The aim of this work was to develop a liquid chromatography-tandem mass spectrometry method for the determination of milk allergen and egg allergen in food products.Signature peptides GGLEPINFQTAADQAR,VGINYWLAHK,VLVLD...The aim of this work was to develop a liquid chromatography-tandem mass spectrometry method for the determination of milk allergen and egg allergen in food products.Signature peptides GGLEPINFQTAADQAR,VGINYWLAHK,VLVLDTDYK,FFVAPFPEVFGK,and NAVPITPTLNR were confirmed and synthesized as the quantitative peptide of ovalbumin,α-lactalbumin,β-lactoglobulin,α_(S1)-casein andα_(S2)-casein,the relative isotope-labeled internal standards were used in the quantitative analysis.Linear range was in the range of0.5-5000.0 nmol/L for egg and milk allergen in bread,cake,cookie,rice crust and wheat flour samples with free from egg and milk,the limits of detection of milk allergens and egg allergen were in the range between0.94 mg/100 g and 56.71 mg/100 g,limits of quantification of milk allergens and egg allergen were in the range between 2.36 mg/100 g and 141.78 mg/100 g.The recoveries ranged from 76.7%to 122.8%,the relative standard deviations were in the range of 1.60%-15.60%.The developed method has been successfully used for the detection of egg and milk allergen in various food samples.展开更多
[Objectives]A high performance liquid chromatography-tandem mass spectrometry(HPLC-MS/MS)method was established for the determination of 14β-receptor agonist residues in mutton.[Methods]Samples were hydrolyzed byβ-g...[Objectives]A high performance liquid chromatography-tandem mass spectrometry(HPLC-MS/MS)method was established for the determination of 14β-receptor agonist residues in mutton.[Methods]Samples were hydrolyzed byβ-glucuronidase and extracted with 5%acetic acid-acetonitrile(1:99,V/V)solution.An Eclipse plus C 18 column was used for separation,and the MRM mode was used for qualitative analysis,and the external standard method was used for quantitative analysis of matrix standard solutions.[Results]Under the optimal conditions,the retention time of the 14 kinds ofβ-receptor agonists ranged from 1.0 to 9.5 min.When the mass concentration was in the range of 0.05-0.50μg/ml,the linear relationship ofβ-receptor agonists was good,with correlation coefficients(r)≥0.9992.The detection limits of the method were in the range of 0.04-0.87μg/kg,and the quantitative limits were in the range of 0.35-1.86μg/kg.The average recovery values were in the range of 82.8%-108.9%,with RSDs(n=6)in the range of 1.9%-6.7%.[Conclusions]The method is simple,sensitive,reproducible,accurate,and can be used for simultaneous determination of the 14 kinds ofβ-receptor agonist residues in mutton.展开更多
The measurement of urine catecholamine and metanephrine concentrations is important for biochemical screening and diagnosis of pheochromocytoma.The goal of this work was to develop a simple liquid chromatography-tande...The measurement of urine catecholamine and metanephrine concentrations is important for biochemical screening and diagnosis of pheochromocytoma.The goal of this work was to develop a simple liquid chromatography-tandem mass spectrometry(LC-MS/MS)method for determining catecholamines and metanephrines in urine to replace an existing liquid chromatographic method using electrochemical detection.Urine samples were prepared using Oasis weak-cation-exchange cartridges.The eluate was analyzed on an Agilent ZORBAX Eclipse Plus Phenyl-Hexyl column in 3 min.Adrenaline,noradrenaline,dopamine,metanephrine,normetanephrine,and their deuterated internal standards were monitored in positive electrospray ionization mode by multiple reaction monitoring(MRM).No evidence of ion suppression was observed.The assay was linear up to 5μmol/L for adrenaline,5μmol/L for noradrenaline,6.1μmol/L for dopamine,5.6μmol/L for metanephrine,and 34.6μmol/L for normetanephrine,with lower limits of quantification of 5,5,12,6 and 7nmol/L,respectively.The intra-day and inter-day precisions for all analytes ranged from 0.59%to 4.64%and1.98%to 4.80%,respectively.External quality assurance samples were assayed and showed excellent agreement with the target values.This simple method provides an improved assay for determining urine catecholamines and metanephrines.展开更多
In this experiment,a liquid chromatography tandem mass spectrometry method was built to determine 15 pesticide residues in Chinese cabbage and cucumber samples based on online turbulent flow chromatography purificatio...In this experiment,a liquid chromatography tandem mass spectrometry method was built to determine 15 pesticide residues in Chinese cabbage and cucumber samples based on online turbulent flow chromatography purification.After modified quick,easy,cheap,effective,rugged,and safe(QuEChERS)extraction,extracts were directly injected to the TLX(TurboFlow Liquid Xcalibur)system and brought to TurboFlow™columns for on-line purification and then transferred to analytical column for further separation and analysis.TurboFlow™columns types,transfer flow rate,and transfer time were optimized.Limits of detection and limits of quantification of the method obtained for 15 pesticide residues were ranged between 0.2–1.0μg/kg and 0.5–2.0μg/kg in Chinese cabbage and cucumber samples.Recoveries of pesticide residues were in range of 75.3%–103.7%.Matrix effects for 15 pesticides were in range of 5.6%–106.6%.The developed method has been successfully used for the determination of 15 pesticide residues in real samples.展开更多
Background:Ethoxyquin(EQ)is a common antioxidant which is widely used in animal feed.But the supplement of EQ in animal feed may lead to the residues of EQ and its major oxidation products:ethoxyquin quinone imine(EQI...Background:Ethoxyquin(EQ)is a common antioxidant which is widely used in animal feed.But the supplement of EQ in animal feed may lead to the residues of EQ and its major oxidation products:ethoxyquin quinone imine(EQI)and ethoxyquin dimer(EQDM)in animal tissue.Thus,it would pose potential health hazards to consumers.However,the method for the simultaneous determination of EQ,EQI and EQDM in animal tissues is currently not available,and the accumulation extend of these chemicals in animal tissues after EQ administration remains to be evaluated.Results:A gas chromatography-tandem mass spectrometry method was successfully developed for the simultaneous determination of EQ,EQI and EQDM in swine tissues.The quantitative limits of EQ,EQI and EQDM can achieve to 0.5,5.0 and 5.0μg/kg in swine tissues,respectively.The spiked-recovery ratios of the three analytes(5–2000μg/kg)were in the range of 64.7%–100.7%with relative standard deviations below 11.6%.Moreover,the utilization of this method for the analysis of actual swine tissue samples revealed that the application of commercial EQ additive in swine diet would produce the residues of all the three chemicals(EQ,EQI and EQDM)in fat,kidney,liver and muscle.Conclusions:The assay accuracy and precision of this GC-MS/MS method can meet the requirement of quantitative analysis.Meanwhile,the safety of EQ as a feed additive should be seriously considered with regard to food safety concerns since the oxidation product of EQ may have potential carcinogenicity.展开更多
Over the past decade, the use of hair specimens for the long-term detection of the alcohol biomarker ethyl glucuronide has been increasing in popularity and usage. We evaluated the usefulness of fingernail clippings a...Over the past decade, the use of hair specimens for the long-term detection of the alcohol biomarker ethyl glucuronide has been increasing in popularity and usage. We evaluated the usefulness of fingernail clippings as a suitable alterna-tive to hair for ethyl glucuronide detection. A liquid chromatography-tandem mass spectrometry method for the detection of ethyl glucuronide in fingernail clippings was fully validated and used to analyze the hair and/or fingernail specimens of 606 college-aged study participants. The limit of detection was 2 pg/mg, the limit of quantitation was 8 pg/mg and the method was linear from 8 to 2000 pg/mg. Intra- and inter-assay imprecision studies at three different concentrations (20, 40, 200 pg/mg) were all within 7.8% and all intra- and inter-assay bias studies at these levels were within 115.1% of target concentration. Ethyl glucuronide levels in fingernail (mean = 29.1 ± 55.6 pg/mg) were higher than ethyl glucuronide levels in hair (mean = 9.48 ± 22.3 pg/mg) and a correlation of the matched pairs was observed (r = 0.552, P < 0.01, n = 529). Evaluating each gender separately revealed that the correlation of male fingernail to male hair was large and significant (r = 0.782, P < 0.01, n = 195) while female hair to female fingernail was small yet sig-nificant (r = 0.249, P < 0.01, n = 334). The study results demonstrated that fingernail may be a suitable alternative to hair for ethyl glucuronide detection and may be the preferred sample type due to the lack of a gender bias.展开更多
Five thyreostats(TSs),namely tapazole,thiouracil,methylthiouracil,propylthiouracil,and phenylthiouracil,were determined in bovine urine using ultra-high performance liquid chromatography-tandem mass spectrometry(UHPLC...Five thyreostats(TSs),namely tapazole,thiouracil,methylthiouracil,propylthiouracil,and phenylthiouracil,were determined in bovine urine using ultra-high performance liquid chromatography-tandem mass spectrometry(UHPLC-MS/MS)in positive electrospray ionization mode.Extraction and clean-up were achieved using a ChemElut cartridge with tert-butyl methyl ether,without a derivatization step.Separation was achieved on an Acquity UPLC SS T3 column.The mobile phase was acetonitrile and water containing 0.2%(v/v)formic acid.The mass spectrometer was operated in multiple reaction monitoring mode.Urine samples were spiked with TS solution at levels corresponding to 5,10,15,and 20μg/L.The accuracy(internal standard corrected)ranged from 92%to 107%,with a repeatability precision(relative standard deviation,RSD)less than 15%for all five analytes.The RSDs within-laboratory reproducibility was less than 26%.The decision limits(CCα)and detection capabilities(CCβ)were obtained from a calibration curve and were in the ranges of 3.1-6.1μg/L and 4.0-7.4μg/L,respectively.The CCαand CCβvalues were below the recommended concentration,which was set at 10μg/L.The results show that the described method is suitable for the direct detection of TSs in bovine urine.This method can also be used to determine TSs in porcine urine.展开更多
Objective To establish a rapid,sensitive and selective liquid chromatography-tandem mass spectrometry (LC-MS/MS) method for the determination of acyclovir (the metabolite of valacyclovir hydrochloride) in human plasma...Objective To establish a rapid,sensitive and selective liquid chromatography-tandem mass spectrometry (LC-MS/MS) method for the determination of acyclovir (the metabolite of valacyclovir hydrochloride) in human plasma. Methods After addition of ganciclovir as internal standard (IS),plasma samples were prepared by one-step protein precipitation using acetonitrile as precipitant,followed by an isocratic elution with 0.1% formic acid solution-methanol (95∶5,v/v) on an Agilent ZORBAX SB-C18 (150mm×2.1mm i.d.,3.5μm) column. Detection was performed on a triple-quadrupole mass spectrometer utilizing electrospray ionization (ESI) interface operating in positive ion and selected reaction monitoring (SRM) mode with the precursor to product ion transitions m/z 226.2→152.1 for acyclovir and m/z 256.2→152.1 for the IS. Results The analytical results demonstrated a good linearity over the ranges from 0.005 to 4μg/mL (r=0.9999) for valacyclovir hydrochloride. The relative standard deviations (RSD) of intra-batch and inter-batch were less than 4.06% and 9.23%,respectively. The limit of detection and lower limit of quantification in human plasma were 2ng/mL and 5ng/mL,respectively. Conclusion The method was simple,sensitive,accurate and reproducible and has been successfully applied to a bioequivalence study of valacyclovir hydrochloride capsules in Chinese healthy male volunteers.展开更多
A method of rapidly detecting three kinds of microcystins( MCs) in environmental water samples by using disk SPE- ultra high performance liquid chromatography- tandem mass spectrometry( UPLC- MS / MS) was established....A method of rapidly detecting three kinds of microcystins( MCs) in environmental water samples by using disk SPE- ultra high performance liquid chromatography- tandem mass spectrometry( UPLC- MS / MS) was established. Firstly,environmental water samples were extracted by disk SPE column( C_(18)),and three kinds of MCs were separated by Waters BEH C_(18) chromatographic column with acetonitrile- 0. 2% formic acid solution as the mobile phase. After the gradient elution separation,the external standard method was used for quantitative and qualitative analysis under MRM of UPLC- MS / MS. The results showed that the three kinds of MCs in the range of 0. 05- 10 μg / L showed good linear relation,and the correlation coefficients were higher than 0. 999 4,while the method detection limit was 0. 04 ng / L. Under 0. 1,1,and 5 μg / L standard addition for the same environmental sample,the average recovery was 82. 8%- 108. 8%,and the relative standard deviation of determination results was2. 1%- 10. 1%( n = 6). This method is rapid,sensitive and accurate,so it can be effectively applied in the monitoring of MCs in environmental water samples.展开更多
[Objectives]This study was conducted to establish an ultra-high performance liquid chromatography-tandem mass spectrometry for the rapid extraction of sodium pentachlorophenoxide from animal-derived food.[Methods]The ...[Objectives]This study was conducted to establish an ultra-high performance liquid chromatography-tandem mass spectrometry for the rapid extraction of sodium pentachlorophenoxide from animal-derived food.[Methods]The samples were extracted with an acetonitrile water solution(8∶2),0.1 mol/L hydrochloric acid and a purification extraction bag with shaking.Centrifugation was performed to obtain supernatants,which were added to purification tubes containing PSA and C_(18) for purification,and then filtered with membranes for determination.Each test solution was separated by a ZORBAX Eclipse plus C_(18) column with acetonitrile and 5 mmol/L ammonium acetate as mobile phases,and determined with electrospray ionization and multiple reaction monitoring.[Results]The method had good linearity in the concentration range of 1.0-50 ng/ml,and the correlation coefficient was 0.9997.The limit of detection was 0.25μg/kg and the limit of quantification was 0.75μg/kg.The recovery was between 87.4%and 112.5%,and the RSD%was between 0.5%and 10.0%.[Conclusions]The method has simple operation and high sensitivity,and is suitable for trace detection of sodium pentachlorophenoxide in large quantities of animal-derived food.展开更多
A highly sensitive ultra-high performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) method was developed for the quantification of vancomycin (VAN) in low volumes of rabbit serum. For each analysis,...A highly sensitive ultra-high performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) method was developed for the quantification of vancomycin (VAN) in low volumes of rabbit serum. For each analysis, 2 μL rabbit serum was precipitated with methanol that contained the internal standard teicoplanin (TEI). The supernatant was transferred into a 384 well-plate, diluted with water, covered with a pierceable silicone mat and 5 μL was analyzed in positive ionization mode. The UHPLC-MS/MS consisted of an Agilent 1290 Infinity UHPLC system connected to an AB Sciex QTrap®5500 hybrid linear ion-trap triple quadrupole mass spectrometer equipped with a Turbo Spray source. Chromatographic separation was achieved using a Waters Acquity UPLC BEH C18 (1.7 μm, 2.1 mm × 100 mm) column, a VanGuard (1.7 μm, 2.1 × 5 mm) guard column and a mobile phase of water and methanol both containing 5 mM ammonium acetate with 0.1% formic acid. VAN was quantified with multiple reaction monitoring using the transitions of m/z 725.5/144.2, and TEI was monitored at m/z 940.6/316.4. The accuracy, precision, linearity, range and lower limit of quantification (LLOQ) were determined. The accuracy was ≤9.93% and the precision was ≤10.6%. The range was established as 0.1 to 40 μg·mL-1. The LLOQ was 0.1 μg·mL-1 VAN requiring 2 μL of sample with an accuracy of -20.2% and precision of 8.39%. The method was applied successfully to determine the VAN concentrations in rabbit serum after the i.v. administration of VAN via implanted ear catheters.展开更多
A sensitive and reliable method was developed and validated for the simu1taneous determination of 6 carbamate pesticides and relevant metabolites based on the modified fast QuEChERS(quick,easy,cheap,effective,rugged a...A sensitive and reliable method was developed and validated for the simu1taneous determination of 6 carbamate pesticides and relevant metabolites based on the modified fast QuEChERS(quick,easy,cheap,effective,rugged and safe)method combined with ultra-performance 1iquid chromatography-tandem mass spectrometry(UPLC-MS/MS).The method was also applied in the analysis of 23 commonly consumed oilseeds and oil samples.The sample was extracted with acetonitrile for three times and then the extracted solution was filtered directly though 250 mg precipitated silica adsorbent(PSA)and 250 mg Cis The mobile phase was water(containing 0.1%formic acid)and acetonitrile.The extemal standard protocols were adopted to validate the method in terms of recovery,1inearity,precision,sensitivity,and relative standard deviation(RSD)under the optimized conditions.The linear calibration curves with different ranges were established with R^(2)>0.9973,limit of detections(LODs)ranged from 0.100μg/kg to 20000μg/kg and limit of quantitations(LOQs)ranged from 0.300μg/kg to 6.000μg/kg.The LODs meets the detection requirement for the maximum residue limits in practical samples.Meanwhile,the recoveries ranged from 60.2%to 116.6%with associated RSDs ranged from 0.33%to 5.35%in 10 oilseeds matrices and ranged from 61.9%to 116.9%with RSDs ranged from 0.30%to 5.02%in 13 oil matrices.These features do make the UPLC-MSMS an ideal analytical platform for accurate and high throughput analysis of carbamates residues in the complex matrix.展开更多
A high performance liquid chromatography-tandem mass spectrometry(HPLC-MS/MS)method was built to determine icarside,hyperoside and psoralen in food.The samples were extracted with 70%methanol,the solid and semi-solid ...A high performance liquid chromatography-tandem mass spectrometry(HPLC-MS/MS)method was built to determine icarside,hyperoside and psoralen in food.The samples were extracted with 70%methanol,the solid and semi-solid hotpot seasoning samples were purified by solid phase extraction column,and then determined by HPLC-MS/MS.Acetonitrile and 0.1%formic acid solution were used as the mobile phase,and the gradient elution was adopted for analysis.As shown in the results,the analytes had good linearity in the range of 0.05−100 ng/mL,and the correlation coeffificients(R^(2))were greater than 0.999.In this method,the limits of quantitation(LOQ)of psoralen,icariside and hyperoside in liquid samples were 1.25,25.0 and 12.5μg/L respectively;while the LOQs of psoralen,icariside and hyperoside in solid samples and hotpot seasoning samples were 1.25,25.0 and 12.5μg/kg,respectively.The liquid beverage,solid beverage,health food(in the form of oral liquid,capsule,tablet),integrated alcoholic beverage and solid hotpot seasoning were selected as representative samples and used for method validation.The average spiked recoveries at 3 levels(LOQ,2 LOQ,10 LOQ)were in the range of 83.7%−115.0%,and the relative standard deviations were in range of 0.5%−9.4%(n=6).The method is rapid,accurate and sensitive,which is suitable for the simultaneous determination of icariside,hyperoside and psoralen in different food matrices.展开更多
This study aimed to characterize and identify calcium-chelating peptides from rabbit bone collagen and explore the underlying chelating mechanism.Collagen peptides and calcium were extracted from rabbit bone by instan...This study aimed to characterize and identify calcium-chelating peptides from rabbit bone collagen and explore the underlying chelating mechanism.Collagen peptides and calcium were extracted from rabbit bone by instant ejection steam explosion(ICSE)combined with enzymatic hydrolysis,followed by chelation reaction to prepare rabbit bone peptide-calcium chelate(RBCP-Ca).The chelating sites were further analyzed by liquid chromatography-tandem mass(LC-MS/MS)spectrometry while the chelating mechanism and binding modes were investigated.The structural characterization revealed that RBCP successfully chelated with calcium ions.Furthermore,LC-MS/MS analysis indicated that the binding sites included both acidic amino acids(Asp and Glu)and basic amino acids(Lys and Arg),Interestingly,three binding modes,namely Inter-Linking,Loop-Linking and Mono-Linking were for the first time found,while Inter-Linking mode accounted for the highest proportion(75.1%),suggesting that chelation of calcium ions frequently occurred between two peptides.Overall,this study provides a theoretical basis for the elucidation of chelation mechanism of calcium-chelating peptides.展开更多
BACKGROUND As a well-known fact to the public,gestational diabetes mellitus(GDM)could bring serious risks for both pregnant women and infants.During this important investigation into the linkage between GDM patients a...BACKGROUND As a well-known fact to the public,gestational diabetes mellitus(GDM)could bring serious risks for both pregnant women and infants.During this important investigation into the linkage between GDM patients and their altered expression in the serum,proteomics techniques were deployed to detect the differentially expressed proteins(DEPs)of in the serum of GDM patients to further explore its pathogenesis,and find out possible biomarkers to forecast GDM occurrence.METHODS Subjects were divided into GDM and normal control groups according to the IADPSG diagnostic criteria.Serum samples were randomly selected from four cases in each group at 24-28 wk of gestation,and the blood samples were identified by applying iTRAQ technology combined with liquid chromatography-tandem mass spectrometry.Key proteins and signaling pathways associated with GDM were identified by bioinformatics analysis,and the expression of key proteins in serum from 12 wk to 16 wk of gestation was further verified using enzyme-linked immunosorbent assay (ELISA).RESULTS Forty-seven proteins were significantly differentially expressed by analyzing the serum samples between the GDMgravidas as well as the healthy ones. Among them, 31 proteins were found to be upregulated notably and the rest16 proteins were downregulated remarkably. Bioinformatic data report revealed abnormal expression of proteinsassociated with lipid metabolism, coagulation cascade activation, complement system and inflammatory responsein the GDM group. ELISA results showed that the contents of RBP4, as well as ANGPTL8, increased in the serumof GDM gravidas compared with the healthy ones, and this change was found to initiate from 12 wk to 16 wk ofgestation.CONCLUSION GDM symptoms may involve abnormalities in lipid metabolism, coagulation cascade activation, complementsystem and inflammatory response. RBP4 and ANGPTL8 are expected to be early predictors of GDM.展开更多
[Objectives]This study was conducted to explore the occurrence levels of endocrine disruptors(EDCs)in rural areas around a county landfill in Tongren City.[Methods]The water around the landfill was sampled and analyze...[Objectives]This study was conducted to explore the occurrence levels of endocrine disruptors(EDCs)in rural areas around a county landfill in Tongren City.[Methods]The water around the landfill was sampled and analyzed.A solid-phase extraction and high performance liquid chromatography-tandem mass spectrometry(SPE-UPLC-MS/MS)method was established for the determination of 27 EDCs.After the HLB solid-phase extraction column was activated,a water sample,which was adjusted with phosphoric acid to a pH of 2(±0.5)and added with 500 mg of disodium EDTA,was loaded,and 5 ml of water and 20%methanol water was added for washing.Next,10 ml of elution solution was added for elution,and the collected eluate was evaporated under reduced pressure at 40℃to near dryness,and 1 ml of reconstitution solution was added to a constant volume.An ACQUITY UPLC BEH C18(100×2.1 mm,2.6μm)chromatographic column was adopted for LC separation by gradient elution with pure water solution-acetonitrile as the mobile phase.For MS detection,the MRM mode was adopted for collection,and the positive and negative ion modes were switched for simultaneous determination,and the internal standard method was used for quantification.[Results]The correlation coefficient R2 was greater than 0.99 in the linear range of each target substance.The limits of quantitation in the method were between 0.05 and 2.00 ng/L,and the recoveries ranged from 75.3%to 105.7%.[Conclusions]The method has high sensitivity,good accuracy and strong practical value.展开更多
Research on pollution characteristics and toxicities of emerging polycyclic aromatic sulfur heterocycles(PASHs) in PM_(2.5) has not been reported due to the lack of analytical method with the needed performance.In the...Research on pollution characteristics and toxicities of emerging polycyclic aromatic sulfur heterocycles(PASHs) in PM_(2.5) has not been reported due to the lack of analytical method with the needed performance.In the present study,a novel method for the determination of 14 PASHs in PM_(2.5) was developed using atmospheric pressure gas chro matography-tandem mass spectrometry(APGC-MS/MS).Atmospheric pressure chemical ionization was operated with multiple reaction monitoring in positive ionization mode.High sensitivity(method detection limit <1.673 pg/m^(3)),acceptable re coveries(67.6%-120.8%) and precisions(RSD of 2.2%-15.4%) were obtained.The method was successfully applied for analyzing PASHs in 10 PM_(2.5) samples collected from Taiyuan,a typical industrial city in China,in 2016,The total concentrations were from 929 pg/m^(3) to 14,593 pg/m^(3).The determined levels indicated that further investigations on environmental fate and toxicities of PM_(2.5)-bound PASHs may be needed.展开更多
A liquid chromatography-tandem mass spectrometry method was established for the determination of ingredients of chicken,duck,pork,beef and mutton.A total of 19 characteristic peptides were screened out from 5 kinds of...A liquid chromatography-tandem mass spectrometry method was established for the determination of ingredients of chicken,duck,pork,beef and mutton.A total of 19 characteristic peptides were screened out from 5 kinds of meat,and a liquid chromatography-tandem mass spectrometry method was established for the determination of characteristic peptides.The accuracy of the method was tested by adding duck,pork and chicken with the mass fractions of 0.5%,1%and 5%to mutton,pork and chicken with the mass fractions of 0.5%,1%and 5%to beef,and duck with the mass fractions of 1%,2%and 10%to beef.The results show that the method has high accuracy and stability,and could be used to determine the content of 3 kinds of adulterated meat components in mutton and beef samples.展开更多
A precise and reliable analytical method of high performance liquid chromatography-tandem mass spectrometry(HPLCMS/MS)was developed to measure trace levels of enrofloxacin(ENR)and its major metabolite ciprofloxacin(CI...A precise and reliable analytical method of high performance liquid chromatography-tandem mass spectrometry(HPLCMS/MS)was developed to measure trace levels of enrofloxacin(ENR)and its major metabolite ciprofloxacin(CIP)in carp tissues.Optimized chromatographic separation was obtained on a Waters Xterra MS C_(18) reversed-phase column using gradient elution with methanol and 0.1%formic acid aqueous solution including 5mmolL^(-1) of ammonium acetate.The established method was applied to study the pharmacokinetics and distribution of ENR and CIP in tissues of carp following a single oral administration in feed at a dosage of 40mgkg^(-1) bw(body weight).Data were analyzed using DAS 2.0 dynamics software,and the experimental results suggest that ENR was rapidly absorbed and extensively distributed in carp tissues through systemic circulation,and the pharmacokinetic characteristics can be described with a two-compartment model.The elimination half-lives(t_(1/2β))from muscle,liver,gill,plasma and skin were 131,160,104,132 and 310 h,respectively.The areas under the drug concentration-time curves(AUC)for these tissues were 491,972,750,249 and 706hmgkg^(-1),respectively.The maximum concentration(C_(max))values were 13,29,37,9 and 5mgkg^(-1) with peak times(t_(max))of 8,4,4,2 and 4 h,respectively.Ciprofloxacin,the active metabolite of ENR,was also detected in carp tissues,indicating that only 1.54%of de-ethylation of ENR occurs in carp.At a water temperature of 18℃,the drug withdrawal time was determined to be no less than 24 d while the carp was fed at a single dosage of 40mgkg^(-1).展开更多
This study aimed to explore the anti-bacterial and anti-fungal activities of extracts from different parts of plants in the Zingiberaceae family.The inhibitory rate,minimum inhibitory concentration(MIC),and minimum ba...This study aimed to explore the anti-bacterial and anti-fungal activities of extracts from different parts of plants in the Zingiberaceae family.The inhibitory rate,minimum inhibitory concentration(MIC),and minimum bactericidal concentration(MBC)of leaf and stem,and root and rhizome extracts from Alpinia katsumadai Hayata,Alpinia oxyphylla Miq×Alpinia henryi K.Schumann,Alpinia oblongifolia Hayata,Alpinia nigra(Gaertn.)Burtt,Amomum villosum Lour,Alpinia zerumbet(Pers.)Burtt.et Smith and Alpinia oxyphylla Miq were determined using the fungus cake method and double dilution method.The seven Zingiberaceae plants exhibited characteristic antibacterial activities against pathogenic bacteria and fungi.At a 1.5 mg mL^(−1),A.zerumbet root and rhizome extracts exhibited strong inhibitory activity against S.aureus and E.coli,with 83.23%and 79.62%,respectively.In addition,A.zerumbet leaf and stem extracts had an inhibitory rate of 90.85%against P.aeruginosa.At the same concentration,the leaf and stem,root and rhizome extracts of A.katsumadai had the best anti-bacterial effect against F.oxysporum,with inhibition rates of 84.46%and 84.73%,respectively.Moreover,A.katsumadai and A.zerumbet leaf and stem extracts had the most significant antibacterial effect against S.aureus,with a MIC of 0.063 mg mL^(−1).Thus,both A.katsumadai and A.zerumbet extracts had significant antibacterial activity.In addition,by comparing the inhibitory effect of extracts from different parts,it was found that the inhibitory rate and average inhibitory rate of extracts from leaf and stem were higher than those from root and rhizome.The chemical constituents of A.katsumadai and A.zerumbet,determined by the high-performance liquid chromatography-tandem mass spectrometry(UPLC-MS/MS),revealed that citric acid(CA),alpinetin,and pinocembrin(PNCB)were the functional constituents yielding the antibacterial activity.Overall,A.katsumadai and A.zerumbet have the potential to be developed as new plant fungicides and bactericides.展开更多
基金supported by National Key Research and Development Program of China(2019YFC1606400)Science and Technology Project of State Administration for Market Regulation(2021MK023)+1 种基金Hebei Province High-level Talent Funding Program(A201901008)Research Project of Hebei Administration for Market Regulation(2020ZD12)。
文摘The aim of this work was to develop a liquid chromatography-tandem mass spectrometry method for the determination of milk allergen and egg allergen in food products.Signature peptides GGLEPINFQTAADQAR,VGINYWLAHK,VLVLDTDYK,FFVAPFPEVFGK,and NAVPITPTLNR were confirmed and synthesized as the quantitative peptide of ovalbumin,α-lactalbumin,β-lactoglobulin,α_(S1)-casein andα_(S2)-casein,the relative isotope-labeled internal standards were used in the quantitative analysis.Linear range was in the range of0.5-5000.0 nmol/L for egg and milk allergen in bread,cake,cookie,rice crust and wheat flour samples with free from egg and milk,the limits of detection of milk allergens and egg allergen were in the range between0.94 mg/100 g and 56.71 mg/100 g,limits of quantification of milk allergens and egg allergen were in the range between 2.36 mg/100 g and 141.78 mg/100 g.The recoveries ranged from 76.7%to 122.8%,the relative standard deviations were in the range of 1.60%-15.60%.The developed method has been successfully used for the detection of egg and milk allergen in various food samples.
基金Supported by The Fourth Batch of High-end Talent Project in Hebei ProvinceTangshan Science and Technology Entrepreneurship and Innovation Leading Talent Project(21130243A).
文摘[Objectives]A high performance liquid chromatography-tandem mass spectrometry(HPLC-MS/MS)method was established for the determination of 14β-receptor agonist residues in mutton.[Methods]Samples were hydrolyzed byβ-glucuronidase and extracted with 5%acetic acid-acetonitrile(1:99,V/V)solution.An Eclipse plus C 18 column was used for separation,and the MRM mode was used for qualitative analysis,and the external standard method was used for quantitative analysis of matrix standard solutions.[Results]Under the optimal conditions,the retention time of the 14 kinds ofβ-receptor agonists ranged from 1.0 to 9.5 min.When the mass concentration was in the range of 0.05-0.50μg/ml,the linear relationship ofβ-receptor agonists was good,with correlation coefficients(r)≥0.9992.The detection limits of the method were in the range of 0.04-0.87μg/kg,and the quantitative limits were in the range of 0.35-1.86μg/kg.The average recovery values were in the range of 82.8%-108.9%,with RSDs(n=6)in the range of 1.9%-6.7%.[Conclusions]The method is simple,sensitive,reproducible,accurate,and can be used for simultaneous determination of the 14 kinds ofβ-receptor agonist residues in mutton.
文摘The measurement of urine catecholamine and metanephrine concentrations is important for biochemical screening and diagnosis of pheochromocytoma.The goal of this work was to develop a simple liquid chromatography-tandem mass spectrometry(LC-MS/MS)method for determining catecholamines and metanephrines in urine to replace an existing liquid chromatographic method using electrochemical detection.Urine samples were prepared using Oasis weak-cation-exchange cartridges.The eluate was analyzed on an Agilent ZORBAX Eclipse Plus Phenyl-Hexyl column in 3 min.Adrenaline,noradrenaline,dopamine,metanephrine,normetanephrine,and their deuterated internal standards were monitored in positive electrospray ionization mode by multiple reaction monitoring(MRM).No evidence of ion suppression was observed.The assay was linear up to 5μmol/L for adrenaline,5μmol/L for noradrenaline,6.1μmol/L for dopamine,5.6μmol/L for metanephrine,and 34.6μmol/L for normetanephrine,with lower limits of quantification of 5,5,12,6 and 7nmol/L,respectively.The intra-day and inter-day precisions for all analytes ranged from 0.59%to 4.64%and1.98%to 4.80%,respectively.External quality assurance samples were assayed and showed excellent agreement with the target values.This simple method provides an improved assay for determining urine catecholamines and metanephrines.
基金National Key Research and Development Program of China(Project No.2018YFC1603400)Science and Technology Program of Hebei Province(Project No.19225503D)Technical Support Project of State Administration for Market Regulation(Project No.2019YJ009).
文摘In this experiment,a liquid chromatography tandem mass spectrometry method was built to determine 15 pesticide residues in Chinese cabbage and cucumber samples based on online turbulent flow chromatography purification.After modified quick,easy,cheap,effective,rugged,and safe(QuEChERS)extraction,extracts were directly injected to the TLX(TurboFlow Liquid Xcalibur)system and brought to TurboFlow™columns for on-line purification and then transferred to analytical column for further separation and analysis.TurboFlow™columns types,transfer flow rate,and transfer time were optimized.Limits of detection and limits of quantification of the method obtained for 15 pesticide residues were ranged between 0.2–1.0μg/kg and 0.5–2.0μg/kg in Chinese cabbage and cucumber samples.Recoveries of pesticide residues were in range of 75.3%–103.7%.Matrix effects for 15 pesticides were in range of 5.6%–106.6%.The developed method has been successfully used for the determination of 15 pesticide residues in real samples.
基金supported the Ministry of Agriculture of the People’s Republic of China.
文摘Background:Ethoxyquin(EQ)is a common antioxidant which is widely used in animal feed.But the supplement of EQ in animal feed may lead to the residues of EQ and its major oxidation products:ethoxyquin quinone imine(EQI)and ethoxyquin dimer(EQDM)in animal tissue.Thus,it would pose potential health hazards to consumers.However,the method for the simultaneous determination of EQ,EQI and EQDM in animal tissues is currently not available,and the accumulation extend of these chemicals in animal tissues after EQ administration remains to be evaluated.Results:A gas chromatography-tandem mass spectrometry method was successfully developed for the simultaneous determination of EQ,EQI and EQDM in swine tissues.The quantitative limits of EQ,EQI and EQDM can achieve to 0.5,5.0 and 5.0μg/kg in swine tissues,respectively.The spiked-recovery ratios of the three analytes(5–2000μg/kg)were in the range of 64.7%–100.7%with relative standard deviations below 11.6%.Moreover,the utilization of this method for the analysis of actual swine tissue samples revealed that the application of commercial EQ additive in swine diet would produce the residues of all the three chemicals(EQ,EQI and EQDM)in fat,kidney,liver and muscle.Conclusions:The assay accuracy and precision of this GC-MS/MS method can meet the requirement of quantitative analysis.Meanwhile,the safety of EQ as a feed additive should be seriously considered with regard to food safety concerns since the oxidation product of EQ may have potential carcinogenicity.
文摘Over the past decade, the use of hair specimens for the long-term detection of the alcohol biomarker ethyl glucuronide has been increasing in popularity and usage. We evaluated the usefulness of fingernail clippings as a suitable alterna-tive to hair for ethyl glucuronide detection. A liquid chromatography-tandem mass spectrometry method for the detection of ethyl glucuronide in fingernail clippings was fully validated and used to analyze the hair and/or fingernail specimens of 606 college-aged study participants. The limit of detection was 2 pg/mg, the limit of quantitation was 8 pg/mg and the method was linear from 8 to 2000 pg/mg. Intra- and inter-assay imprecision studies at three different concentrations (20, 40, 200 pg/mg) were all within 7.8% and all intra- and inter-assay bias studies at these levels were within 115.1% of target concentration. Ethyl glucuronide levels in fingernail (mean = 29.1 ± 55.6 pg/mg) were higher than ethyl glucuronide levels in hair (mean = 9.48 ± 22.3 pg/mg) and a correlation of the matched pairs was observed (r = 0.552, P < 0.01, n = 529). Evaluating each gender separately revealed that the correlation of male fingernail to male hair was large and significant (r = 0.782, P < 0.01, n = 195) while female hair to female fingernail was small yet sig-nificant (r = 0.249, P < 0.01, n = 334). The study results demonstrated that fingernail may be a suitable alternative to hair for ethyl glucuronide detection and may be the preferred sample type due to the lack of a gender bias.
文摘Five thyreostats(TSs),namely tapazole,thiouracil,methylthiouracil,propylthiouracil,and phenylthiouracil,were determined in bovine urine using ultra-high performance liquid chromatography-tandem mass spectrometry(UHPLC-MS/MS)in positive electrospray ionization mode.Extraction and clean-up were achieved using a ChemElut cartridge with tert-butyl methyl ether,without a derivatization step.Separation was achieved on an Acquity UPLC SS T3 column.The mobile phase was acetonitrile and water containing 0.2%(v/v)formic acid.The mass spectrometer was operated in multiple reaction monitoring mode.Urine samples were spiked with TS solution at levels corresponding to 5,10,15,and 20μg/L.The accuracy(internal standard corrected)ranged from 92%to 107%,with a repeatability precision(relative standard deviation,RSD)less than 15%for all five analytes.The RSDs within-laboratory reproducibility was less than 26%.The decision limits(CCα)and detection capabilities(CCβ)were obtained from a calibration curve and were in the ranges of 3.1-6.1μg/L and 4.0-7.4μg/L,respectively.The CCαand CCβvalues were below the recommended concentration,which was set at 10μg/L.The results show that the described method is suitable for the direct detection of TSs in bovine urine.This method can also be used to determine TSs in porcine urine.
文摘Objective To establish a rapid,sensitive and selective liquid chromatography-tandem mass spectrometry (LC-MS/MS) method for the determination of acyclovir (the metabolite of valacyclovir hydrochloride) in human plasma. Methods After addition of ganciclovir as internal standard (IS),plasma samples were prepared by one-step protein precipitation using acetonitrile as precipitant,followed by an isocratic elution with 0.1% formic acid solution-methanol (95∶5,v/v) on an Agilent ZORBAX SB-C18 (150mm×2.1mm i.d.,3.5μm) column. Detection was performed on a triple-quadrupole mass spectrometer utilizing electrospray ionization (ESI) interface operating in positive ion and selected reaction monitoring (SRM) mode with the precursor to product ion transitions m/z 226.2→152.1 for acyclovir and m/z 256.2→152.1 for the IS. Results The analytical results demonstrated a good linearity over the ranges from 0.005 to 4μg/mL (r=0.9999) for valacyclovir hydrochloride. The relative standard deviations (RSD) of intra-batch and inter-batch were less than 4.06% and 9.23%,respectively. The limit of detection and lower limit of quantification in human plasma were 2ng/mL and 5ng/mL,respectively. Conclusion The method was simple,sensitive,accurate and reproducible and has been successfully applied to a bioequivalence study of valacyclovir hydrochloride capsules in Chinese healthy male volunteers.
文摘A method of rapidly detecting three kinds of microcystins( MCs) in environmental water samples by using disk SPE- ultra high performance liquid chromatography- tandem mass spectrometry( UPLC- MS / MS) was established. Firstly,environmental water samples were extracted by disk SPE column( C_(18)),and three kinds of MCs were separated by Waters BEH C_(18) chromatographic column with acetonitrile- 0. 2% formic acid solution as the mobile phase. After the gradient elution separation,the external standard method was used for quantitative and qualitative analysis under MRM of UPLC- MS / MS. The results showed that the three kinds of MCs in the range of 0. 05- 10 μg / L showed good linear relation,and the correlation coefficients were higher than 0. 999 4,while the method detection limit was 0. 04 ng / L. Under 0. 1,1,and 5 μg / L standard addition for the same environmental sample,the average recovery was 82. 8%- 108. 8%,and the relative standard deviation of determination results was2. 1%- 10. 1%( n = 6). This method is rapid,sensitive and accurate,so it can be effectively applied in the monitoring of MCs in environmental water samples.
文摘[Objectives]This study was conducted to establish an ultra-high performance liquid chromatography-tandem mass spectrometry for the rapid extraction of sodium pentachlorophenoxide from animal-derived food.[Methods]The samples were extracted with an acetonitrile water solution(8∶2),0.1 mol/L hydrochloric acid and a purification extraction bag with shaking.Centrifugation was performed to obtain supernatants,which were added to purification tubes containing PSA and C_(18) for purification,and then filtered with membranes for determination.Each test solution was separated by a ZORBAX Eclipse plus C_(18) column with acetonitrile and 5 mmol/L ammonium acetate as mobile phases,and determined with electrospray ionization and multiple reaction monitoring.[Results]The method had good linearity in the concentration range of 1.0-50 ng/ml,and the correlation coefficient was 0.9997.The limit of detection was 0.25μg/kg and the limit of quantification was 0.75μg/kg.The recovery was between 87.4%and 112.5%,and the RSD%was between 0.5%and 10.0%.[Conclusions]The method has simple operation and high sensitivity,and is suitable for trace detection of sodium pentachlorophenoxide in large quantities of animal-derived food.
基金supported by the operating grant of the Collaborative Health Research Project,Natural Sciences and Engineering Research Council of Canada,and Canadian Institute of Health Research(CHRPJ 385967).
文摘A highly sensitive ultra-high performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) method was developed for the quantification of vancomycin (VAN) in low volumes of rabbit serum. For each analysis, 2 μL rabbit serum was precipitated with methanol that contained the internal standard teicoplanin (TEI). The supernatant was transferred into a 384 well-plate, diluted with water, covered with a pierceable silicone mat and 5 μL was analyzed in positive ionization mode. The UHPLC-MS/MS consisted of an Agilent 1290 Infinity UHPLC system connected to an AB Sciex QTrap®5500 hybrid linear ion-trap triple quadrupole mass spectrometer equipped with a Turbo Spray source. Chromatographic separation was achieved using a Waters Acquity UPLC BEH C18 (1.7 μm, 2.1 mm × 100 mm) column, a VanGuard (1.7 μm, 2.1 × 5 mm) guard column and a mobile phase of water and methanol both containing 5 mM ammonium acetate with 0.1% formic acid. VAN was quantified with multiple reaction monitoring using the transitions of m/z 725.5/144.2, and TEI was monitored at m/z 940.6/316.4. The accuracy, precision, linearity, range and lower limit of quantification (LLOQ) were determined. The accuracy was ≤9.93% and the precision was ≤10.6%. The range was established as 0.1 to 40 μg·mL-1. The LLOQ was 0.1 μg·mL-1 VAN requiring 2 μL of sample with an accuracy of -20.2% and precision of 8.39%. The method was applied successfully to determine the VAN concentrations in rabbit serum after the i.v. administration of VAN via implanted ear catheters.
基金This work was supported by the Postdoctoral Science Foundation of Anhui Province(2020B412),the project of Science and Technology Program of State Administration for Market Regulation(2020MK049)the project of Science and Technology Program of Administration for Market Regulation of Anhui Province(2019MK037).
文摘A sensitive and reliable method was developed and validated for the simu1taneous determination of 6 carbamate pesticides and relevant metabolites based on the modified fast QuEChERS(quick,easy,cheap,effective,rugged and safe)method combined with ultra-performance 1iquid chromatography-tandem mass spectrometry(UPLC-MS/MS).The method was also applied in the analysis of 23 commonly consumed oilseeds and oil samples.The sample was extracted with acetonitrile for three times and then the extracted solution was filtered directly though 250 mg precipitated silica adsorbent(PSA)and 250 mg Cis The mobile phase was water(containing 0.1%formic acid)and acetonitrile.The extemal standard protocols were adopted to validate the method in terms of recovery,1inearity,precision,sensitivity,and relative standard deviation(RSD)under the optimized conditions.The linear calibration curves with different ranges were established with R^(2)>0.9973,limit of detections(LODs)ranged from 0.100μg/kg to 20000μg/kg and limit of quantitations(LOQs)ranged from 0.300μg/kg to 6.000μg/kg.The LODs meets the detection requirement for the maximum residue limits in practical samples.Meanwhile,the recoveries ranged from 60.2%to 116.6%with associated RSDs ranged from 0.33%to 5.35%in 10 oilseeds matrices and ranged from 61.9%to 116.9%with RSDs ranged from 0.30%to 5.02%in 13 oil matrices.These features do make the UPLC-MSMS an ideal analytical platform for accurate and high throughput analysis of carbamates residues in the complex matrix.
基金This work was supported by National Key Research and Development Program of China(2019YFC1606400).
文摘A high performance liquid chromatography-tandem mass spectrometry(HPLC-MS/MS)method was built to determine icarside,hyperoside and psoralen in food.The samples were extracted with 70%methanol,the solid and semi-solid hotpot seasoning samples were purified by solid phase extraction column,and then determined by HPLC-MS/MS.Acetonitrile and 0.1%formic acid solution were used as the mobile phase,and the gradient elution was adopted for analysis.As shown in the results,the analytes had good linearity in the range of 0.05−100 ng/mL,and the correlation coeffificients(R^(2))were greater than 0.999.In this method,the limits of quantitation(LOQ)of psoralen,icariside and hyperoside in liquid samples were 1.25,25.0 and 12.5μg/L respectively;while the LOQs of psoralen,icariside and hyperoside in solid samples and hotpot seasoning samples were 1.25,25.0 and 12.5μg/kg,respectively.The liquid beverage,solid beverage,health food(in the form of oral liquid,capsule,tablet),integrated alcoholic beverage and solid hotpot seasoning were selected as representative samples and used for method validation.The average spiked recoveries at 3 levels(LOQ,2 LOQ,10 LOQ)were in the range of 83.7%−115.0%,and the relative standard deviations were in range of 0.5%−9.4%(n=6).The method is rapid,accurate and sensitive,which is suitable for the simultaneous determination of icariside,hyperoside and psoralen in different food matrices.
基金granted by the National Key R&D Program of China (2021YFD21001005)National Natural Science Foundation of China (31972102,32101980)+1 种基金Special key project of Chongqing technology innovation and application development (cstc2021jscx-cylhX0014)Chongqing Technology Innovation and Application Development Special Project (cstc2021jscx-tpyzxX0014)。
文摘This study aimed to characterize and identify calcium-chelating peptides from rabbit bone collagen and explore the underlying chelating mechanism.Collagen peptides and calcium were extracted from rabbit bone by instant ejection steam explosion(ICSE)combined with enzymatic hydrolysis,followed by chelation reaction to prepare rabbit bone peptide-calcium chelate(RBCP-Ca).The chelating sites were further analyzed by liquid chromatography-tandem mass(LC-MS/MS)spectrometry while the chelating mechanism and binding modes were investigated.The structural characterization revealed that RBCP successfully chelated with calcium ions.Furthermore,LC-MS/MS analysis indicated that the binding sites included both acidic amino acids(Asp and Glu)and basic amino acids(Lys and Arg),Interestingly,three binding modes,namely Inter-Linking,Loop-Linking and Mono-Linking were for the first time found,while Inter-Linking mode accounted for the highest proportion(75.1%),suggesting that chelation of calcium ions frequently occurred between two peptides.Overall,this study provides a theoretical basis for the elucidation of chelation mechanism of calcium-chelating peptides.
基金This study was reviewed and approved by the Maternal and child health hospital of Hubei Province(Approval No.20201025).
文摘BACKGROUND As a well-known fact to the public,gestational diabetes mellitus(GDM)could bring serious risks for both pregnant women and infants.During this important investigation into the linkage between GDM patients and their altered expression in the serum,proteomics techniques were deployed to detect the differentially expressed proteins(DEPs)of in the serum of GDM patients to further explore its pathogenesis,and find out possible biomarkers to forecast GDM occurrence.METHODS Subjects were divided into GDM and normal control groups according to the IADPSG diagnostic criteria.Serum samples were randomly selected from four cases in each group at 24-28 wk of gestation,and the blood samples were identified by applying iTRAQ technology combined with liquid chromatography-tandem mass spectrometry.Key proteins and signaling pathways associated with GDM were identified by bioinformatics analysis,and the expression of key proteins in serum from 12 wk to 16 wk of gestation was further verified using enzyme-linked immunosorbent assay (ELISA).RESULTS Forty-seven proteins were significantly differentially expressed by analyzing the serum samples between the GDMgravidas as well as the healthy ones. Among them, 31 proteins were found to be upregulated notably and the rest16 proteins were downregulated remarkably. Bioinformatic data report revealed abnormal expression of proteinsassociated with lipid metabolism, coagulation cascade activation, complement system and inflammatory responsein the GDM group. ELISA results showed that the contents of RBP4, as well as ANGPTL8, increased in the serumof GDM gravidas compared with the healthy ones, and this change was found to initiate from 12 wk to 16 wk ofgestation.CONCLUSION GDM symptoms may involve abnormalities in lipid metabolism, coagulation cascade activation, complementsystem and inflammatory response. RBP4 and ANGPTL8 are expected to be early predictors of GDM.
基金Supported by Tongren Science and Technology Planning Project (TSKY[2022]42)Education Science Planning Project of Department of Education of Guizhou Province (2023B111).
文摘[Objectives]This study was conducted to explore the occurrence levels of endocrine disruptors(EDCs)in rural areas around a county landfill in Tongren City.[Methods]The water around the landfill was sampled and analyzed.A solid-phase extraction and high performance liquid chromatography-tandem mass spectrometry(SPE-UPLC-MS/MS)method was established for the determination of 27 EDCs.After the HLB solid-phase extraction column was activated,a water sample,which was adjusted with phosphoric acid to a pH of 2(±0.5)and added with 500 mg of disodium EDTA,was loaded,and 5 ml of water and 20%methanol water was added for washing.Next,10 ml of elution solution was added for elution,and the collected eluate was evaporated under reduced pressure at 40℃to near dryness,and 1 ml of reconstitution solution was added to a constant volume.An ACQUITY UPLC BEH C18(100×2.1 mm,2.6μm)chromatographic column was adopted for LC separation by gradient elution with pure water solution-acetonitrile as the mobile phase.For MS detection,the MRM mode was adopted for collection,and the positive and negative ion modes were switched for simultaneous determination,and the internal standard method was used for quantification.[Results]The correlation coefficient R2 was greater than 0.99 in the linear range of each target substance.The limits of quantitation in the method were between 0.05 and 2.00 ng/L,and the recoveries ranged from 75.3%to 105.7%.[Conclusions]The method has high sensitivity,good accuracy and strong practical value.
基金financial support from the National Natural Science Foundation of China (Nos.91843301 and 91543202)National Key Research and Development Program Cooperation on Scientific and Technological Innovation in Hong Kong,Macao and Taiwan (No. 2017YFE0191000)。
文摘Research on pollution characteristics and toxicities of emerging polycyclic aromatic sulfur heterocycles(PASHs) in PM_(2.5) has not been reported due to the lack of analytical method with the needed performance.In the present study,a novel method for the determination of 14 PASHs in PM_(2.5) was developed using atmospheric pressure gas chro matography-tandem mass spectrometry(APGC-MS/MS).Atmospheric pressure chemical ionization was operated with multiple reaction monitoring in positive ionization mode.High sensitivity(method detection limit <1.673 pg/m^(3)),acceptable re coveries(67.6%-120.8%) and precisions(RSD of 2.2%-15.4%) were obtained.The method was successfully applied for analyzing PASHs in 10 PM_(2.5) samples collected from Taiyuan,a typical industrial city in China,in 2016,The total concentrations were from 929 pg/m^(3) to 14,593 pg/m^(3).The determined levels indicated that further investigations on environmental fate and toxicities of PM_(2.5)-bound PASHs may be needed.
基金This work was supported by National Key Research and Development Program of China(2019YFC1606400)Hebei Province High-level Talent Funding Program(A201901008)Research Project of Hebei Administration for Market Regulation(2020ZD12).
文摘A liquid chromatography-tandem mass spectrometry method was established for the determination of ingredients of chicken,duck,pork,beef and mutton.A total of 19 characteristic peptides were screened out from 5 kinds of meat,and a liquid chromatography-tandem mass spectrometry method was established for the determination of characteristic peptides.The accuracy of the method was tested by adding duck,pork and chicken with the mass fractions of 0.5%,1%and 5%to mutton,pork and chicken with the mass fractions of 0.5%,1%and 5%to beef,and duck with the mass fractions of 1%,2%and 10%to beef.The results show that the method has high accuracy and stability,and could be used to determine the content of 3 kinds of adulterated meat components in mutton and beef samples.
基金supported by the Central Public-Interest Scientific Institution Basal Research Fund,CAFS(No.2020TD71).
文摘A precise and reliable analytical method of high performance liquid chromatography-tandem mass spectrometry(HPLCMS/MS)was developed to measure trace levels of enrofloxacin(ENR)and its major metabolite ciprofloxacin(CIP)in carp tissues.Optimized chromatographic separation was obtained on a Waters Xterra MS C_(18) reversed-phase column using gradient elution with methanol and 0.1%formic acid aqueous solution including 5mmolL^(-1) of ammonium acetate.The established method was applied to study the pharmacokinetics and distribution of ENR and CIP in tissues of carp following a single oral administration in feed at a dosage of 40mgkg^(-1) bw(body weight).Data were analyzed using DAS 2.0 dynamics software,and the experimental results suggest that ENR was rapidly absorbed and extensively distributed in carp tissues through systemic circulation,and the pharmacokinetic characteristics can be described with a two-compartment model.The elimination half-lives(t_(1/2β))from muscle,liver,gill,plasma and skin were 131,160,104,132 and 310 h,respectively.The areas under the drug concentration-time curves(AUC)for these tissues were 491,972,750,249 and 706hmgkg^(-1),respectively.The maximum concentration(C_(max))values were 13,29,37,9 and 5mgkg^(-1) with peak times(t_(max))of 8,4,4,2 and 4 h,respectively.Ciprofloxacin,the active metabolite of ENR,was also detected in carp tissues,indicating that only 1.54%of de-ethylation of ENR occurs in carp.At a water temperature of 18℃,the drug withdrawal time was determined to be no less than 24 d while the carp was fed at a single dosage of 40mgkg^(-1).
基金funded by the Forestry Science and Technology Innovation Project of Guangdong Province,China(2020KJCX010).
文摘This study aimed to explore the anti-bacterial and anti-fungal activities of extracts from different parts of plants in the Zingiberaceae family.The inhibitory rate,minimum inhibitory concentration(MIC),and minimum bactericidal concentration(MBC)of leaf and stem,and root and rhizome extracts from Alpinia katsumadai Hayata,Alpinia oxyphylla Miq×Alpinia henryi K.Schumann,Alpinia oblongifolia Hayata,Alpinia nigra(Gaertn.)Burtt,Amomum villosum Lour,Alpinia zerumbet(Pers.)Burtt.et Smith and Alpinia oxyphylla Miq were determined using the fungus cake method and double dilution method.The seven Zingiberaceae plants exhibited characteristic antibacterial activities against pathogenic bacteria and fungi.At a 1.5 mg mL^(−1),A.zerumbet root and rhizome extracts exhibited strong inhibitory activity against S.aureus and E.coli,with 83.23%and 79.62%,respectively.In addition,A.zerumbet leaf and stem extracts had an inhibitory rate of 90.85%against P.aeruginosa.At the same concentration,the leaf and stem,root and rhizome extracts of A.katsumadai had the best anti-bacterial effect against F.oxysporum,with inhibition rates of 84.46%and 84.73%,respectively.Moreover,A.katsumadai and A.zerumbet leaf and stem extracts had the most significant antibacterial effect against S.aureus,with a MIC of 0.063 mg mL^(−1).Thus,both A.katsumadai and A.zerumbet extracts had significant antibacterial activity.In addition,by comparing the inhibitory effect of extracts from different parts,it was found that the inhibitory rate and average inhibitory rate of extracts from leaf and stem were higher than those from root and rhizome.The chemical constituents of A.katsumadai and A.zerumbet,determined by the high-performance liquid chromatography-tandem mass spectrometry(UPLC-MS/MS),revealed that citric acid(CA),alpinetin,and pinocembrin(PNCB)were the functional constituents yielding the antibacterial activity.Overall,A.katsumadai and A.zerumbet have the potential to be developed as new plant fungicides and bactericides.
