Linear Ion Trap Tandem Mass Research Articles

Plasma metabolomics identifies S-adenosylmethionine as a biomarker and potential therapeutic target for vascular aging in older adult males

Brachial-ankle pulse wave velocity (baPWV) is a noninvasive index of vascular aging. However, the metabolic profile underlying vascular aging has not yet been fully elucidated. The current study aimed to identify circulating markers of vascular aging as assessed by baPWV and to elucidate its mechanism from a metabolomic perspective in older adults. A total of 60 and 61 Chinese male participants aged ≥80 years were recruited to the metabolome and validation cohorts, respectively. The baPWV of participants was measured using an automatic waveform analyzer. Plasma metabolic profile was investigated using ultra-performance liquid chromatography coupled with triple quadrupole linear ion trap tandem mass spectrometry. Orthogonal partial least squares (OPLS) regression modeling established the association between metabolic profile and baPWV to determine important metabolites predictive of vascular aging. Additionally, an enzyme-linked immunosorbent assay was employed to validate the metabolites in plasma and culture media of vascular smooth muscle cells in vitro. OPLS modeling identified 14 and 22 metabolites inversely and positively associated with baPWV, respectively. These 36 biomarkers were significantly enriched in seven metabolite sets, especially in cysteine and methionine metabolism (p <0.05). Notably, among metabolites involved in cysteine and methionine metabolism, S-adenosylmethionine (SAM) level was inversely related to baPWV, with a significant correlation coefficient in the OPLS model (p <0.05). Furthermore, the relationship between SAM and vascular aging was reconfirmed in an independent cohort and at the cellular level in vitro. SAM was independently associated with baPWV after adjustments for clinical covariates (β = −0.448, p <0.001) in the validation cohort. In summary, plasma metabolomics identified an inverse correlation between SAM and baPWV in older males. SAM has the potential to be a novel biomarker and therapeutic target for vascular aging.

Quality evaluation of Lysimachiae Herba from different habitats based on simultaneous determination of multiple bioactive constituents combined with multivariate statistical analysis

A method based on ultra-high performance liquid chromatography coupled with triple quadrupole linear ion trap-tandem mass spectrometry(UHPLC-QTRAP-MS/MS) was developed for the simultaneous determination of 41 bioactive constituents of flavonoids, organic acids, nucleosides, and amino acids in Lysimachiae Herba. The content of multiple bioactive constituents was compared among the samples from different habitats. The chromatographic separation was performed in a Waters XBridge®C_(18) column(4.6 mm×100 mm, 3.5 μm) at 30 ℃. The gradient elution was performed with 0.4% methanol(A)-formic acid water(B) as the mobile phase at a flow rate of 0.8 mL·min~(-1), and the multiple-reaction monitoring(MRM) mode was adopted. According to the content of 41 constituents, hierarchical cluster analysis(HCA), orthogonal partial least squares discriminant analysis(OPLS-DA), and gray relational analysis(GRA) were perfomed to comprehensively evaluate the samples from different habitats. The results showed that the 41 constituents exhibited good linear relationship within the tested concentration ranges, with the correlation coefficients(r) greater than 0.999 4. The method featured good precision, repeatability, and stability with the relative standard deviations(RSDs) less than 5.0%. The average recoveries of the 41 constituents ranged from 98.06% to 101.9%, with the RSDs of 0.62%-4.6%. HCA and OPLS-DA separated 48 batches of Lysimachiae Herba samples from different habitats into three categories: the producing areas in Sichuan and Chongqing, the producing areas in Jiangsu, Zhejiang, and Jiangxi, and the producing areas in Guizhou. The content of 41 constituents varied among the Lysimachiae Herba samples from different habitats. The GRA results revealed that the Lysimachiae Herba sample from Nanchong City, Sichuan Province had the best comprehensive quality. The method developed in this study was accurate and reliable and thus can be used for comprehensive evaluation of Lysimachiae Herba quality and provide basic information for the selection of habitats.

Novel Isotope Dilution High-Performance Liquid Chromatography Quadrupole–Linear Ion Trap Tandem Mass Spectrometry Method for the Determination of Five Steroid Hormones in Human Serum

Accurate measurement of endogenous steroid hormones in serum is a powerful tool for understanding the status of human adrenal diseases. Isotope dilution–liquid chromatography–tandem mass spectrometry is the most commonly used method for determination of steroids in serum. In this study, we used a laboratory-constructed quadrupole-linear ion trap (Q-LIT) tandem mass spectrometer to develop a new method for the quantification of five steroid hormones in serum. A simple and efficient pretreatment was improved, wherein the serum was extracted once by a mixed solvent of 1.0 mL of ethyl acetate and n-hexane. Using the optimized method, the regression coefficients of the calibration curves were all higher than 0.99, the limits of detection were from 0.31 to 1.25 ng mL−1, and the limits of quantification were between 1.00 and 2.50 ng mL−1. The intra-day (n = 3) relative standard deviations ranged from 4.24% to 13.79%, and the inter-day (n = 3) relative standard deviations from 3.99% to 11.43%. After internal standard correction, the relative recoveries of all steroids were from 86.08% to 106.60%. Twenty-two serum samples were analyzed by Q-LIT, which was compared with commercial triple quadrupole mass spectrometer. The results of the instruments had high consistency. Therefore, Q-LIT accurately quantified steroid hormones in human samples and may be used for clinical diagnosis and monitoring of hormone-dependent diseases.

Pharmacokinetics and tissue distribution of 12 major active components in normal and chronic gastritis rats after oral administration of Weikangling capsules

Ethnopharmacological relevanceWeikangling Capsules (WKLCs) have been used in the clinic for the treatment of gastrointestinal disorders for more than 30 years. However, the pharmacokinetic characteristics and tissue distribution of its major bioactive components in rats under different physiological and pathological conditions are unclear. Aim of the studyIn this study, we aimed to clarify the differences in pharmacokinetic parameters and tissue distribution of the major active components in WKLCs under physiological and pathological states. Materials and methodNormal and ethanol-induced chronic gastritis rats received 2.16 g/kg WKLCs by gavage, and urine, feces, plasma, and tissue (heart, liver, spleen, lung, kidney, stomach, and small intestine) samples were obtained. The active components in urine, feces and plasma were detected by ultra-high-performance liquid chromatography coupled with quadrupole-time-of-flight mass spectrometry (UHPLC-Q-TOF-MS/MS). A rapid and sensitive analytical method, ultra-high-performance liquid chromatography coupled with triple-quadrupole linear ion-trap tandem mass spectrometry (UHPLC-QTRAP-MS/MS), was established and validated to clarify and compare the pharmacokinetics and tissue distribution of the major active components in normal and chronic gastritis rats. ResultsA total of 36 chemical components in the feces, urine, and plasma of chronic gastritis rats were identified by UHPLC-Q-TOF-MS/MS. Among them, 20 were the prototype components of WKLCs, and 16 were metabolites. The pharmacokinetic characteristics and tissue distribution of 12 prototype components were successfully analyzed by UHPLC-QTRAP-MS/MS. The pharmacokinetic results showed that the Cmax, AUC0-t, and AUC0-∞ of paeoniflorin, glycyrrhizic acid, and glycyrrhetinic acid were distinctly higher than those of the other components in normal and chronic gastritis rats. Compared to normal rats, the Cmax, AUC0-t, and AUC0-∞ of albiflorin, liquiritin apioside, liquiritin, isoliquiritin, ononin, isoliquiritigenin, dactylorhin A, and glycyrrhizic acid were significantly increased in chronic gastritis rats (P < 0.05), while the Cmax, AUC0-t and AUC0-∞ of militarine and liquiritigenin had significantly lower decreases in chronic gastritis rats (P < 0.05). The results of the tissue distribution showed that the 12 components were widely distributed in the heart, liver, spleen, lung, kidney, stomach, and small intestine of rats, of which the liver, kidney, stomach, and small intestine were the main accumulative organs. Compared with normal rats, the concentrations of 12 components in the liver, kidney, stomach, and small intestine of chronic gastritis rats were widely higher than those of normal rats at the same time points. ConclusionThe pharmacokinetic characteristics and tissue distribution of 12 active components of WKLCs were comprehensively characterized and elucidated in normal and chronic gastritis rats. These findings laid a solid foundation for revealing the pharmacodynamic material basis of WKLCs in treating gastrointestinal disorders.

Simultaneous quantification of multiple active components of the ginkgo ketoester tablet when combined with donepezil in four biological matrices from an Alzheimer’s animal model: Evaluation of drug distribution patterns in vivo

Ginkgo ketoester tablets (GT) and donepezil are clinically used in combination to treat Alzheimer’s disease (AD). This study aimed to investigate the anti-dementia effects of two drugs alone and in combination by monitoring the distribution patterns of their active components in different biological matrices. A practical analytical method was developed for simultaneously quantifying 38 active compounds in different matrices at trace levels using ultra-performance liquid chromatography coupled with triple-quadrupole linear ion-trap tandem mass spectrometry (UHPLC-MS2). Under optimized conditions, good chromatographic separation of the 38 target compounds was achieved within 14 min, with acceptable linearity, limits of detections and quantifications, precision, stability, and extraction recovery and matrix effects. The developed analytical method quantified the 38 active components in the brain, plasma, intestine, and intestinal contents of AD mice treated with GT alone, donepezil alone, and a combination of the two drugs. The result showed that the combination group had enhanced anti-dementia active compounds and reduced levels of toxic compounds entering the targeted tissues. These findings support the combined use of GT and donepezil for increasing anti-dementia treatment efficiency and reducing toxicity. The proposed UHPLC-MS2 strategy could be used to monitor the levels of active compounds from different biological matrices in future studies.

Simultaneous determination of the residues of anesthetics and sedatives in fish using LC-QLIT-MS/MS combined with DSPE

Liquid chromatography coupled with quadrupole linear ion trap tandem mass spectrometry (LC-QLIT-MS/MS) technology operated in electrospray ionization (ESI) was developed for tracing anesthetic (AETs) and sedatives (SDTs) in fish. Sampling procedure was achieved by using acetonitrile extraction followed by dispersive solid phase extraction (DSPE) clean-up. Under the optimized laboratory conditions, reliable qualitative confirmation was obtained through the multiple reaction monitoring-information dependent acquisition-enhanced product ion (MRM-IDA-EPI) mode. Results indicated a favorable linear in the concentration range of 1–100 μg∙kg−1 (0.1–10 μg∙kg−1 for MS-222), with regression coefficient not less than 0.9997. The detection limit ranges from 0.03 to 0.4 μg∙kg−1 (S/N = 3). The validated method was applied to determine AETs and SDTs in fish with satidfied recoveries of 86.3 %–111.7 % and the relative standard deviations (RSD) of 1.9 %–8.9 % (n = 6). Practical samples analysis indicated that the proposed method is simple, rapid, sensitive and accurate for identification of AETs and SDTs.

Quantitative analysis of nutrients for nucleosides, nucleobases, and amino acids hidden behind five distinct regions-derived Poria cocos using ultra-performance liquid chromatography coupled with triple-quadrupole linear ion-trap tandem mass spectrometry.

Poria cocos is an edible fungus used as a health product and traditional Chinese medicinal preparation. Nevertheless, little is known about its nutrients. In this study, ultra-high performance liquid chromatography coupled with triple-quadrupole linear ion-trap tandem mass spectrometry was conducted to quantify nucleosides, nucleobases, and amino acids in 32 batches of Poria cocos samples collected from Anhui, Sichuan, Hubei, Hunan, and Guizhou. Subsequently, the linearity, precision, repeatability, stability, and recovery of our methods were validated. Samples from different regions were clearly separated by partial least squares discriminant analysis and cluster analysis. Our results suggested that Poria cocos samples from different geographical environments differed in nucleosides, nucleobases, and amino acids. The plot of variable importance for projection disclosed differential compositions of L-Leucine, Uridine, L-Asparagine, L-Glutamine, L-phenylalanine, L-Ornithine monohydrochloride, L-Hydroxyproline, Taurine, and Inosine in Poria cocos from five regions. We found the highest content of total analytes, total amino acids, and total non-essential amino acids in Poria cocos from Anhui, total essential amino acids in the Sichuan samples, and total nucleosides in the Hunan samples. Overall, we determined the content of Poria cocos-derived nucleosides, nucleobases, and amino acids, providing the foothold for further chemical mining and use of Poria cocos.

Simultaneous Determination of 32 Pyrrolizidine Alkaloids in Two Traditional Chinese Medicine Preparations by UPLC-MS/MS.

Pyrrolizidine alkaloids (PAs) constitute a class of phytotoxin which demonstrates strong hepatotoxicity. In China, many plants containing PAs are used as traditional medicines or medicinal preparations, which could harm human health and safety. Xiaoyao Tablet (XYT) is an antidepressant drug registered in the European Union (EU), Compound Danshen Dropping Pills (CDDP) is a commonly used drug for coronary heart disease, and phase III clinical study is ongoing in the United States. The purpose of this study is to provide data to support the use of Chinese medicine preparations internationally and to establish analytical methods for 32 PAs in XYT and CDDP. The extraction parameters that were optimized include solid-phase extraction (SPE) cartridge, extraction method, and extraction solvent. Then ultra-performance liquid chromatography coupled with triple-quadrupole linear ion-traptandem mass spectrometry (UPLC-MS/MS) was developed to effectively and efficiently quantify the 32 PAs of the XYT and CDDP. The analytical methods for XYT and CDDP were verified respectively. For XYT, the analytical method for 32 PAs was linear, and the correlation coefficient r was greater than 0.994; the recovery (REC%) at 10–2000 μg/kg was 73.3%–118.5%, and the relative standard deviation (RSD%) was 2.1%–15.4%. The CDDP REC% was 71.8%–112.0%, and the RSD% was 2.0%–17.1%. This study provides technical and data support for the registration of Chinese patented medicines in the EU, controls quality and ensures safety, and is committed to the internationalization and standardization of Chinese patented medicines.

Simultaneous Determination and Health Risk Assessment of Four High Detection Rate Pesticide Residues in Pu'er Tea from Yunnan, China.

Four pesticides with a high detection rate in Pu’er tea have been determined by a QuEChERS (quick, easy, cheap, effective, rugged, safe) method with multiwalled carbon nanotubes (MWCNTs), and combined ultrahigh-performance liquid chromatography–triple quadrupole linear ion trap-tandem mass spectrometry (UHPLC-QTRAP-MS/MS). MWCNs have been compared with other common purification materials, and found to be superior. The matrix effect was systematically studied, and the results show that the MWCNs can quickly and effectively reduce matrix interference values, which were in the range from −17.8 to 13.8. The coefficients (R2) were greater than 0.99, with the limit of quantification ranging from 0.1 to 0.5 μg/kg, and the recovery rate ranging from 74.8% to 105.0%, while the relative standard deviation (RSD) ranged from 3.9% to 6.6%. A total of 300 samples, taken from three areas in which Yunnan Pu’er tea was most commonly produced, tested for four pesticides. The results show that the detection rate of tolfenpyrad in Pu’er tea was 35.7%, which is higher than other pesticides, and the lowest was indoxacarb, with 5.2%. The residual concentrations of chlorpyrifos, triazophos, tolfenpyrad and indoxacarb ranged from 1.10 to 5.28, 0.014 to 0.103, 1.02 to 51.8, and 1.07 to 4.89 mg/kg, respectively. By comparing with China’s pesticide residue limits in tea (GB 2763-2021), the over standard rates of chlorpyrifos, tolfenpyrad, and indoxacarb were 4.35%, 0.87% and 0%, respectively. The risk assessment result obtained with the hazard quotient (HQ) method shows that the HQ of the four pesticides was far less than one, indicating that the risk is considered acceptable for the four pesticides in Pu’er tea. The largest HQ was found for tolfenpyrad, 0.0135, and the smallest was found for indoxacarb, 0.000757, but more attention should be paid to tolfenpyrad in daily diets in the future, because its detection rate, and residual and residual median were all relatively high.

Sample preparation and antibiotic quantification in vinasse generated from sugarcane ethanol fuel production

Vinasse - liquid organic residue derived from the production of sugarcane ethanol fuel, has been applied as soil amendment via fertigation for decades in Brazil. This organic residue is an important source of nutrients and water for sugarcane crops. Through fertigation, approximately 400 billion liters of vinasse are recycled annually. Despite the economic and agronomic importance of this practice, vinasse-based fertigation can be a source of antibiotic contamination in the environment. The present work reports the application of solid phase extraction (SPE), salting-out liquid-liquid extraction (SALLE), and on-line solid phase extraction (on-line SPE) as sample preparation techniques for the analysis of the following antibiotics (contaminants) in vinasse sample: monensin, penicillin G, virginiamycin M1, virginiamycin S1, tetracycline and erythromycin. The study also employed a totally automated quantitative method based on on-line SPE and liquid chromatography coupled to quadrupole linear ion trap tandem mass spectrometry (LC-QqLIT-MS/MS) for the analysis of these contaminants in vinasse. The application of the aforementioned sample preparation techniques led to the successful extraction of the analytes, and a comparative analysis of the techniques showed that the on-line SPE technique was the most advantageous among the techniques investigated. The quantitative analytical method applied yielded well-defined chromatographic peaks, working range of 1.0–370.0 ng·mL−1, apparent recovery ranging from 80 to 110% for most compounds, repeatability between 3 and 16%, and limits of detection ranging from1.0 to 10 ng·mL−1. The analysis of six vinasse samples from different ethanol producing plants led to the detection of monensin at the concentration of 14.3 ng·mL−1 in their compositions. The results obtained show that fertigation with vinasse is a source of antibiotic contamination in the environment.

Discovery of Quality Markers of Nucleobases, Nucleosides, Nucleotides and Amino Acids for Chrysanthemi Flos From Different Geographical Origins Using UPLC-MS/MS Combined With Multivariate Statistical Analysis.

Nucleobases, nucleosides, nucleotides and amino acids, as crucial nutrient compositions, play essential roles in determining the flavor, function and quality of Chrysanthemi Flos. The quality of Chrysanthemi Flos from different geographical origins is uneven, but there have been no reports about the screening of their quality markers based on nutritional ingredients. Here, we developed a comprehensive strategy integrating ultra performance liquid chromatography coupled with triple-quadrupole linear ion-trap tandem mass spectrometry (UPLC–MS/MS) and multivariate statistical analysis to explore quality markers of Chrysanthemi Flos from different geographical origins and conduct quality evaluation and discrimination of them. Firstly, a fast, sensitive, and reliable UPLC–MS/MS method was established for simultaneous quantification 28 nucleobases, nucleosides, nucleotides and amino acids of Chrysanthemi Flos from nine different regions in China. The results demonstrated that Chrysanthemi Flos from nine different cultivation regions were rich in the above 28 nutritional contents and their contents were obvious different; however, correlation analysis showed that altitude was not the main factor for these differences, which required further investigation. Subsequently, eight crucial quality markers for nine different geographical origins of Chrysanthemi Flos, namely, 2′-deoxyadenosine, guanosine, adenosine 3′,5′-cyclic phosphate (cAMP), guanosine 3′,5′-cyclic monophosphate (cGMP), arginine, proline, glutamate and tryptophan, were screened for the first time using partial least squares discriminant analysis (PLS-DA) and the plot of variable importance for projection (VIP). Moreover, a hierarchical clustering analysis heat map was employed to intuitively clarify the distribution of eight quality markers in the nine different regions of Chrysanthemi Flos. Finally, based on the contents of selected eight quality markers, support vector machines (SVM) model was established to predict the geographical origins of Chrysanthemi Flos, which yielded excellent prediction performance with an average prediction accuracy of 100%. Taken together, the proposed strategy was suitable to discover the quality markers of Chrysanthemi Flos and could be used to discriminate its geographical origin.

Reactivity of para-benzynes in solution and in the gas phase

To rationally design less cytotoxic synthetic drugs based on biologically active para-benzyne intermediates, it is essential to obtain a better understanding on the reactivity of para-benzynes. However, little is still known about their fundamental chemical properties, which requires examination of pure species in simple solvents instead of biological matrices. While fundamental solution studies are limited, the solvent-free reactivity of protonated para-benzynes has been examined previously in the gas phase by using mass spectrometry. In order to facilitate the comparison of results obtained in the gas phase and in solution, we attempted to compare the reactivity of a neutral para-benzyne analog toward dimethyldisulfide in solution to that of its protonated form in the gas phase. The neutral para-benzyne analog, 5,8-didehydroquinoline, was successfully generated via photolysis of an enediyne precursor in dimethyldisulfide/methanol solution and the reaction products were analyzed using a dual linear quadrupole ion trap tandem mass spectrometrometer. However, examination of of the reactions of the same para-benzyne in its protonated form in the gas phase in the mass spectrometer proved to be challenging. Therefore, an analogous, isomeric para-benzyne cation, the 5,8-didehydroisoquinolinium cation, was instead generated in the gas phase from the 5-iodo-8-nitroisoquinoline precursor and its reactions with dimethyldisulfide were examined. This protonated para-benzyne reacted with dimethyl disulfide in the gas phase in the same manner as its neutral isomer in solution; both predominantly abstracted a thiomethyl group by each of the two radical sites. The structures of these products were verified by tandem mass spectrometry experiments based on collision-activated dissociation and using an authentic model compound. These findings suggest that the reactivity of the studied para-benzynes toward dimethyldisulfide is similar in spite of their different protonation states and the different phases in which the reactions were carried out.

An integrated strategy of MS-network-based offline 2DLC-QTOF-MS/MS coupled with UHPLC-QTRAP®-MS/MS for the characterization and quantification of the non-polysaccharides in Sijunzi decoction.

Sijunzi decoction (SJZD), a classic recipe in traditional Chinese medicine (TCM), has been applied for the clinical treatment of gastrointestinal diseases. While there are reports on pharmaceutical substances of SJZD focusing on its polysaccharides, the composition of non-polysaccharides (NPSs) has not yet been holistically clarified. In the current study, offline two-dimensional liquid chromatography coupled with quadrupole time-of-flight tandem mass spectrometry (2DLC-QTOF-MS/MS) was used for comprehensive NPS chemical profiling of SJZD. In addition, the MS-network of SJZD was proposed, which led to the construction of a larger in-house chemical library and accelerated qualitative processing. Four hundred forty-nine components, among which 6 were potentially novel, and 32 were confirmed by standard substances, were identified or tentatively assigned. Furthermore, based on good method validation, 19 representative components were simultaneously quantified by ultra-high-performance liquid chromatography coupled with triple-quadrupole linear ion-trap tandem mass spectrometry (UHPLC-QTRAP®-MS/MS). They were selected for quantification on the account of their bioactive reports on in vivo or in vitro activities, the peak intensity in the mass spectrum, and characteristic structures, which have the potential to be qualitative or quantitative markers of SJZD. The present work furthers understanding of the pharmacological effects and action mechanism of NPSs in SJZD, and provides a useful analytical approach for complex composition research of TCMs.Graphical abstract Supplementary InformationThe online version contains supplementary material available at 10.1007/s00216-021-03302-x.

Comprehensive Identification of Glycosphingolipids in Human Plasma Using Hydrophilic Interaction Liquid Chromatography-Electrospray Ionization Mass Spectrometry.

Glycosphingolipids (GSL) represent a highly heterogeneous class of lipids with many cellular functions, implicated in a wide spectrum of human diseases. Their isolation, detection, and comprehensive structural analysis is a challenging task due to the structural diversity of GSL molecules. In this work, GSL subclasses are isolated from human plasma using an optimized monophasic ethanol–water solvent system capable to recover a broad range of GSL species. Obtained deproteinized plasma is subsequently purified and concentrated by C18-based solid-phase extraction (SPE). The hydrophilic interaction liquid chromatography coupled to electrospray ionization linear ion trap tandem mass spectrometry (HILIC-ESI-LIT-MS/MS) is used for GSL analysis in the human plasma extract. Our results provide an in-depth profiling and structural characterization of glycosphingolipid and some phospholipid subclasses identified in the human plasma based on their retention times and the interpretation of tandem mass spectra. The structural composition of particular lipid species is readily characterized based on the detailed interpretation of mass spectrometry (MS) and tandem mass spectrometry (MS/MS) spectra and further confirmed by specific fragmentation behavior following predictable patterns, which yields to the unambiguous identification of 154 GSL species within 7 lipid subclasses and 77 phospholipids representing the highest number of GSL species ever reported in the human plasma. The developed HILIC-ESI-MS/MS method can be used for further clinical and biological research of GSL in the human blood or other biological samples.

HILIC-UHPLC-QTRAP®/MS2 quantification of 15 neurotransmitters of the combination of donepezil and ginkgo ketoester tablet in different biological matrices from dementia mice: Application to study the synergistic effect of the two drugs

Neurotransmitters (NTs) were signaling molecules which played a key role in the communication of nerve cells. Simultaneous monitoring of NTs possessed important scientific significance for dementia related pharmacology, pathology and drug study. This study developed an effective method for analysis of 15 underivatized NTs on hydrophilic interaction ultra-performance liquid chromatography coupled with triple-quadrupole linear ion-trap tandem mass spectrometry (HILIC-UHPLC-QTRAP®/MS2). Under the optimized chromatographic conditions, good separation of 15 NTs was achieved within 5.0 min. The developed HILIC-UHPLC-QTRAP®/MS2 was validated by matrix effects, linearity, limits of detections and quantifications, precision, stability and recovery. Finally, the validated analytical method was applied to quantify 15 NTs in brain, plasma, intestinal and intestinal contents from normal, dementia model and the combination of ginkgo ketoester tablet (GT) and donepezil drug-administered mice. The result showed that some NTs such as γ-aminobutyric acid, acetylcholine and glutamic acid presented significant differences in the same biological matrix with different doses of the combination of GT and donepezil. In addition, based on the theory of “brain-gut-microbiome” axis, the combination of GT and donepezil with one time of clinical equivalent dose exhibited a synergistic anti-dementia effect by regulating the disordered NTs to normal levels in different biological matrices. In summary, the presented HILIC-UHPLC-QTRAP®/MS2 method might be used to monitor NTs from different clinical biological fluids in the further study.

Determination of bioactive compounds of Artemisia Spp. plant extracts by LC–MS/MS technique and their in-vitro anti-adipogenic activity screening

Ultra Performance Liquid Chromatography coupled with hybrid triple quadrupole linear ion trap tandem mass spectrometry (UPLC-ESI-QqQLIT-MS/MS) method in multiple reaction monitoring (MRM) acquisition mode was developed and validated for identification and simultaneous determination of potential anti-diabetic and anti-malarial compounds in ethanolic extracts of different Artemisia species. The chromatographic separation was carried out on an Acquity BEH™ C18 column (1.7 μm, 2.1 × 50 mm) with 0.1 % (v/v) formic acid in water and acetonitrile as mobile phase under gradient condition in 6 min. The developed method was validated in terms of linearity, LOD, LOQ, precision, stability and recovery according to international conference on harmonization guidelines. The correlation coefficients of all the calibration curves were ≥0.9902 and recoveries ranged from 98.22 to 104.49% (RSD ≤2.18 %). Relative standard deviations of intra-day, inter-day precisions and stability were ≤ 1.04, 1.09 and 2.80 %, respectively. The quantitative results showed remarkable differences in the content of all the compounds in different Artemisia species. The quantitative values of each peak were summarized as mean ± SD. The statistical analysis for comparison of observed quantitative differences of each compound was done to show that they are statistically significant. In-vitro assessment of extracts of selected Artemisia species inhibited adipocyte differentiation in 3T3-L1 cells, hence it may have certain phytochemicals which are responsible for reducing obesity and related metabolic disorders.

In vivo and in silico characterization of apocynin in reducing organ oxidative stress: A pharmacokinetic and pharmacodynamic study.

Apocynin has been widely used in vivo as a Nox2‐contaninig nicotinamide adenine dinucleotide phosphate oxidase inhibitor. However, its time‐dependent tissue distribution and inhibition on organ reactive oxygen species (ROS) production remained unclear. In this study, we examined apocynin pharmacokinetics and pharmacodynamics (PKPD) after intravenous (iv) injection (bolus, 5 mg/kg) of mice (CD1, 12‐week). Apocynin was detected using a HPLC coupled to a linear ion‐trap tandem mass spectrometer. Apocynin peak concentrations were detected in plasma at 1 minute (5494 ± 400 ng/mL) (t 1/2 = 0.05 hours, clearance = 7.76 L/h/kg), in urine at 15 minutes (14 942 ± 5977 ng/mL), in liver at 5 minutes (2853 ± 35 ng/g), in heart at 5 minutes (3161 ± 309 ng/g) and in brain at 1 minute (4603 ± 208 ng/g) after iv injection. These were accompanied with reduction of ROS production in the liver, heart and brain homogenates. Diapocynin was not detected in these samples. Therapeutic effect of apocynin was examined using a mouse model (C57BL/6J) of high‐fat diet (HFD, 16 weeks)‐induced obesity and accelerated aging. Apocynin (5 mmol/L) was supplied in drinking water during the HFD period and was detected at the end of treatment in the brain (5369 ± 1612 ng/g), liver (4818 ± 1340 ng/g) and heart (1795 ± 1487 ng/g) along with significant reductions of ROS production in these organs. In conclusion, apocynin PKPD is characterized by a short half‐life, rapid clearance, good distribution and inhibition of ROS production in major organs. Diapocynin is not a metabolite of apocynin in vivo. Apocynin crosses easily the blood‐brain barrier and reduces brain oxidative stress associated with metabolic disorders and aging.

Analysis and evaluation of nucleosides, nucleobases, and amino acids in safflower from different regions based on ultra high performance liquid chromatography coupled with triple-quadrupole linear ion-trap tandem mass spectrometry.

Safflower has both medicinal and edible values but research on its nutrient composition is still lacking. This study was established for the quantitative determination of 28 nucleosides, nucleobases, and amino acids based on the ultra-performance liquid chromatography coupled with triple-quadrupole linear ion-trap tandem mass spectrometry. Analysis of 30 batches of safflower from different producing areas indicated that the contents of l-proline, l-asparagine, l(+)-arginine, l-serine, l-histidine, uracil, guanosine, and uridine was high in safflower. Principle component analysis and cluster analysis found that samples from different regions could be distinguished well, and samples from the same area could be clustered into one class, different geographical environments may cause the differences of nucleosides, nucleobases, and amino acids in safflower. The analysis of principal component analysis, cluster analysis, and counter propagation artificial neural network show similar results. Then the content of nucleosides, nucleobases, and essential amino acids were compared, and found that the content in safflower from Gansu was higher than those from other regions, and there was a little difference between the samples from Xinjiang, Sichuan, and Yunnan. This research revealed the composition of nucleosides, nucleobases, and amino acids in safflower, and provided a theoretical basis for utilization of safflower.

Identification and quantification of phospholipids in strawberry seeds and pulp (Fragaria × ananassa cv San Andreas) by liquid chromatography with electrospray ionization and tandem mass spectrometry.

An extensive characterization and quantification of intact phospholipids (PLs) in strawberry (Fragaria × ananassa cv San Andreas) seed and pulp was carried out by hydrophilic interaction liquid chromatography (HILIC) and electrospray ionization (ESI) coupled to either Fourier-transform (FT) orbital-trap or linear ion-trap tandem mass spectrometry (LIT-MS/MS). More than 150 intact polar lipids including phosphatidylcholines (PCs), phosphatidylethanolamines (PEs), phosphatidylglycerols (PGs), phosphatidic acids (PAs), phosphatidylinositols (PIs), lysophosphatidylcholines (LPCs), and lysophosphatidylethanolamines (LPEs) were identified in negative ESI mode. PC 18:2/18:2 and 18:2/18:3 were found to be the major components of strawberry lipid extracts at concentrations of 230 ± 36 and 189 ± 32 μg/g, respectively, in seeds and at concentrations of 330 ± 50 and 140 ± 22 μg/g, respectively, in pulp. The lipidic extracts of both strawberry seeds and pulp exhibited the dominance of LPC 16:0/0:0 at a content of 132 ± 19 and 114 ± 16 μg/g, respectively, and LPC 0:0/18:2 at 236 ± 20 and 150 ± 20 μg/g, respectively. The other most abundant species of strawberry seeds and pulp were PE 18:2/18:2, 40 ± 9 and 190 ± 40 μg/g, followed by PI 16:0/18:2, 51 ± 15 and 24 ± 8 μg/g, respectively, while PG, PA, and LPE show comparable abundance below 10 μg/g. The most recurrent fatty acyl substituents of PLs were C18:3 (α-linolenic acid), C18:2 (linoleic acid), C18:1 (oleic acid), C18:0 (stearic acid), C16:0 (palmitic acid), and relatively high contents of a shorter chain such as C14:0 (myristic acid).

Evaluation of selected pharmaceuticals and personal care products in water matrix using ion trap mass spectrometry: A simple weighted calibration curve approach

A novel analytical method is presented for 12 target pharmaceutical and personal care products (PPCPs), belonging to different classes like antibiotics, non-steroid anti-inflammatory drugs, parabens, UV-filters, plasticizer, and antibacterials. The method development comprises of solid-phase extraction (SPE) with lipophilic–hydrophilic material balanced Oasis HLB cartridge, followed by reverse-phase liquid chromatography interfaced to linear ion trap tandem mass spectrometry (LC–MS/MS) with electrospray ionization. Chromatographic separation was achieved with a gradient elution of 25 min run time using 5 mM ammonium acetate buffer with pH adjustment using acetic acid. In addition, cost effective organic solvent with buffer used together as the mobile phase with Chromatopak C18 column (150 mm × 4 mm, 5-μm,) in negative ionization mode. Recoveries ranged from 61.74 % to 119.89 % for most of the compounds. Matrix-matched calibration curves were used for counterbalancing the matrix effects for all the analytes, and ibuprofen D3 internal standard was used for assessing the effectiveness of extraction technique and monitoring the recovery of sample analysis. Simple empirical weighted linear regression curve technique was adopted practically for each analysis in enhancing the analyte accuracy at lower quantification level. The 1/x2 model was selected as the best suitable model for quantification of analytes, which can be evaluated by deviation from back-calculated concentration in terms of percentage relative error (%RE). Weighted calibration curves with regression value for most of the compounds were ≥ 0.98, except triclosan with a regression value ≥ 0.93. Precision showed as % relative standard deviation (%RSD) were always below 15.0 %. Accuracy-test was evaluated by the statistical one-sample t-test and no significant difference was observed between nominal and experimental value. The limit of quantification (LOQ) ranged from 3.0 ng/mL (BP1) to 1000 ng/mL (naproxen). Finally, the validated method was used for the first time to determine target analytes in surface water samples collected from Arkavathi river flowing across southern India’s Bengaluru city.