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Background Dicamba is widely used in agricultural production in China, but it is extremely soluble in water and can be harmful to human health when it enters the body via water drinking. It is necessary to establish an accurate, sensitive, and rapid detection method to determine the residues of dicamba in domestic drinking water. Objective To establish two methods for the determination of dicamba residues in drinking water by high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) and gas chromatography-tandem mass spectrometry (GC-MS/MS) respectively. Methods The conditions of the proposed method using HPLC-MS/MS included CAPCELL PAK ST chromatographic column, ammonium formate water solution and methanol as the mobile phase, and isocratic elution. The system was operated under multiple reaction monitoring mode and electrospray negative ionization mode. Trimethylsilylated diazomethane was used as a derivatizing agent for GC-MS/MS, and an external standard curve was used to evaluate the system. The residues of dicamba in seven water samples of tap water or secondary water supply from six regions in Chengdu were detected by the established systems to evaluate their applicability and to understand the status quo of dicamba residues in drinking water. Results For the HPLC-MS/MS, the linear range of dicamba was 1.00-100 μg·L−1, the regression equation was \begin{document}$\hat Y $\end{document}=1250.9X+2681.5, the correlation coefficient was 0.9988, the relative standard deviations were 1.23%-26.3%, the limit of detection was 0.95 μg·L−1, and the spiked recoveries were 91.8%-111%. For the GC-MS/MS, the linear range of dicamba was 0.200-10.0 μg·L−1, the regression equation was \begin{document}$\hat Y $\end{document}=190597X+40911, the correlation coefficient was 0.9993, the relative standard deviations were 0.64%-3.90%, the limit of detection was 0.18 μg·L−1, and the spiked recoveries were 97.3%-105%. No dicamba residue was identified in the seven water samples of tap water or secondary water supply from six regions in Chengdu by the proposed methods. Conclusion The two detection methods established in this study are sensitive and rapid, meet the requirements from the detection of dicamba residues in drinking water, and provide an experimental basis for subsequent research on the detection of dicamba residues. In the future, it is necessary to continue to pay attention to the pollution of dicamba in drinking water in Chengdu.
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Objective:High performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) was used to quantify the levels of vitamins A, D and E in pregnant women during the second trimester, and to investigate the change trends of serum vitamins A, D and E levels during pregnancy.Method:A total of 720 pregnant women with an average age of (29.7±4.4) years and 12-22 weeks of gestation were included from October 1, 2021 to October 30, 2022 in the obstetrics department of the People′s Hospital of Wuhan University. The concentrations of vitamins A, D and E were determined by HPLC-MS/MS. The concentration levels of each group were statistically analyzed and the deficiency rate were calculated.Results:The distribution range of vitamin A, D and E (95% CI) was 0.74-2.74 μmol/L, 2.88-25.37 ng/ml and 6.18-35.08 μmol/L, with the deficiency rates were 9.30%, 93.76% and 35.83%, respectively. Vitamin A, D and E levels in the twin group were (1.67±0.51) μmol/L, (13.18±7.44) ng/ml and 11.97 (8.85, 14.60) μmol/L, respectively. They were significantly higher than those in the singlet group (1.45±0.36) μmol/L, (10.87±5.26) ng/ml and 10.46 (6.99, 14.11) μmol/L, with statistical significance by independent sample t-test ( P<0.001). The concentration of vitamin D in the lower BMI group (<22 kg/m 2) was (12.54±5.74) ng/ml, significantly higher than that in the fat group (≥22 kg/m 2) (10.46±4.90) ng/ml, and the rank-sum test was statistically significant ( P<0.001). Conclusion:In this study, the levels of three vitamins were monitored in mid-pregnancy using HPLC-MS/MS, and the changes of serum vitamin A, D, and E levels during pregnancy were analyzed.
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Objective@#To establish a ultra-high performance liquid chromatography-tandem triple quadrupole mass spectrometry method for rapid simultaneous determination of quinclorac, acetochlor, butachlor and metolachlor in urine.@*Methods@#Urine samples were diluted 10 times, prepared into the mixed standard solution, and subjected to gradient elution on the ACQUITY UPLC BEH C18 column (100 mm×2.1 mm, 1.7 μm) with 0.1% formic acid and acetonitrile as the mobile phase. The quinclorac, acetochlor, metolachlor and butachlor levels were determined using electrospray ionization-positive ultra-high performance liquid chromatography-tandem triple quadrupole mass spectrometry with the multiple reaction monitoring mode.@*Results@#Four herbicides were effectively separated on the ACQUITY UPLC BEH C18 column (100 mm× 2.1 mm, 1.7 μm), and good linear relationships were observed for quinclorac, acetochlor and butachlor at 1 to 25 μg/L and for metolachlor at 0.2 to 25 μg/L, with all linear correlation coefficients of >0.999. The detection limts of quinclorac, acetochlor, butachlor and metolachlor were 0.10, 0.10, 0.20 and 0.01 μg/L, respectively. The recovery rates of quinclorac, acetochlor and butachlor were 107.42%, 93.94% and 90.27% from urine samples at a spiked level of 5 µg/L, with relative standard deviations of 4.82%, 3.84% and 6.76%, and the recovery rate of metolachlor was 89.51% at a spiked level of 0.5 µg/L, with a relative standard deviation of 8.98%.@*Conclusion@#The chromatography and mass spectrometry conditions are optimized in this ultra-high performance liquid chromatography-tandem mass spectrometry, which is effective for rapid simultaneous determination of quinclorac, acetochlor, metolachlor and butachlor in urine samples.
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ObjectiveA method was developed for the rapid determination of 18 common disinfection by-products including halogenated oxides and haloacetic acid （HAAs） in drinking water by high performance liquid chromatography tandem mass spectrometry （HPLC-MS/MS）. MethodThe water sample was filtered by 0.22 μm hydrophilic membrane then the analytes were separated on a PFP （2.1 mm× 100 mm， 2.7 μm） pentafluorophenyl column with 0.1% acetic acid and acetonitrile as mobile phase gradient elution. Ionization in anionic electrospray mode was detected by multi-reaction monitoring （MRM） mode. The external standard method was used for quantitation. ResultsThe correlation coefficients of 18 disinfection by-products were above 0.999 in the corresponding linear range. The average spiked recoveries of 1， 10 and20 times of LOQ of each analyte were 91.6%‒101.8%， and the relative standard deviation （RSD） was 1.2%‒6.4%. The LOD and LOQ were 0.020‒2 μg·L-1 and 0.050‒5 μg·L-1， respectively. ConclusionThis method is simple， sensitive and accurate， and could be used for the routine analysis of 18 common disinfection by-products in drinking water.
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OBJECTIVE To establish a method for simultaneous determination of 15 bile acids in Tongren niuhuang qingxin pills， and to determine the contents of 15 batches of samples. METHODS Using dehydrocholic acid as internal standard， the determination was performed by ultra-high performance liquid chromatography-tandem mass spectrometry （UPLC-MS/MS） method. The determination was performed on Hypersil GOLD C18 column with methanol-0.1% formic acid solution as the mobile phase by gradient elution at the flow rate of 0.2 mL/min. The column temperature was 40 ℃ ， and the sample size was 2 µL. Using heated electrospray ion source， parallel reaction monitoring mode scanning was performed in negative ion mode. SPSS 24.0 software was used for chemical pattern recognition analysis of content determination results. RESULTS The 15 bile acid components had a good linear relationship with peak area （all R2≥0.998 9）； their precision， repeatability and stability were all good （all RSD≤5.49%）； the average recoveries were 93.8%-105.7% （RSD was 0.5%-5.8%）. The average contents of taurocholic acid， 7-oxodeoxycholic acid， 12-dehydrocholic acid， glycocholic acid， 3-oxo-7α， 12α-hydroxy-5β-cholanoic acid， taurochenodeoxycholic acid， 3α-hydroxy- 7-oxo-5β -cholanic acid， hyocholic acid， taurodeoxycholic acid sodium salt hydrate， hyodeoxycholic acid， cholic acid， glycochenodeoxycholic acid， glycodeoxycholic acid， chenodeoxycholic acid and deoxycholic acid were 670.56， 25.97， 10.54， 280.12， 4.04， 29.81， 182.98， 813.55， 120.95， 220.31， 797.37， 18.37， 68.59， 30.13， 59.82 μg/g， respectively. Both cluster analysis and principal component analysis divided 15 batches of Tongren niuhuang qingxin pills into 2 categories， S1-S12 as one category and S13-S15 as the other category. CONCLUSIONS The established method is accurate， sensitive and specific， and can determine many types of bile acids. It also can quickly achieve the quantitative analysis of 15 bile acids in Tongren niuhuang qingxin pills， which is suitable for the quality control of this drug.
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OBJECTIVES@#To establish a combined high performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) and gas chromatography-mass spectrometry (GC-MS) method to detect the synthetic cannabinoid CUMYL-PEGACLONE in e-cigarette oil and hair.@*METHODS@#HPLC-MS/MS and GC-MS were used to establish the detection method of CUMYL-PEGACLONE, and the hair of drug-involved persons and the seized e-cigarette oil were detected.@*RESULTS@#The main mass spectrometry characteristic ions m/z of CUMYL-PEGACLONE measured by GC-MS were 91, 179, 197, 254 and 372. CUMYL-PEGACLONE had a good linear relationship in the mass concentration range of 2-50 ng/mL, and the linear correlation coefficient (r) was greater than 0.99. The limit of detection (LOD) of CUMYL-PEGACLONE in hair was 0.01 ng/mg, and the limit of quantitation (LOQ) was 0.02 ng/mg. The LOD of CUMYL-PEGACLONE in e-cigarette oil was 1 ng/mg, and the LOQ was 2 ng/mg. The average recoveries of CUMYL-PEGACLONE under the attempt at high, intermediate and low levels in blank human hair and e-cigarette oil matrix were 98.2%-132.4% and 93.5%-110.6%, and the intraday and intraday precision were 1.2%-12.9% and 0.7%-2.9%. CUMYL-PEGACLONE was detected in the hair of 15 drug-involved persons. Except for 1 person who was lower than LOQ, the concentration of CUMYL-PEGACLONE in the hair of other 14 persons was 0.035-0.563 ng/mg. The mass fraction of CUMYL-PEGACLONE in 2 e-cigarette oil were 0.17% and 0.21%, respectively.@*CONCLUSIONS@#The established HPLC-MS/MS and GC-MS methods are applied to the detection of HPLC-MS/MS in drug-related cases, which provides strong evidence support for the handling authority to quickly investigate these cases, and also provides a reference for the identification of such substances in future.
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Humans , Illicit Drugs/analysis , Tandem Mass Spectrometry , Electronic Nicotine Delivery Systems , Cannabinoids , Hair/chemistry , Limit of Detection , Substance Abuse Detection/methodsABSTRACT
OBJECTIVES@#To analyze the characteristics of diphenidol poisoning cases and to provide clues and technical means for the identification of such cases.@*METHODS@#Biological samples of 9 deaths caused by diphenidol poisoning were detected by ultra-high performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS), and the characteristics of these cases were analyzed retrospectively.@*RESULTS@#Most of the deaths caused by diphenidol poisoning were young females. The dosage was between 60 and 300 tablets, and the mass concentration of diphenidol in the postmortem blood ranged from 0.87 to 99.00 μg/mL. There was no correlation between the dosage and the concentration of diphenidol in the blood.@*CONCLUSIONS@#Diphenidol poisoning has the characteristics of high concealment and lethality. More attention should be paid to suicide cases, and diphenidol should be recommended as a routine detection item to avoid missing detection.
Subject(s)
Female , Humans , Chromatography, Liquid/methods , Tandem Mass Spectrometry/methods , Retrospective Studies , Administration, OralABSTRACT
Endogenous ribonucleotides(RNs)and deoxyribonucleotides(dRNs)are important metabolites related to the pathogenesis of many diseases.In light of their physiological and pathological significances,a novel and sensitive pre-column derivatization method with N-(t-butyldimethylsilyl)-N-methyltri-fluoroacetamide(MTBSTFA)was developed to determine RNs and dRNs in human cells using high-performance liquid chromatography tandem mass spectrometry(HPLC-MS/MS).A one-step extraction of cells with 85％methanol followed by a simple derivatization reaction within 5 min at room temper-ature contributed to shortened analysis time.The derivatives of 22 nucleoside mono-,di-and tri-phosphates were retained on the typical Cig column and eluted by ammonium acetate and acetonitrile in 9 min.Under these optimal conditions,good linearity was achieved in the tested calibration ranges.The lower limit of quantitation(LLOQ)was determined to be 0.1-0.4 μM for the tested RNs and 0.001-0.1 μM for dRNs.In addition,the precision(CV)was＜15％and the RSD of stability was lower than 10.4％.Furthermore,this method was applied to quantify the endogenous nucleotides in human colorectal carcinoma cell lines HCT116 exposed to 10-hydroxycamptothecin.In conclusion,our method has proven to be simple,rapid,sensitive,and reliable.It may be used for specific expanded studies on intracellular pharmacology in vitro.
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@#An innovative approach to quantitatively analyze the histamine and its precursor histidine simultaneously in biological matrices was established for the first time based on double adsorption combined with high performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS).The internal standard was 2-dihydroxybenzoic acid (DHB).The plasma and brain tissue homogenate was protein precipitated with 3-fold acetonitrile, and the supernatant was then sampled for injection analysis.The chromatographic separation of the target components was achieved on an amino chromatography column (ODS-SPXBridge? Amide).Gradient elution was carried out with the mobile phase consisting of solvent A (0.1% formic acid and 1mmol/L ammonium formate in water) and solvent B (acetonitrile).Mass spectrometry was employed for quantitative analysis with ESI ion source in multiple reaction monitoring (MRM) mode.In order to improve the specificity and accuracy, activated carbon and calcite were used for the double adsorption of biological matrices for the first time.The adsorbed matrix was then used for methodology validation.The results showed that histamine and histidine were linear in the quantitative range (correlation coefficient r ≥ 0.999).Accuracy, precision, extraction recovery, matrix effect and stability all met the requirements of biological sample analysis.All results suggested that the present method could not only be efficiently and reliably used for simultaneous quantitative analysis of histamine and histidine in biological samples, but also provide reference for the detection of other endogenous substances.
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Objective: To establish a method for rapid determination of bongkrekic acid (BA) in plasma by high performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS). Methods: In November 2020, plasma samples were extracted by methanol and acetonitrile (1∶1) and purified directly. The samples were separated by C18 column. Gradient elution was carried out with 5 mmol/L ammonium acetate water acetonitrile solution as mobile phase. Under the optimized instrument conditions, the electrospray ionization multiple reaction monitoring (MRM) mode was used, and the external standard method was used for quantitative analysis. Results: The linear relationship of BA in plasma was good in the concentration range of 2-100 μg/L, the correlation coefficient was 0.9998, the average recovery was 83.7%-112.0%, the relative standard deviation within and between batches was less than 10%, the detection limit of the method was 0.7 μg/L and the lower limit of quantification was 2.0 μg/L. Conclusion: The method is simple, rapid, accurate and sensitive, and can meet the requirements for the determination of BA in blood samples of poisoning patients.
Subject(s)
Humans , Bongkrekic Acid , Chromatography, High Pressure Liquid , Solid Phase Extraction , Tandem Mass SpectrometryABSTRACT
Objective To establish a detection system of ultra high performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) for everolimus concentration in whole blood of liver transplant recipients. Methods The proteins of samples were precipitated with methanol and zinc sulfate, and everolimus-D4 was used as the internal standard. Phenomenex Kinetex PFP column was used. The mobile phase A was water (containing 2 mmol/Lammonium formate and 0.1% formic acid), and the mobile phase B was methanol (containing 2 mmol/L ammonium formate and 0.1% formic acid). The gradient elution was performed with the flow rate of 1 mL/min, the column temperature of 50 ℃ and the injection volume of 1 μL. The multi-reaction monitoring mode was used to quantitatively analyze with electrospray positive ionization. The UPLC-MS/MS detection system required only 100 μL of whole blood, and could achieve a sufficient lower limit of quantification without complicated sample preparation. The total running time was within 4.5 min. Linear regression (1/x2) analysis was performed using peak area of everolimus / peak area of everolimus-D4 (y) and concentration of everolimus/concentration of everolimus-D4 (x) to calculate the calibration function and analyze its accuracy and linear relationship. UPLC-MS/MS was used to detect the trough blood concentration of everolimus in blood samples of 5 recipients after liver transplantation. Results The accuracy of quality control was within 15%, and the linear relationship of everolimus was good in the blood concentration range of 1-100 ng /mL(R2 > 0.990). Trough blood concentration of everolimus measured in blood samples of 5 liver transplant recipients ranged from 3.77 to 9.27 ng/mL. Conclusions The detection system of UPLC-MS/MS in this study is suitable for monitoring the concentration of everolimus in whole blood of liver transplant recipients because of its high accuracy, simple sample processing method and short detection time.
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Objective To establish a method combining QuEChERS and ultra-high liquid chromatography-tandem mass spectrometry （UPLC-MS/MS） for rapid screening and testing of three types of new psychoactive tryptamines in human blood： 5-MeO-DALT, 5-MeO-MiPT and 5-MeO-DiPT. Methods The effects of the type of extractant, the type and dosage of salting-out agent, and the dosage of adsorbent on the test results of the three tryptamines were investigated. Blood samples were processed by QuEChERS method and then determined by UPLC-MS/MS. Results The linear relationships of 5-MeO-DALT, 5-MeO-MiPT and 5-MeO-DiPT in human blood were good in the range of 0.5-100, 0.5-100 and 0.2-100 ng/mL, respectively, with their coefficients higher than 0.99. The limits of detection （LODs） were 0.1-0.2 ng/mg. The recoveries ranged from 84.86% to 94.57%. Intra-day and inter-day precisions were good. Conclusion The method is simple, rapid, easy to operate and has a high recovery. It is suitable for the qualitative and quantitative study of tryptamines in blood and can provide the reference for public security organs to deal with related cases.
Subject(s)
Humans , Chromatography, High Pressure Liquid , Chromatography, Liquid , Limit of Detection , Tandem Mass Spectrometry , TryptaminesABSTRACT
Objective To develop a method for the simultaneous determination of 15mycotoxins in peanuts by ultra high performance liquid chromatography-tandem mass spectrometry with QuEChERS EMR-Lipid approach and stable isotope dilution. Methods The samples were extracted by 2% formic acid acetonitrile-water (50 : 50, V/V) and then purified with QuEChERS EMR-Lipid approach.The mycotoxins were fully separated on a pentafluorophenyl column under a gradient elution with methonal-0.01%formic acid aqueous solution.The mycotoxins were analyzed by UPLC-MS/MS with multiple reaction monitoring (MRM) mode and quantified by isotope internal standard method. Results Fifteen mycotoxins had good linear relationship in the certain correlation ranges with the correlation coefficients all above 0.995 and the detection limits were 0.1－10 μg/kg.The mean recoveries ranged from 81.2% to 115.3% with RSD (n=6) varying from 2.1% to 10.7%. Conclusion The method is simple, highly sensitive, practical, and proves to be suitable for quantitative analysis of 15 mycotoxins in peanuts.
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Objective: To study on the changes of serum small metabolites in patients with lung cancer and pneumonia, assess the performance of these metabolites on differential diagnosis between lung cancer and pneumonia, and establish diagnostic model. Methods: Liquid chromatography tandem mass spectrometry(LC-MS/MS) was applied to test the serum metabolites, including 13 amino acids and 15 bile acids, of 95 patients with lung cancer, 69 patients with pneumonia and 90 healthy people. T test and Mann-Whitney U test were used to analyze the differences among the three groups. Binary logistic regression was applied to screen valuable indexes and establish diagnostic model. The receiver operating characteristic curve (ROC) was used to compare the differential diagnostic value of single index and diagnostic model. Results: Compared with the control group, 3 kinds of amino acids and 7 kinds of bile acids were decreased significantly, while 1 kind of amino acid and 2 kinds of bile acids were increased significantly in pneumonia patients. 6 kinds of amino acids and 2 kinds of bile acids were decreased significantly, while 2 kinds of amino acids and 4 kinds of bile acids were increased significantly in lung cancer patients. Deoxycholic acid was the most valuable metabolite in differential diagnosis. Citrulline, phenylalanine and deoxycholic acid were screened to establish differential diagnostic model of lung cancer and pneumonia. The area under curve (AUC) of the model was 0.829, and the Cut-Off value was 0.55, while the sensitivity was 76.8%, the specificity was 79.7%, and the coincidence rate was 78.3%. Conclusion: This study revealed that some small metabolites in serum of the patients with pneumonia and lung cancer have changed significantly. The diagnostic model composed of some metabolites has the potential value to assist differential diagnosis of lung cancer and pneumonia.
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OBJECTIVE@#To study the plasma concentration and pharmacokinetics of 3, 29-Dibenzoyl Karounitriol (3, 29-DK) from sustained- release pellets and extracts of Trichosanthes at different time points in rats using high-performance liquid chromatography- tandem mass spectrometry (LC-MS/MS).@*METHODS@#Healthy male SD rats were given a single gavage of Trichosanthes sustained-release pellets or Trichosanthes extract, and orbital blood samples were taken at different time points within 48 h after drug administration in the pellet group and within 5 h in Trichosanthes extract group for determination of the plasma concentrations of 3, 29-DK using LC-MS/MS. The standard curve of 3, 29-DK content was established, and the specificity, minimum detection limit, precision and accuracy, extraction recovery, stability and matrix effect of LC-MS/MS analysis were assessed. The mean plasms levels of 3, 29-DK at different time points after the drug administration were determined and its pharmacokinetic parameters were calculated using Das 2.0 software.@*RESULTS@#LC-MS/MS analysis showed a good linearity of 3, 29-DK concentration within the range of 0.5-32 ng/mL, and the results of methodological validation confirmed the validity of this method for biological sample determination. Trichosanthes sustained-release pellets and Trichosanthes extract showed significant differences in their AUC, AUC, MRT, MRT, t and T of 3, 29-DK after administration in rats ( < 0.05).@*CONCLUSIONS@#Trichosanthes sustained-release pellets are capable of sustained-release of 3, 29-DK in rats, and thus provides a basis for the study of new dosage forms of Trichosanthes.
Subject(s)
Animals , Male , Rats , Chromatography, High Pressure Liquid , Delayed-Action Preparations , Rats, Sprague-Dawley , Reproducibility of Results , Tandem Mass Spectrometry , TrichosanthesABSTRACT
Objective::To investigate the effect of polyethylene glycol 400 (PEG400) on rat bile excretion of baicalin and its main metabolite [baicalein 6-O-β-D-glucuronide (B6G)], and to analyze its mechanism of action. Method::Rats were randomly divided into baicalin+ water group and baicalin+ PEG400 group, the anesthesia was induced by intraperitoneal injection of 10% chloral hydrate (dose of 4 mL·kg-1) to prepare a rat bile duct intubation model. After the rats were fully awake, rats were given baicalin aqueous solution and baicalin PEG400 solution with dose of 168 mg·kg-1 for baicalin, respectively. And bile was collected from 0 h to 12 h after administration. UPLC-MS/MS was used to determine the concentration of drug excreted through bile at different time periods. Thermo Hypersil GOLD C18 column was used with acetonitrile (A)-0.1% formic acid solution (B) as the mobile phase for gradient elution (0-9 min, 90%-27%B; 9-10 min, 27%-90%B; 10-12 min, 90%B), the flow rate was 0.3 mL·min-1, the column temperature was 30 ℃, the injection volume was 5 μL. The mass spectra were obtained in positive ion mode with electrospray ionization (ESI). The effects of PEG400 on the activities and expressions in rat liver of uridine diphosphate glucuronyltransferase (UGT) 1A8 and UGT1A9 were studied in vitro incubation assay and enzyme linked immunosorbent assay (ELISA). Result::Compared with the baicalin+ water group, in the baicalin+ PEG400 group, the bile cumulative excretions of baicalin and B6G increased by 1.8 times and 2.1 times within 12 h, respectively. PEG400 increased the enzyme activities of UGT1A8 and UGT1A9 by 2.0 times and 1.5 times, and their concentrations in liver were increased by 2.2 times and 1.3 times, respectively. Conclusion::PEG400 can significantly increase the bile excretion of baicalin and its main metabolite B6G by enhancing the activities and expressions of UGT1A8 and UGT1A9, and its promoting effect on bile excretion of B6G is greater than that of baicalin, which provides a basis for the rational clinical application of PEG400 and the design of new dosage forms of flavonoids such as baicalin.
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Aim To determine the distribution of succinylcholine chloride (Suc) at toxic dose in rats by establishing UHPLC-MS/MS analysis. Methods The rats were subcutaneously injected with three doses of Suc, and 4 h later, rat serum and major organs were taken for acetonitrile protein precipitation and purified by solid phase extraction with WCX column. Luna NH2 column (2 mm × 100 mm, 3 μm) was used for chromatography. The mobile phase was 0. 1% formic acid-acetonitrile isoelution. Mass spectrometry was carried outwith positive ion scanning multi-reaction monitoring mode (MRM). Qualitative and quantitative analysis was conducted on the ion pairs of Suc (m/z 145. 1→93.3, m/z 145.1→115.4). Results The detection limit of Suc was 0.01 μg · L-1, the recovery rate was 89. 5% ∼ 95. 4%, and the intraday and mtraday RSD was less than 15%. Except in the untreated rat, Suc was detected in the serum, heart, liver, kidney and other major organs from Sue-administered rats, and Suc content in the kidney was the highest among organs. Conclusions Sucat poisoning dose is distributed in the serum, heart, liver, kidney and other tissues. The content in the kidney is the highest; UHPLC-MS/ MS analysis is an effective and reliable method for detecting the drug content in Sue-poisoned rats.
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A QuEChERS-ultra high performance liquid chromatography-tandem mass spectrometry method was developed for qualitative screening of 169 veterinary drug residues in bear bile powder, including β-agonists and inhibitors, antibiotics (penicillins, β-lactams, sulfomamides, quinolones, chloramphenicals, tetracyclines, nitroimidazoles, macrolides, polyethers, etc.), antiviral drugs, anthelminitics, steroid hormones, nonsteroidal antiinflammatory drugs (NSAIDs) and sedatives. The samples were extracted by Na2EDTA-McIlvaine buffer solution and 5% fomic acid-acetonitrile solution, then purified by dispersive solid phase extraction. Detection of veterinary drug residues by ultra high performance liquid chromatography-triple quadrupole mass spectrometry was conducted and qualitative confirmed by ion ratios. The limits of detection of 169 veterinary drugs were 1-1 000 μg·kg-1. The method is simple and fast, which had been used for the analysis of actual samples, and can be extended to the detection of similar matrix.
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Objective • To perform the pharmacokinetic (PK) studies of DDDA3, a dual inhibitor of both acetylcholinesterase and butyrylcholinesterase, in order to provide experimental evidence for the evaluation of in vivo activity against Alzheimer's disease (AD) and the formulation optimization. Methods • A high performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) method for the quantification of DDDA3 was developed and validated. This method was applied to pharmacokinetic studies of DDDA3 in rat plasma. Protein precipitation approach was used to prepare plasma samples. To lower the detection limit, the concentration step was utilized. The samples were analyzed on a Zorbax SB-Aq column (2.1 mm×100 mm, 3.5 μm) with the mobile phase composed of methanol and water (75:25 by volume, containing 0.1% formic acid and 10 mmol/L ammonium formate) and determined by positive electrospray ionization in multiple reaction monitoring mode. Results • The lower limit of quantification was 0.5 ng/mL and the linear range was 0.5-500 ng/mL. The absolute oral bioavailability of DDDA3 in SD rats was 78.4%. Conclusion • DDDA3 has high potentials as anti-AD agents, with good oral bioavailability, fast absorption rate, and long-lasting blood concentration; however, the formulation should be optimized to improve the solubility.
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Objective@#To establish a high performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) method for the detection of serum oleic acid (OA), and preliminarily evaluate the role of OA in insulin resistance (IR) of type 2 diabetes (T2DM). @*Methods@#OA-［ 13 C 5 ］ was used as isotope-labeled internal standard, and the ion pairs of OA and OA-［ 13 C 5 ］ were 281.3/281.3 and 286.3/286.3, respectively. The ultrapure water was used as mobile phase A and methanol: acetonitrile (1∶1, v/v) as mobile phase B in a ZORBAX SB-Aq C18 reversed phase column. Meanwhile, the gradient elution system with a flow rate of 0.3 mL/min was used. According to the CLSI guidelines (EP15-A3), the reliability of the established method was evaluated by detecting the performance indicators such as precision, trueness, linear range, stability and carrying contamination rate. Serum OA levels were detected by the established HPLC-MS/MS method in 109 patients with clinically diagnosed T2DM and 100 healthy controls. The insulin resistance index (HOMA-IR) was calculated to evaluate IR, and the relationship between OA and IR was further analyzed. @*Results@#The established HPLC-MS/MS method for the detection of serum OA had good specificity and linearity in the range of 10-1 000 μmol/L (y=0.007 55x+0.004 83,r=0.997 7), and the low limit of quantification (LLOQ) was 10 μmol/L. It also had good precision, and the within-run coefficient of variation (CV) and total CV were not more than 1.62% and 1.73%, respectively, indicating that the method was suitable for the detection of serum OA. The serum OA levels in T2DM patients ［(425.58 ± 220.17) μmol/L］ were significantly higher than that in the healthy controls ［(113.20±58.00) μmol/L］, and serum OA levels were significantly correlated with HOMA-IR in T2DM patients and healthy controls. The area under the receiver operating characteristic (ROC) curve (AUC) of OA for the diagnosis of IR was 0.689. When the cut-off value identified by Youden index was 235.8 μmol/L, the sensitivity and specificity were 70.4% and 63%, respectively. When OA combined with fasting blood glucose (FBG) to diagnose IR, the AUC increased to 0.806, which was significantly higher than that of OA (P＜0.05). @*Conclusion@#A scientific and efficient HPLC-MS/MS method for the quantitative detection of serum OA is established successfully, which provides a reliable method for the dynamic monitoring of the changes of OA levels in the patients with metabolic diseases.