Ultrahigh-performance Liquid Chromatography-tandem Mass Spectrometry Research Articles

Simultaneous determination of pyflubumide and its metabolite in vegetables and fruits by ultrahigh performance liquid chromatography-tandem mass spectrometry.

A rapid and cost-effective analytical method based on ultrahigh-performance liquid chromatography-tandem mass spectrometry was designed and verified for simultaneously monitoring the novel acaricide pyflubumide and its metabolite (pyflubumide-des(2-methyl-1oxopropyl)) in vegetables and fruits. After the extraction with acetonitrile, the samples were purified by dispersive solid-phase extraction with multi-walled carbon nanotubes. Detection of the two target analytes was achieved within 3.0min using a positive electrospray ionization mode. The average recovery, intra-day precision, and inter-day precision of the two analytes at three spiked levels (2, 20, and 100 μg/kg) were 75.0-101.0, 0.4-4.4, and 0.6-5.3%, respectively. The limit of quantification of two compounds was 2 μg/kg, which was far below the maximum residue limits of pyflubumide in foods established by Japan and South Korea. Finally, the concentrations of pyflubumide and its metabolite in the samples were 16.6 and 7.8 μg/kg respectively, which verified the practicability and reliability of the method. The method was used to efficiently detect pyflubumide and its metabolite in real samples and was confirmed to be robust and effective for routinely analyzing both pyflubumide and its metabolite in vegetable and fruit samples.

Dissipation behavior, residue transfer, and safety evaluation of chlorantraniliprole and indoxacarb during tea growing and brewing by ultrahigh-performance liquid chromatography-tandem mass spectrometry.

A reliable and simple analytical method was developed and validated to simultaneously determine chlorantraniliprole and indoxacarb in tea using ultrahigh-performance liquid chromatography-tandem mass spectrometry. The average recoveries of chlorantraniliprole were in the range of 86-110%, with the precision of intraday (n = 5) and interday (n = 15) ranging from 1.9 to 8.4% and from 2.4 to 8.8%, respectively. The average recoveries of indoxacarb were in the range 81-105%, with the precision of intraday (n = 5) and interday (n = 15) ranging from 2.0 to 9.8% and from 2.7 to 9.1%, respectively. The limits of quantification (LOQs) were all 0.01mg/kg. The results based on the supervised field trials showed that chlorantraniliprole and indoxacarb in two tea samples followed first-order kinetics models with half-lives of 2.2-4.7days and 2.5-3.5days, which could be regarded as a moderately degrading pesticide. The terminal residues of chlorantraniliprole and indoxacarb in made tea were below 6.7 and 4.5mg/kg, respectively, lower than their corresponding maximum residue limits (MRLs) established by several major countries and organizations (50 and 5mg/kg). The leaching rates of chlorantraniliprole and indoxacarb during the tea brewing ranged from 4.78 to 12.62% and 4.13 to 10.67%, respectively. The chronic intake risk quotient (RQc) values for chlorantraniliprole and indoxacarb were 0.24% and 35.10%, while the acute dietary risk assessment (RQa) value of indoxacarb was 5.8%, which were all much lower than 100%. The results in the present study indicated that the health risk posed by the chlorantraniliprole and indoxacarb mixture pesticides was negligible in tea for consumers at the recommended dosages.

Vascular endothelium as a target for perfluroalkyl substances (PFAs)

IntroductionPerfluoroalkyl substances (PFAs) are ubiquitous, anthropogenic organic compounds that have been linked with cardiovascular disease and cardiovascular risk factors. Older, long-chain PFAs have been phased out due to adverse cardiometabolic health effect and replaced by newer short-chain PFAs. However, emerging research suggests that short-chain PFAs may also have adverse cardiovascular effects. Non-invasive measures of vascular function can detect preclinical cardiovascular disease and serve as a useful surrogate for early CVD risk. We hypothesized that serum concentrations of PFAs would be associated with noninvasive measures of vascular function, carotid-femoral pulse wave velocity (PWV) and brachial artery reactivity testing (BART), in adults with non-occupational exposure to PFAs. MethodsWe measured serum concentrations of 14 PFAs with hybrid solid-phase extraction and ultrahigh-performance liquid chromatography–tandem mass spectrometry in 94 adult outpatients with no known cardiovascular disease. We collected clinical and demographic data; and measured vascular function, PWV and BART, using standard protocols. We assessed associations of individual PFAs with log-transformed BART and PWV using linear regression. We used weighted quantile sum regression to assess effects of correlated PFA mixtures on BART and PWV. ResultsTen PFAs were measured above the limit of detection in >50% of participants. Each standard deviation increase in concentration of perfluoroheptanoic acid (PFHpA) was associated with 15% decrease in BART (95% CI: −28.5, −0.17). The weighted index of a mixture of PFAs with correlated concentrations was inversely associated with BART: each tertile increase in the weighted PFA mixture was associated with 25% lower BART, with 73% of the effect driven by PFHpA. In contrast, no PFAs or mixtures were associated with PWV. ConclusionsSerum concentration of PFHpA, a new, short-chain PFA, was associated with impaired vascular function among outpatients without CVD. Our findings support a potential adverse cardiovascular effect of newer, short-chain PFAs.

A New LC-MS Method for Evaluating the Efficacy of Pesticide Residue Removal from Fruit Surfaces by Washing Agents

Modern agriculture uses pesticides to improve the quality and quantity of crops. However, pesticide residues can remain on agricultural products, posing very serious risks to human health and life. It is recommended to wash fruits and vegetables before consumption. To assess the removal efficacy of pesticide residue, a sensitive and reliable method based on ultrahigh-performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) was developed and optimized for the simultaneous determination of four pesticide residues (acetamiprid, boscalid, pyraclostrobin, and pendimethalin). Isotope-labeled standards were used to validate the method in terms of recovery, linearity, matrix effects, precision, and sensitivity. The mean recovery values for both low-quality control (LQC) and high-quality control (HQC) transitions were in the range of 89–105%, and the intra-day precision was less than 13.7%. The limits of detection (LOD) and quantification (LOQ) were 0.003 mg/kg and 0.01 mg/kg, respectively. The proposed method is suitable for evaluating the quality of detergents for removing pesticide residues from fruit surfaces.

A strategy for the rapid discovery and validation of active diterpenoids as quality markers in different habitats of Langdu using ultrahigh-performance liquid chromatography-tandem mass spectrometry with multivariate statistical analysis.

Langdu, known as a traditional Chinese medicine, was identified as the roots of species of Euphorbia ebracteolata Hayata and Euphorbia fischeriana Steud, displaying anti-tuberculosis activity. To clarify the potent quality markers of Langdu, this research first developed a fast and sensitive ultrahigh-performance liquid chromatography-tandem mass spectrometry method for the quantification of 13 diterpenoids in Langdu. The developed method was further applied in the analyses of 12 authentic E. ebracteolata and E. fischeriana samples collected in northern and southeastern China. Then, the anti-tuberculosis evaluation of 12 batches of Langdu samples was performed in vitro. Finally, partial least squares discrimination analysis was used in the discrimination of E. ebracteolata and E. fischeriana from different origins and processing methods. Jolkinolide A (1), jolkinolide E (3), yuexiandajisu D (6), and ebractenone A (11) were identified as key, potent diterpenoids for the quality control of E. ebracteolata Hayata and E. fischeriana Steud. The present study established a qualitative chemical analysis method for Langdu (E. ebracteolata and E. fischeriana) and suggested the key bioactive components that will improve qualitative control methodology for this important medicine.

Development and validation of a sensitive and reliable targeted metabolomics method for the quantification of cardiovascular disease-related biomarkers in plasma using ultrahigh-performance liquid chromatography-tandem mass spectrometry.

Cardiovascular disease, as a multifactorial disease caused by genetics and environment, has emerged as a leading cause of mortality. The discovery of metabolic biomarkers for the clinical diagnosis, early warning and elucidation of the molecular pathogenesis of cardiovascular disease, using metabolomics, has attracted broad interest. Therefore, this work aimed to develop a sensitive and reliable targeted metabolomics method for the quantification of cardiovascular disease-related biomarkers in plasma. The method was developed and validated using ultrahigh-performance liquid chromatography augmented with tandem mass spectrometry (UHPLC/MS/MS). The LC conditions and MS parameters were optimized using selected reaction monitoring scanning mode to high-throughput and sensitive separation, and could detect 20 metabolic biomarkers in a single experiment. And the linearity, selectivity, accuracy, precision, stability and recovery of the developed method were assessed according to the Bioanalytical Method Validation guidelines of the United States Food and Drug Administration. These quantified metabolic biomarkers are involved in pathways such as aromatic amino acid catabolism (e.g. phenylalanine, tryptophan, tyrosine), trimethylamine N-oxide (TMAO) biosynthesis (e.g. TMAO, choline, carnitine, betaine) and histidine metabolism (e.g. histidine), among others. All analytes exhibited excellent linearities with coefficients of determination greater than 0.99. Accuracies deviated by less than 15% for medium- and high-concentration samples and less than 20% for low-concentration samples, with intra- and inter-day precisions of 1.12-14.12% and 0.30-13.74%, respectively. Recoveries and stabilities also met the analysis requirements of biological samples. The targeted metabolomics method was shown to have a powerful ability to accurately analyze metabolic biomarkers, thereby providing valuable information for large-scale biomarker validation and clarifying the potential material basis of cardiovascular disease for clinical diagnosis or early warning.

Development and validation of a liquid chromeatography-tandem mass spectrometry method for simultaneous quantification of medium- and long-chain saturated fatty acids in hamster plasma samples.

Saturated fatty acids (SFAs) are associated with many diseases in humans. Developing a reliable analytical method to analyze SFAs in plasma is essential to understand their biological activities. An ultrahigh-performance liquid chromatography-tandem mass spectrometry (UHPLC/MS/MS) method has been developed for the quantification of medium- and long-chain SFAs (M/LCSFAs) in hamster plasma. We compared three methods (DOLE, Folch and MTBE) for extracting M/LCSFAs from plasma. The M/LCSFA derivatives were separated using a C18 column. The method was validated and applied to analyze M/LCSFA concentrations in normal-fat diet (NFD) and high-fat diet (HFD) hamster plasma. Among the three extraction methods, the DOLE method had the highest extraction recovery and was simple to operate with a short incubation time. All of the calibration curves exhibited good linear relationships (r ≥ 0.9958). The results for selectivity, accuracy, precision, matrix effects and recovery were all within the acceptance criteria. In HFD hamster plasma, the concentration of M/LCSFAs with even-carbon chain length was significantly increased. A simple, robust and reproducible method for the simultaneous quantification of M/LCSFAs by UHPLC/MS/MS was developed and validated. The method gave successfully quantification of M/LCSFAs in plasma samples from NFD and HFD hamsters.

Simultaneous Determination of Fifteen Polyphenols in Fruit Juice Using Ultrahigh-Performance Liquid Chromatography-Tandem Mass Spectrometry Combining Dispersive Liquid-Liquid Microextraction.

Polyphenols are secondary metabolites of plants and used as effective antioxidants in dietary supplements, whose main sources are fruits, vegetables, and grains. To clarify the content and distribution of polyphenols in different fruit species samples accurately, a rapid and sensitive ultrahigh-pressure liquid chromatography-electrospray ionization-tandem mass spectrometry (UPLC-ESI-MS/MS) method combining dispersive liquid-liquid microextraction (DLLME) was developed for quantitative determination of fifteen polyphenol compounds in fruit juice. In this method, the targets were first extracted from 1 g of fruit juice sample using 10 mL of 80% ethanol solution by ultrasonic-assisted extraction (UAE). Then, 1.0 mL of UAE extracted solution, 60 μL of n-octanol and 2.0 mL of H2O were performed in the following DLLME procedure. A C18 reversed-phase column, ZORBAX SB (100 × 4.6 mm, 3.5 μm), was proposed under gradient elution with 0.1% formic acid aqueous solution and methanol mobile phases for the determination of 15 polyphenols, allowing us to obtain polyphenolic profiles in less than 23.0 min. Under the optimum conditions, the enrichment factors ranged from 162 to 194. The results showed that the 15 polyphenols had linear correlation coefficients (R2) more than 0.99. The limits of detection (LODs) were between 18.3 and 103.5 ng/g, and the average recoveries were between 96.9 and 116.3% with interday relative standard deviations (RSDs) ranging from 4.4 to 8.2% in all cases. The method was successfully applied to the analysis of real fruit juice samples and presented itself as a simple, rapid, practical, and environment-friendly technique.

Determination of higenamine and tretoquinol in spices by solid phase extraction-isotope internal standard-high performance liquid chromatography-tandem mass spectrometry

A method was developed and validated for the determination of two plant-derived doping agents, higenamine (HG) and tretoquinol (TQ), in 26 kinds of spices. This was undertaken using ultrahigh-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) and isotope internal standards. The samples were extracted with ethanol containing 0.5% formic acid and purified using an Oasis MCX solid phase extraction cartridge. Subsequently, a C18 column was used for chromatographic separation using methanol and 0.05% formic acid aqueous solution as the mobile phase. UPLC-MS/MS in positive ESI and multiple reaction monitoring mode with HG-D4 and TQ-D9 as the internal standards were used for detection and quantification of analytes. The method was successfully calibrated in the range of 0.2–50 ng mL−1. The limit of detections (LODs) and limit of quantifications (LOQs) of HG were 0.57–0.88 µg kg−1 and 1.80–2.72 µg kg−1, respectively; the LODs and LOQs of TQ were 0.39–0.58 µg kg−1 and 1.27–1.88 µg kg−1, respectively. The average recoveries of the analytes fortified at four levels ranged from 77.1% to 98.7%, with a relative standard deviation < 15%. The proposed method has been successfully used to monitor real samples, and shown to be sensitive, rapid, and convenient. Hence, this method could be used for regulatory purposes to screen for the presence of HG and TQ in various spices.

Association Between Plasma L-Carnitine and Cognitive Impairment in Patients with Acute Ischemic Stroke.

L-carnitine has been shown to exert neuroprotective effects on cerebral ischemia, mainly by improving mitochondrial function and reducing inflammation. L-carnitine supplementation has also been promoted to enhance cognitive function. However, the relationship between L-carnitine and cognitive impairment after ischemic stroke has seldom been studied. We aimed to evaluate the association between plasma L-carnitine and poststroke cognitive impairment. The study sample population was drawn from the China Antihypertensive Trial in Acute Ischemic Stroke. Plasma L-carnitine were measured at baseline in 617 patients with ischemic stroke using ultrahigh-performance liquid chromatography-tandem mass spectrometry. Cognitive function was evaluated using the Montreal Cognitive Assessment at 3-month follow-up after ischemic stroke. Plasma L-carnitine were inversely associated with cognitive impairment at 3 months after ischemic stroke, and the adjusted odds ratio (95% CI) for the highest versus lowest quartiles of L-carnitine was 0.60 (0.37, 0.98; p for trend = 0.04). Each 1-SD increase in log-transformed L-carnitine concentration was significantly associated with a 15% (95% CI: 1%, 29%) reduction in the risk of cognitive impairment after stroke. The addition of L-carnitine to the model including conventional risk factors significantly improved the risk reclassification for cognitive impairment (net reclassification improvement: 17.9%, integrated discrimination improvement: 0.8%; both p < 0.05). Furthermore, joint effects of L-carnitine and inflammation markers were observed, and patients with higher L-carnitine and a lower inflammatory status simultaneously had the lowest risk of poststroke cognitive impairment. The present study provided prospective evidence on the inverse association between plasma L-carnitine and cognitive impairment after ischemic stroke.

Exploration of Human Serum Lipoprotein Supramolecular Phospholipids Using Statistical Heterospectroscopy in n-Dimensions (SHY-n): Identification of Potential Cardiovascular Risk Biomarkers Related to SARS-CoV-2 Infection.

SARS-CoV-2 infection causes a significant reduction in lipoprotein-bound serum phospholipids give rise to supramolecular phospholipid composite (SPC) signals observed in diffusion and relaxation edited 1H NMR spectra. To characterize the chemical structural components and compartmental location of SPC and to understand further its possible diagnostic properties, we applied a Statistical HeterospectroscopY in n-dimensions (SHY-n) approach. This involved statistically linking a series of orthogonal measurements made on the same samples, using independent analytical techniques and instruments, to identify the major individual phospholipid components giving rise to the SPC signals. Thus, an integrated model for SARS-CoV-2 positive and control adults is presented that relates three identified diagnostic subregions of the SPC signal envelope (SPC1, SPC2, and SPC3) generated using diffusion and relaxation edited (DIRE) NMR spectroscopy to lipoprotein and lipid measurements obtained by in vitro diagnostic NMR spectroscopy and ultrahigh-performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS). The SPC signals were then correlated sequentially with (a) total phospholipids in lipoprotein subfractions; (b) apolipoproteins B100, A1, and A2 in different lipoproteins and subcompartments; and (c) MS-measured total serum phosphatidylcholines present in the NMR detection range (i.e., PCs: 16.0,18.2; 18.0,18.1; 18.2,18.2; 16.0,18.1; 16.0,20.4; 18.0,18.2; 18.1,18.2), lysophosphatidylcholines (LPCs: 16.0 and 18.2), and sphingomyelin (SM 22.1). The SPC3/SPC2 ratio correlated strongly (r = 0.86) with the apolipoprotein B100/A1 ratio, a well-established marker of cardiovascular disease risk that is markedly elevated during acute SARS-CoV-2 infection. These data indicate the considerable potential of using a serum SPC measurement as a metric of cardiovascular risk based on a single NMR experiment. This is of specific interest in relation to understanding the potential for increased cardiovascular risk in COVID-19 patients and risk persistence in post-acute COVID-19 syndrome (PACS).

Direct multiclass desorption electrospray ionization-tandem mass spectrometry method for the analysis of sleep inducers and ototoxic drugs in dried blood spots.

An unconventional and innovative approach for the quantitative determination of 11 ototoxic and narcoleptic drugs in whole blood is described. The multiclass method allows the inclusion of the most widespread drugs on the market (antihistamines, antidepressants, antihypertensives, anxiolytics, opioids, Z-drugs) responsible for 10% of occupational accidents. The developed procedure involved the use of the desorption electrospray ionization (DESI) interface for the direct analysis of dried blood spots (DBS). All the issues strictly connected to the chemical-physical characteristics of DBS and DESI (sample inhomogeneity, DBS support, DESI geometry and solvent) were carefully evaluated and innovative strategies were applied. Haematocrit was managed using a small and measured volume of blood (2μL) with analysis of the entire DBS. The proposed method was fully validated in terms of limits of detection, limits of quantitation (LOQs; between 60 pg/mm2 and 1.6ng/mm2 ), linearity (one order of magnitude starting from LOQs) and inter- and intra-day precision (on three levels, with relative standard deviation values not exceeding 17%). Accuracy was calculated by comparison with an ultrahigh-performance liquid chromatography-tandem mass spectrometry method (suitable also as a confirmatory method). Results showed a surprising sensitivity, demonstrating that this procedure could be suitable for applications in various fields, e.g. forensic analysis. Moreover, as a collateral benefit, it was discovered that the method is able to analyse very light traces left on plastic and glass surfaces by detached dried blood.

Non-targeted Metabolomics Profiling of Plasma Samples From Patients With Major Depressive Disorder.

BackgroundMajor depressive disorder (MDD) is a neuropsychiatric disorder caused by multiple factors. Although there are clear guidelines for the diagnosis of MDD, the direct and objective diagnostic methods remain inadequate thus far.MethodsThis study aims to discover peripheral biomarkers in patients with MDD and promote the diagnosis of MDD. Plasma samples of healthy controls (HCs, n = 52) and patients with MDD (n = 38) were collected, and then, metabolism analysis was performed using ultrahigh-performance liquid chromatography–tandem mass spectrometry (LC–MS/MS). Heatmap analysis was performed to identify the different metabolites. Meanwhile, receiver operating characteristic (ROC) curves of these differential metabolites were generated.ResultsSix differential metabolites were found by LC–MS/MS analysis. Three of these were increased, including L-aspartic acid (Asp), diethanolamine, and alanine. Three were decreased, including O-acetyl-L-carnitine (LAC), cystine, and fumarate. In addition, LAC, Asp, fumarate, and alanine showed large areas under the curve (AUCs) by ROC analysis.ConclusionThe study explored differences in peripheral blood between depressed patients and HCs. These results indicated that differential metabolites with large AUCs may have the potential to be promising biomarkers for the diagnosis of MDD.

Risk to Public Health Regarding Doxycycline Residues in Chicken Claws.

Doxycycline residues in claws may pose a potential risk to humans. A study with broiler chickens was performed to find the concentrations of doxycycline in claws after treatment. For the quantification of the antibiotic of interest in claws, an ultrahigh-performance liquid chromatography-tandem mass spectrometry method was developed. Doxycycline was detectable at 3043 μg/kg at sub-therapeutic treatment, 223 μg/kg after therapeutic doses, and 14 μg/kg after spray application on the last day of the experiment (day 22). Almost 70 days is required for the concentration of doxycycline to reach zero. The obtained results show that monitoring of doxycycline in claws should be implemented.

Identification of Benzophenone Analogs in Rice Cereal through Fast Pesticide Extraction and Ultrahigh-Performance Liquid Chromatography-Tandem Mass Spectrometry.

A fast, robust, and sensitive analytical method was developed and validated for the simultaneous identification of benzophenone (BP) and nine BP analogs (BP-1, BP-2, BP-3, BP-8, 2-hydroxybenzophenone, 4-hydroxybenzophenone, 4-methylbenzophenone [4-MBP], methyl-2-benzoylbenzoate, and 4-benzoylbiphenyl) in 25 samples of rice cereal. Fast pesticide extraction (FaPEx) coupled with ultrahigh-performance liquid chromatography–tandem mass spectrometry was applied. The developed method exhibited satisfactory linearity (r > 0.997), favorable recoveries between 71% and 119%, and a limit of detection ranging from 0.001 to 0.5 ng/g. The detection frequencies of BP, 4-MBP, and BP-3 were 100%, 88%, and 52%, respectively. BP had higher geometric levels, with a mean of 39.8 (19.1–108.9) ng/g, and 4-MBP had low levels, with a mean of 1.9 (1.3–3.3) ng/g. The method can be applied to routine rice cereal analysis at the nanogram-per-gram level. For infants aged 0–3 years, the hazard quotients of BP and 4-MBP were lower than one, and the margin of exposure for BP was higher than 10,000, suggesting that rice cereal consumption poses no health concern for Taiwanese infants.

Diet-Induced High Serum Levels of Trimethylamine-N-oxide Enhance the Cellular Inflammatory Response without Exacerbating Acute Intracerebral Hemorrhage Injury in Mice.

Trimethylamine-N-oxide (TMAO), an intestinal flora metabolite of choline, may aggravate atherosclerosis by inducing a chronic inflammatory response and thereby promoting the occurrence of cerebrovascular diseases. Knowledge about the influence of TMAO-related inflammatory response on the pathological process of acute stroke is limited. This study was designed to explore the effects of TMAO on neuroinflammation, brain injury severity, and long-term neurologic function in mice with acute intracerebral hemorrhage (ICH). We fed mice with either a regular chow diet or a chow diet supplemented with 1.2% choline pre- and post-ICH. In this study, we measured serum levels of TMAO with ultrahigh-performance liquid chromatography-tandem mass spectrometry at 24 h and 72 h post-ICH. The expression level of P38-mitogen-protein kinase (P38-MAPK), myeloid differentiation factor 88 (MyD88), high-mobility group box1 protein (HMGB1), and interleukin-1β (IL-1β) around hematoma was examined by western blotting at 24 h. Microglial and astrocyte activation and neutrophil infiltration were examined at 72 h. The lesion was examined on days 3 and 28. Neurologic deficits were examined for 28 days. A long-term choline diet significantly increased serum levels of TMAO compared with a regular diet at 24 h and 72 h after sham operation or ICH. Choline diet-induced high serum levels of TMAO did not enhance the expression of P38-MAPK, MyD88, HMGB1, or IL-1β at 24 h. However, it did increase the number of activated microglia and astrocytes around the hematoma at 72 h. Contrary to our expectations, it did not aggravate acute or long-term histologic damage or neurologic deficits after ICH. In summary, choline diet-induced high serum levels of TMAO increased the cellular inflammatory response probably by activating microglia and astrocytes. However, it did not aggravate brain injury or worsen long-term neurologic deficits. Although TMAO might be a potential risk factor for cerebrovascular diseases, this exploratory study did not support that TMAO is a promising target for ICH therapy.

Magnetic mesoporous material derived from MIL-88B modified by l-alanine as modified QuEChERS adsorbent for the determination of 6 pesticide residues in 4 vegetables by UPLC-MS/MS

More and more attention has been paid to the improved QuEChERS (quick, easy, cheap, effective, rugged and safe) method in dealing complex sample matrices, especially for the study of QuEChERS adsorbents. In this study, a magnetic mesoporous material, which was derived from MIL-88B modified by l-alanine, was synthesized as modified QuEChERS adsorbents for the simultaneous determination of multiple pesticides (Methomyl, Isoprocarb, Carbofuran, 3-Hydroxycarbofuran, Acetamiprid, Imidacloprid) in Chinese cabbage, celery, long bean and leek. The prepared magnetic adsorbents can effectively remove interfering substances from the sample, and the proposed modified QuEChERS method can reduce sample pretreatment time via an external magnetic field. To achieve the best performance of QuEChERS method, the clean-up time and amount of QuEChERS adsorbents were investigated. Under the optimized conditions, a simple, rapid and sensitive method for the determination of 6 pesticide residues in vegetables was established by coupling the modified QuEChERS to ultrahigh-performance liquid chromatography-tandem mass spectrometry. Excellent sensitivity (The limit of detection for the 6 pesticides ranged from 0.001 to 0.020 µg kg−1), satisfactory linearity (r2 ≥ 0.9952), good recovery (73.9–107.7%) and good precision (3.6–16.9% for intraday relative standard deviation, 0.5–15.0% for interday relative standard deviation) were obtained. Compared with traditional QuEChERS method, the proposed method is simple, cost-effective, and efficient, which indicates that the method can be used to detect carbamate and neonicotinoid pesticides in real samples and provide an excellent pretreatment technique for the detection of trace multi-analytes from complex substrates.

Metabolome alterations in Clonorchis sinensis after treatment with tribendimidine and praziquante in vivo

Tribendimidine (TBD) is a broad-spectrum anthelmintic drug that is also significantly effective in treating clonorchiasis. In this study, the altered metabolomes of Clonorchis sinensis (C. sinensis) in rats after TBD administration were quantified by using ultrahigh-performance liquid chromatography-tandem mass spectrometry (UHPLC–MS/MS) and gas chromatography-mass spectrometry (GC–MS) to explore the possible active sites of TBD against clonorchiasis through altered metabolites and metabolic pathway analysis, and the results are expected to provide a target for the future design of anti-Clonorchis sinensis drugs. The worm burden reduction rate and scanning electron microscopy demonstrated that praziquantel (PZQ, positive control drug) and TBD had significant effects on C. sinensis in rats after treatment at a single dose of 200 mg/kg for 24 h. For the MS-based metabolomic analysis, a total of 173 standard metabolites (126 amino acids, 10 phospholipids and 37 fatty acids) were utilized as a reference metabolite database for metabolome identification. In total, 32 amino acids, 71 phospholipids and 27 fatty acids were detected in the C. sinensis of each group. Among these metabolites, 10 amino acids were significantly decreased in both drug-treated groups. Four lysophosphatidyl cholines (LPCs), six lysophosphatidyl ethanolamines (LPEs) and one phosphatidyl inositol (PI) were significantly increased after treatment with TBD. There were no significant changes in fatty acids among the control group and the two drug-treated groups. The results indicated that TBD administration caused a decrease in amino acids involved in the metabolic pathways of energy consumption and an increase in lysophospholipids, which are the hydrolysis products of phospholipase2 (PLA2) in the phospholipid metabolic pathways. The increased lysophospholipid content can destroy the cell membrane, increase membrane permeability, and even cause exposure to internal antigens that can be attacked by host antibodies. Perhaps the destroyed membrane, the exposed internal antigens and the consumed energy are the cause of the damage and death of C. sinensis after TBD administration. This is an interesting problem that can be examined in future research.

Metabolic Effects of Violet Light on Spoilage Bacteria from Fresh-Cut Pakchoi during Postharvest Stage.

Pakchoi (Brassica rapa L. Chinensis) is an important vegetable in Asia. Pseudomonas palleroniana is one of the specific spoilage organisms (SSOs) of fresh-cut pakchoi. The purpose of this study was to investigate changes to the endogenous metabolic spectrum of violet light (405 nm) with regard to food spoilage bacteria from fresh-cut pakchoi using ultrahigh-performance liquid chromatography-tandem mass spectrometry. In this study, P. palleroniana samples were treated with violet light at 4 °C, and the maximum dose was 133.63 J/cm2. The results revealed that 153 metabolites and 83 pathways significantly changed compared to the control group, which indicated that light treatment may lead to ROS accumulation in cells, inducing oxidative stress and the excessive consumption of ATP. However, the increased content of aromatic amino acids and the decreased anabolism of some amino acids and nucleotides might be a form of self-protection by reducing energy consumption, thus contributing to the improvement of the tolerance of cells to illumination. These results provide new insights into the antibacterial mechanism of P. palleroniana with regard to metabolism.

Metabolite Signature of Physical Activity and the Risk of Type 2 Diabetes in 7271 Men.

Large population-based studies investigating the association of physical activity (PA) with the metabolite signature contribute significantly to the understanding of the effects of PA on metabolic pathways associated with the risk of type 2 diabetes. Our study included 8749 Finnish men without diabetes at baseline recruited from the Metabolic Syndrome in Men (METSIM) cohort. We used a questionnaire to measure leisure-time PA. Metabolites were measured in 7271 men as a part of Metabolon’s untargeted Discovery HD4 platform using ultrahigh-performance liquid chromatography–tandem mass spectrometry. We found 198 metabolites significantly associated with PA. Several of these metabolites were novel including especially steroids, amino acids, imidazoles, carboxylic acids, and hydroxy acids. Increased PA was significantly associated with high levels of choline plasmalogens, lysophosphatidylcholines, polyunsaturated fatty acids, carotenoids, long chain acylcarnitines, imidazoles, bilirubins, aryl sulfates, hydroxy acids, indolepropionate, and indolelactate. Several of these metabolites have been previously associated with a decreased risk of type 2 diabetes and with a healthy diet. Our population-based study shows that the metabolite signature of increased PA includes multiple metabolic pathways and is associated with better adherence to a healthy lifestyle.