diffusion in a boric acid solution of 2.5% Boric Acid Equivalent (BAE, m/m) under controlled laboratory conditions. Quantitative determination of the retained and unretained boron allowed a mass balance evaluation and confirmed the accuracy and reliability of the method, with recoveries ranging from 99.3% to 100.2%.

Simultaneous determination of three strong polarity herbicides in tea by ion chromatography-triple quadrupole mass spectrometry

Due to lack of chromogenic groups and fluorescence groups, high boiling point, high polarity, low volatility, and small molecular weight of glyphosate, glufosinate and bentazone, the detection of three analyses were limited in all kinds of food. Herein, a method for the simultaneous determination of glyphosate, glufosinate and bentazone in tea by ion chromatography tandem triple quadrupole mass spectrometry (IC-MS) was developed, which is without organic solvent and complex derivatization. The recoveries of three compounds in different teas (black tea, green tea, white tea) ranged from 80.40 % to 107.00 %, and the intraday precision (n = 6) ranged from 0.57 % to 9.90 %, the daytime precision ranged from 1.00 % to 5.30 %, the quantitative limit (LOQ) ranged from 0.36 to 1.30 µg/L, and the detection limit (LOD) ranged from 0.11 to 0.39 µg/L. Furthermore, the detection limit and quantitative limit of glyphosate, glufosinate and bentazone by this method are lower than other methods in real samples. Meanwhile, the established method was successfully applied to determine the terminal residues of the three analytes in twelve tea samples from commercial market. Therefore, this method can provide reliable technical support for the study of residue status in vegetables and fruits.

Analytical Techniques in Exploring the Persistent Global PFAS Problem

Per- and polyfluoroalkyl substances (PFAS) are synthetic chemicals with unique properties. They are used in a wide range of different industries because they repel water and oil, and they are heat-resistant. However, PFAS contamination has become a widespread global concern because of their ubiquitous occurrence, persistence in the environment and living organisms, and potential health risks. Governments around the world are continuously introducing and updating regulatory limits for PFAS in drinking water, other types of water, biota, and, most recently, food. Analyzing such a wide range of sample types for PFAS requires high sensitivity and selectivity, typically provided by methods based on advanced liquid chromatography–tandem quadrupole mass spectrometry (LC–MS/MS) instrumentation. However, one critical aspect to sampling and analyzing PFAS accurately is to avoid PFAS contamination during these processes. This paper emphasizes the significance of robust and reliable PFAS analysis to support efforts to mitigate the global PFAS crisis. Collaboration, research, and advanced analytical solutions are essential to safeguard food, water, and the environment, thusly reducing the impact of PFAS on public health and the environment.

Identification of a Bacillus thuringiensis Q1 compound with algicidal activity

Bacillus thuringiensis Q1, isolated from the eutrophic waters of the Haihe River in Tianjin, possesses remarkable algae dissolving character. We determined the lytic effect of B. thuringiensis Q1 fermentation broth, and it proved to be pH- and temperature-stable. Then, we investigated the structure of the algicidal compound by high performance liquid chromatography, gas chromatography tandem quadrupole mass spectrometry and fourier transform infrared spectroscopy, and identified as purine-derived C12H15O5N5. To further understand B. thuringiensis Q1, we performed genome sequencing and analysis. The genome was 5341610 bp, with 35.31% GC content. Some elements involved in algicidal activity, such as quorum sensing pathway and ABC transporter were predicted. Our results reveal that B. thuringiensis Q1 can be used for biological control of harmful algal blooms.

A comprehensive analytical strategy based on characteristic fragments to detect synthetic cannabinoid analogs in seized products and hair samples

Synthetic cannabinoids, one of the most widely abused new psychoactive substances (NPS), are now placed under national control generally in China. Due to continuous modification of synthetic cannabinoid structure, an ongoing dilemma in the forensic laboratory is that newly emerging substances cannot be detected by established methods. Thus, the screening methods for simultaneous detection of known or unknown substances have become research hotspots. In this study, the ultra high performance liquid chromatography tandem triple quadrupole mass spectrometry (UPLC-QqQ-MS) with precursor ion scan (PIS) as acquisition mode was used for prescreening purposes of all possible synthetic cannabinoids-related substances. In detail, four common characteristic fragments, m/z of 144.0, 145.0, 135.1, and 109.0 corresponding to acylium-indole, acylium-indazole, adamantyl, and fluorobenzyl cation respectively, were selected for PIS mode, and their collision energies were optimized by 97 available synthetic cannabinoids standards with relevant structures. Those suspicious signals observed in the screening experiment were confirmed by ultra high performance liquid chromatography tandem quadrupole time-of-flight mass spectrometry (UPLC-QTOF-MS) via high-resolution MS and MS2 data obtained by full scan (TOF MS) and product ion scan mode. After methodological validation, the integrated strategy established above was applied to the screening and identification of the seized e-liquids, herbal blends and hair samples, confirming the presence of multiple synthetic cannabinoids in these samples. In particular, a novel synthetic cannabinoid was identified as 4 F-ABUTINACA, for which no relevant high-resolution mass spectrometry (HRMS) data has been retrieved until now, making this study the first to report the cleavage pattern of this compound in electrospray ionization (ESI) mass spectrometry. In addition, four other suspected by-products of the synthetic cannabinoids were found in the herbal blends and e-liquids, and their possible structures were also deduced via the information from high-resolution mass spectra.

Trace Elements and Persistent Organic Pollutants in Unhatched Loggerhead Turtle Eggs from an Emerging Nesting Site along the Southwestern Coasts of Italy, Western Mediterranean Sea

Marine pollution is one of the major threats affecting loggerhead turtles, which due to their long life span, highly migratory behavior, and carnivorous diet, may be exposed to elevated levels of toxic elements throughout their life. The transfer of chemicals from mothers to their offspring is of particular conservation concern because it may affect embryonic development and hatching success. In this study, the concentrations of 16 toxic and potentially toxic trace elements, 6 indicator polychlorinated biphenyls (PCBs), and organochlorine pesticide residues (OCPs) were determined in 138 eggs from 46 loggerhead turtle nests laid during the 2021 nesting season in Campania, Italy, western Mediterranean Sea. The possible impact of pollutant levels on hatching success and early embryonic death was also investigated. Trace element analysis was performed using an ICP-MS, except for mercury, which was determined using a Direct Mercury Analyzer® (DMA). PCBs and OCPs were analyzed with high-resolution gas chromatography coupled with high-resolution mass spectrometry (HRGC-HRMS) and gas chromatography tandem quadrupole mass spectrometry GC-MS /MS, respectively. The concentrations of essential elements in the eggs were higher than those of non-essential elements. In addition, the highly chlorinated PCBs (153, 138, and 180) contributed the most to the total PCBs, while OCPs were not detected. No correlations were found between contaminant concentrations and reproductive parameters (hatching success and no obvious embryos). The results obtained suggest that the levels of contaminants found in the eggs do not affect the reproductive success of the species in the study area.

Polygoni Multiflori Radix interferes with bile acid metabolism homeostasis by inhibiting Fxr transcription, leading to cholestasis.

Objective: To explore the possible mechanisms of cholestasis induced by Polygoni Multiflori Radix (PM). Methods: Low and high doses of water extract of PM were given to mice by gavage for 8weeks. The serum biochemical indexes of aspartate aminotransferase (AST), alanine aminotransferase (ALT), glutamyltransferase (GGT) alkaline phosphatase (ALP) and so on were detected in the second, fourth, sixth, and eighth weeks after administration. At the end of the eighth week of administration, the bile acid metabolic profiles of liver and bile were screened by high-performance liquid chromatography tandem triple quadrupole mass spectrometry (HPLC-QQQ-MS/MS). Liver pathological changes were observed by hematoxylin and eosin staining. Real-time quantitative polymerase chain reaction (RT-qPCR) was used to detect the mRNA transcription of the target genes and Western blotting (WB) was used to the detect target protein expression. Results: Biochemical tests results showed the values of ALP and GGT were two and three times greater than the normal values respectively, and the value of R was less than 2. Histopathology also showed that PM caused lymphocyte infiltration, a small amount of hepatocyte necrosis and nuclear fragmentation in mouse liver. The proliferation of bile duct epithelial cells was observed in the high group. These results indicated that PM may lead to cholestatic liver injury. HPLC-QQQ-MS/MS analysis with the multivariate statistical analysis revealed significant alterations of individual bile acids in liver and gallbladder as compared to those of the control group. RT-qPCR showed that the transcription of Fxr, Shp, Bsep, Bacs, Mdr2, and Ugt1a1 were downregulated and that of Cyp7a1, Mrp3, and Cyp3a11 was significantly upregulated in the treatment group. WB demonstrated that PM also markedly downregulated the protein expression of FXR, BSEP, and MDR2, and upregulated CYP7A1. Conclusion: PM inhibited the expression of FXR, which reduced the expression of MDR2 and BSEP, leading to the obstruction of bile acids outflow, and increased the expression of CYP7A1, resulting in an increase of intrahepatic bile acid synthesis, which can lead to cholestasis.

A sensitive LC-MS/MS method-based pharmacokinetic study of fifteen active ingredients of Yindan Xinnaotong soft capsule in rats and its potential mechanism in the treatment of cardiovascular diseases

Yindan Xinnaotong soft capsule (YDXNT) is a commonly used Chinese herbal preparation for the clinical treatment of coronary disease. However, there is a lack of pharmacokinetic studies on YDXNT, and its active ingredients and their mechanism in the treatment of cardiovascular diseases (CVD) are still unclear. In this study, 15 absorbed ingredients in rat plasma after oral administration of YDXNT were quickly identified based on liquid chromatography tandem quadrupole time-of-flight mass spectrometry (LC-QTOF MS), and then a sensitive and accurate quantitative method based on ultra-high performance liquid chromatography tandem triple quadrupole mass spectrometry (UHPLC-QQQ MS) was established and validated for simultaneous determination of the 15 ingredients of YDXNT in rat plasma, which was then applied to the pharmacokinetic study. Different types of compounds showed various pharmacokinetic characteristics, for instance, ginkgolides with higher maximum plasma concentration (Cmax), flavonoids presenting concentration–time curve with double peaks, phenolic acids with shorter time to reach maximum plasma concentration (Tmax), saponins with long elimination half-life (t1/2) and tanshinones showing fluctuant plasma concentration. Then the measured analytes were regarded as effective compounds and their potential targets and mechanism of action were predicted by constructing and analyzing the compound-target network of YDXNT and CVD. Those potential active compounds of YDXNT interacted with targets such as MAPK1 and MAPK8, and molecular docking showed that the binding free energies of 12 ingredients with MAPK1 were less than −5.0 kcal/mol, indicating that YDXNT intervened in the MAPK signaling pathway to display its therapeutic effect on CVD.

A Rapid Determination of 30 Prohibited Pesticide Residues in Lycii Fructus by UPLC-MS/MS

Prohibited pesticide residues have become one of the main factors affecting the quality and safety of Lycii Fructus, However, rarely studies focus on the rapid determination of these residues. Here, a total of 30 kinds of prohibited pesticide residues were determined by ultra-performance liquid chromatography tandem triple quadrupole mass spectrometry (UPLC-MS/MS) in five different process ways. Pretreatment methods, chromatographic separation and detection conditions in mass spectrometry were all optimized accordingly. Among the five different pretreatment methods, the first and third solid phase extraction failed to provide high recoveries of sulfosulfuron compounds (both lower than 60%). Recovery of chlorphenamidine by the Quick Easy Cheap Effective Rugged and Safe multiresidue method (QuEChERS) was lower than 60%, which did not meet the requirements of trace determination. The concentrations of 30 prohibited pesticides residues treated by straightforward and solid phase extraction showed good linearity in their corresponding ranges, with correlation coefficients over 0.99. The average recoveries of straightforward ranged from 78.13% to 110.9%, while RSD ranged from 1.3% to 16.9%, albeit poor purification was observed. The recovery yield from solid phase extraction was between 67.75% and 103.08% with RSD value from 0.8% to 14.0%, which met the requirements of trace determination, this method has good precision and stability. These results could be employed to other Traditional Chinese Medicines (TCMs) in detecting prohibited pesticide residues.

Plasma pharmacokinetics and pharmacodynamic effects of the 2-benzylbenzimidazole synthetic opioid, isotonitazene, in male rats

Isotonitazene is an illicit synthetic opioid associated with many intoxications and fatalities. Recent studies show that isotonitazene is a potent µ-opioid receptor (MOR) agonist in vitro, but little information is available about its in vivo effects. The aims of the present study were to investigate the pharmacokinetics of isotonitazene in rats, and relate pharmacokinetic parameters to pharmacodynamic effects. Isotonitazene and its metabolites were identified and quantified by liquid chromatography tandem quadrupole mass spectrometry (LC-QQQ-MS). Male Sprague-Dawley rats with jugular catheters and subcutaneous (s.c.) temperature transponders received isotonitazene (3, 10, 30µg/kg, s.c.) or its vehicle. Blood samples were drawn at 15, 30, 60, 120, and 240min post-injection, and plasma was assayed using LC-QQQ-MS. At each blood draw, body temperature, catalepsy scores, and hot plate latencies were recorded. Maximum plasma concentrations of isotonitazene rose in parallel with increasing dose (range 0.2-9.8ng/mL) and half-life ranged from 23.4 to 63.3min. The metabolites 4'-hydroxy nitazene and N-desethyl isotonitazene were detected, and plasma concentrations were below the limit of quantitation (0.5ng/mL) but above the limit of detection (0.1ng/mL). Isotonitazene produced antinociception (ED50 = 4.22µg/kg), catalepsy-like symptoms (ED50 = 8.68µg/kg), and hypothermia (only at 30µg/kg) that were significantly correlated with concentrations of isotonitazene. Radioligand binding in rat brain tissue revealed that isotonitazene displays nM affinity for MOR (Ki = 15.8nM), while the N-desethyl metabolite shows even greater affinity (Ki = 2.2nM). In summary, isotonitazene is a potent MOR agonist whose pharmacodynamic effects are related to circulating concentrations of the parent drug. The high potency of isotonitazene portends substantial risk to users who are exposed to the drug.

Metabolic profiling and pharmacokinetic studies of Baihu-Guizhi decoction in rats by UFLC-Q-TOF–MS/MS and UHPLC-Q-TRAP-MS/MS

BackgroundBaihu-Guizhi decoction (BHGZD) is a well-documented traditional Chinese Medicine (TCM) prescription that has been extensively applied to treating rheumatoid arthritis. Despite of its beneficial outcomes, the chemical constituents of BHGZD have not been fully portrayed and the in vivo absorption, distribution, metabolism, and excretion (ADME) patterns of absorbed components have never been described.MethodsCharacterization of absorbed components and in vivo biotransformation profiling of these feature compounds were based on the ultra-fast liquid chromatography-quadrupole-time-of-flight tandem mass spectrometry (UFLC-Q-TOF-MS/MS). Furthermore, the ultra-high-performance liquid chromatography tandem ion trap quadrupole mass spectrometry (UHPLC-Q-TRAP-MS/MS) system were performed to investigate the pharmacokinetics of active ingredients from BHGZD.ResultsIn this study, we have identified and tentatively characterized 18 feature absorbed prototype and 15 metabolites of BHGZD in rat serum and the in vivo transformation pathways of these absorbed constituents were proposed. Besides, we have established novel quantitative methodology of five crucial components of BHGZD and have monitored the pharmacokinetic behaviors of these constituents spontaneously in rat serum after BHGZD gavage. After rats received two ways of BHGZD gavage, the pharmacokinetic behaviors of each compound exhibited relatively similar behaviors, as evidenced by similar curve track as well as relatively close time to reach maximum concentration (Tmax) and half washout time (T1/2). Whereas the maximum plasma concentration (Cmax) and area under the plasma concentration–time curve (AUC) values of five analytes with multiple dosage were a bit higher than single dosage.ConclusionThis study added knowledge into the material basis and bio-transformation patterns of BHGZD in vivo, which would be of great value for exploring pharmacological effects and mechanism of BHGZD.

Visual authentication of steroidal saponins in Allium macrostemon Bge. and Allium chinense G. Don using MALDI-TOF imaging mass spectrometry and their structure activity relationship

Allium macrostemon Bge. (AMB) and Allium chinense G. Don (ACGD), both named Allii Macrostemonis Bulbus or Xiebai in Chinese, belong to the same genus. They are both used as edible vegetables and medicinal herbs for the treatment of atherosclerosis. So far, comparative analysis of the spatial metabolomes and platelet aggregation function of steroidal saponins has rarely been performed. In this study, high mass resolution matrix-assisted laser desorption/ionization time-of-flight imaging mass spectrometry (MALDI-TOF MSI) were performed on the fresh bulbs of these two herbs for the spatial distribution of steroidal saponins, and ultra-high-performance liquid chromatography tandem triple quadrupole mass spectrometry (UHPLC/TQD-MS) was used to quantify their content levels. Platelet inhibitory activity induced by arachidonic acid, adenosine diphosphate and collagen were fully investigated. A total of 53 differential variables with compounds were identified or tentatively characterized between AMB and ACGD samples by UHPLC/TQD-MS. Furthermore, these steroidal saponins were almost distributed in tunic and outer scale regions of AMB, while they were rich in tunic and whole leaf scale, and rarely in developing flower bud of ACGD bulbs. Quantitative results demonstrated several saponins were the unique components for AMB (macrostemonoside I, timosaponin B-II, macrostemonoside F, etc.) and ACGD (chinenoside I, chinenoside II, chinenoside IV, etc.). Moreover, spirostanol saponins exhibited stronger inhibitory platelet activity than furostanol saponins, and the structure activity relationship was further summarized. In conclusion, high-mass resolution MALDI full-scan MSI provides abundant spatial distribution information of steroidal saponins in AMB and ACGD. And we finished the discussion of their activity characteristics. These findings would benefit the understanding of safety and effectiveness for their edible and medicinal use.

Comprehensive Evaluation of the Quality of Tripterygium Glycosides Tablets Based on Multi-Component Quantification Combined with an In Vitro Biological Assay.

Tripterygium glycosides tablets (TGTs) are widely used in clinical practice to treat rheumatoid arthritis and other autoimmune diseases, with significant beneficial effects but also high toxicity, necessitating rigorous quality evaluation and control. In current study, a rapid resolution liquid chromatography tandem electrospray ionization triple quadrupole mass spectrometry (RRLC–ESI–MS/MS) method was developed and validated for the quantitative analysis of 14 components of ten batches of TGTs produced by different manufacturers, including four diterpenoids, three triterpenoids, and seven sesquiterpene alkaloids. Meanwhile, the NO inhibition effects of these TGTs were evaluated in LPS-induced RAW264.7 cells for their downstream anti-inflammatory activities, as well as their cytotoxicity. The results indicate that the TGTs from different manufacturers showed poor quality consistency, as evidenced by large variations in chemical profiles and biological effects, which may increase the risks associated with clinical use. To improve the quality status of TGTs, it is crucial to identify indicator components whose characterization can accurately reflect the efficacy and toxicity of TGTs from which they were derived. Our study reveals that triptolide, triptoquinone B, celastrol, and demethylzelaysteral considerably contributed to the anti-inflammatory activity and/or cytotoxicity of TGTs, implying that they should be further investigated as candidate indicator components for TGT quality control.

Sample pretreatment and analytical methodology for the determination of antibiotics in swine wastewater and activated sludge.

An analytical method for the simultaneous extraction and determination of eight veterinary antibiotics in swine wastewater and activated sludge was developed and validated based on the instrumental determination by liquid chromatography tandem quadrupole mass spectrometry. Ultrasound-assisted extraction and solid-phase extraction were introduced into the pretreatment procedure of the two complex environmental matrices. The critical steps involved in the sample pretreatment procedure and the instrumental analysis conditions were optimized progressively. Recoveries of the optimized method were good with 75.3-118.2% in wastewater and 82.8-130.1% in sludge. The absolute deviations of methods were lower than 11.7%, presenting a high reproducibility and precision. The limits of quantification for the eight pharmaceuticals in wastewater and sludge were 5-15 ng·L-1 and 2-6 ng·g-1, showing high sensitivity of the methods. The developed method has been successfully applied to evaluate the actual concentration levels of tetracyclines, quinolones, and sulfonamides in actual swine wastewater (maximum detected concentration of 87.377 μg·L-1) and activated sludge (maximum detected concentration of 51242.3 ng·g-1).