UPLC-MS/MS Method for Detection of Etomidate and Its Metabolite Etomidate Acid Quantity in Blood / 法医学杂志

OBJECTIVES@#To establish a method for the simultaneous quantitative analysis of etomidate and its metabolite etomidate acid in blood, and to discuss its application value in actual cases.@*METHODS@#Acetonitrile precipitate protein method was used, and C18 column was selected. Gradient elution was performed with acetonitrile and 5 mmol/L ammonium acetate within 6 min. Electrospray ionization source in positive ion mode was used. The internal standard etomidate acid-d5 was obtained by etomidate-d5 alkaline hydrolysis reaction. Ultra-high performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) was used for quantitative analysis. The methodological verification was conducted.@*RESULTS@#Etomidate and etomidate acid in blood showed good linear relationship in the quantitative linear range (r>0.999), with the lower limit of quantification was 2.5 ng/mL and 7.5 ng/mL, respectively. The accuracy, precision, recovery rate, and matrix effect of the method met the professional verification standards. The practical application results showed that etomidate and etomidate acid could be detected in the blood of the abusers, and their mass concentrations ranged from 17.24 to 379.93 ng/mL.@*CONCLUSIONS@#The method established in this study can simultaneously quantify etomidate and etomidate acid in blood, which is simple and convenient to operate with accuracy. It can meet the detection needs of actual cases and provide technical support for law enforcement to crack down on etomidate abuse.

Rapid Determination of Bucinnazine in Blood by UPLC-MS/MS / 法医学杂志

OBJECTIVES@#To establish a rapid method for the analysis of bucinnazine in blood by UPLC-MS/MS and to apply the method to the practical case.@*METHODS@#After the internal standard was added to blood, the protein was precipitated with 900 μL mixed solution (Vacetonitrile∶Vwater=8∶2). After vortex and centrifugation, the protein was measured through 0.22 μm filter membrane. The separation was performed on C18 chromatography column, with acetonitrile and 5 mmol/L ammonium acetate containing 0.1% formic acid aqueous as mobile phase gradient elution at the flow rate of 0.4 mL/min. Multiple reaction monitoring scan was performed in electrospray positive ion mode, quantitative measurement was performed by internal standard method, and methodological verification was carried out.@*RESULTS@#The linear relationship of bucinnazine in blood was good in the range of 0.5-200 μg/L, the correlation coefficient (r) was 0.999 7, the limit of detection was 0.1 μg/L, the limit of quantitation was 0.5 μg/L, and the recovery was 78.3%-83.8% at 1, 10 and 100 μg/L mass concentration levels. The matrix effect was 69.4%-73.8%, the intra-day precision was 1.9%-2.8%, and the inter-day precision was 2.8%-3.2%, the accuracy was 3.1%-3.5%. The stability test results of 1 and 100 μg/L mass concentrations at -25 ℃ showed that the accuracy (bias) of 10 d was less than 4.5%.@*CONCLUSIONS@#This method has the advantages of simple pre-treatment process, fast sample processing speed, high sensitivity of instrument analysis, good stability of content determination and reliable identification results, and can meet the needs of case identification.

Simultaneous determination of 15 bile acids in Tongren niuhuang qingxin pills by UPLC-MS/MS / 中国药房

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.

Simultaneous determination of 18 common disinfection by-product residues in drinking water by high performance liquid chromatography-tandem mass spectrometry / 上海预防医学

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.

Rapid determination of four herbicides in urine with ultra-high performance liquid chromatography-triple quadrupole tandem mass spectrometry / 预防医学

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.

Forensic Analysis of 9 Poisoning Death Cases Caused by Oral Administration of Diphenidol / 法医学杂志

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.

Determination of Three Types of New Psychoactive Tryptamines in Blood by QuEChERS Combined with UPLC-MS/MS / 法医学杂志

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.

Establishment of a blood concentration detection system for everolimus in recipients after liver transplantation / 器官移植

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.

Study on distribution of succinylcholine chloride at poisoning dose in rats by UHPLC-MS/MS analysis / 中国药理学通报

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.

Qualitative screening of 169 veterinary drug residues in bearbile powder by QuEChERS-ultra high performance liquid chromatography-tandem mass spectrometry / 药学学报

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.

Simultaneous determination of 15 mycotoxins in peanuts by ultra high performance liquid chromatography-tandem mass spectrometry with QuEChERS EMR-Lipid approach and stable isotope dilution / 上海预防医学

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.

Effect of Polyethylene Glycol 400 on Bile Excretion of Baicalin and Its Main Metabolite / 中国实验方剂学杂志

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.

Establishment and Its Application of UPLC-MS/MS Method for 20 Fentanyl-related Substances in Blood / 法医学杂志

Objective To establish an ultra-high performance liquid chromatography-tandem mass spectrometry （UPLC-MS/MS） rapid determination method for simultaneous analysis of 20 fentanyl-related substances in blood. Methods With fentanyl-D5 as an internal standard, the blood was extracted by liquid-liquid extraction （LLE）, then separated with an ACQUITY UPLC HSS T3 chromatographic column, and finally 20 fentanyl-related substances were simultaneously analyzed with multiple reaction monitoring （MRM） mode. Results The limits of detection （LOD） of all compounds were 0.02-0.03 ng/mL, and the limits of quantitation （LOQ） were 0.05-0.2 ng/mL. Within the mass concentration range of 0.05-40 ng/mL, 20 fentanyl-related substances had a good linear relationship, and correlation coefficients were larger than 0.99. The accuracy of the method was 87.69%-114.68% and the extraction recovery rate was 85.35%-101.80%, and no significant matrix effect was observed. The established method was successfully applied to the detection of sufentanil in rat blood after sufentanil was injected. Sufentanil could still be detected in blood of rats 10 h after sufentanil injection. Conclusion The established method has the advantages of simple pretreatment, high sensitivity and good selectivity, and can be used for the determination of fentanyl-related substances in forensic toxicology analysis.

Determination of chlorate and perchlorate in eggs by ultra performance liquid chromatography-tandem mass spectrometry / 国际药学研究杂志

Objective: To establish a method for the determination of chlorate and perchlorate in eggs by ultra high performance liquid chromatography-tandem mass spectrometry(UPLC-MS/MS). Methods: After homogenizing, the egg samples were extracted with 0.1% formate water-acetonitrile,purified by PRIME HLB column,and separated by Thermo Acclaim™ Trinity™ P1 ion exchange column. Eluates from the HPLC system were introduced into Waters Xevo TQ-XS triple quadrupole UPLC-MS/MS system in negative electrospray ionization mode using multiple reaction monitor- ing(MRM),with chlorate18O3 and perchlorate18O4 as internal standard. Results: The chlorate had a good linear rela- tionship in the range of 0.2-100.0 μg/L,with R>0.999. Perchlorate had a good linear relationship in the range of 0.1-50.0 μg/L,with R>0.999. The average recovery of chlorate was 95.7-109.4%,and the precision was 3.0-9.1%. The average recovery of perchlorate was 95.6%-115.3%,and the precision was 2.1%-8.6%. Conclusion: The estab- lished method appears to be simple,rapid,accurate,sensitive,and suitable for the determination of chlorate and per- chlorate in high protein samples.

N-Ethylation facilitates simultaneous quantification of amino neurotransmitters using UHPLC-MS/MS / 上海交通大学学报（医学版）

Objective • To investigate the effect of content changes of neurotransmitters on multiple physiological and pathophysiological processes in mammals, and explore simultaneous sensitive quantification of these metabolites. Methods • An efficient and sensitive method for simultaneous quantification of 20 amino neurotransmitters was achieved through pre-column N-ethylation of neurotransmitters with acetaldehyde and NaBH3CN followed with quantitative analysis using ultra-high performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS). And NaBH3CN and NaBD3CN were used as a pair of stable isotope labeling reagents together with natural isotopic standards to achieve accurate quantification. Results • The analysis showed all 20 neurotransmitters had excellent linearity with R2 over 0.991 0 and sensitivity with the limits of detection (LOD) in the range of 0.5-10 fmol except for histidine with an LOD of 36.5 fmol. The result also showed good robustness with the interday and intraday RSD (relative standard deviation) below 15%. The method was further applied to human urine, serum and saliva samples for validation, in which 14, 10 and 8 neurotransmitters were detected, respectively. Conclusion • The method is of high sensitivity and precision. Compared to previous ones, this method is of great applicability in different matrices, with mild reaction and straightforward procedures. Besides, the reaction reagents are easy to be removed by simple quenching thus avoiding interference in the subsequent analysis.

Determination of ginkgolic acids in Yinxing Tongzhi Dropping Pills by mix-mode SPE-UHPLC/MS/MS / 药学学报

An analytical method was developed for determination of ginkgolic acids in Yinxing Tongzhi Dropping Pills by ultra high performance liquid chromatography-triple quadrupole mass spectrometry. The samples were purified by mix-mode anion exchange and reversed-phase SPE. A chromatographic column, Waters Cortecs T3 (50 mm×2.1 mm, 2.7 μm), was used with acetonitrile-methanol-1% acetic acid (44:44:12) as the mobile phase. The ginkgolic acids were detected by electrospray ionization mass spectrometry in negative mode with multiple reaction monitoring (MRM) mode. Ginkgolic acid C13:0, C15:1 and C17:1 possessed good linear correlation in the mass concentration range from 0.2 to 200 μg·L-1, 2 to 200 μg·L-1, 4 to 200 μg·L-1, respectively, with the correlation coefficients more than 0.999. The mean recoveries at spiked levels of 50, 250 and 600 μg·kg-1 were in the range of 70.8%-95.1%, and the RSDs were 0.7%-8.6%. The limits of quantification were 1, 10, 20 μg·kg-1, respectively. The method could be applied to the analysis of ginkgolic acids in complex matrix samples.

A Fast Analytical Approach for Determination of 16 Kinds of Mycotoxins in Vegetable Oils Using Stable Isotope Dilution and Ultra High Performance Liquid Chromatography-Tandem Mass Spectrometry / 分析化学

A fast, simple and cost-effective UPLC-MS / MS method was established for determination of 16 kinds of mycotoxins in vegetable oils with stable isotope dilution technique. Samples were extracted by acetonitrile-water-acetic acid 84: 15: 1(V/ V) and then diluted using water without any further clean-up steps. The mycotoxins were fully separated on a pentafluorophenyl column. Matrix effects were efficiently compensated by the [ 13 C]-labelled internal standards. The mean recoveries at three different concentration levels ranged from 74. 2％ to 105. 6％ , with RSD varied from 0. 3％ to 13. 9％ . Finally, the method was applied to analyze several kinds of vegetable oil samples. The method was simple, rapid, high sensitive and suitable for the determination of mycotoxins in vegetable oils.

Development of Mass Spectrum Fingerprint Extraction Technology for Antibiotics in Surface Water / 分析化学

An extract method for the fingerprint feature of 49 kinds of antibiotics belonging to multiple classes in surface water was developed.Water sample was purified and concentrated by tandem dual column (MAX and HLB),and qualitatively and quantitatively analyzed by ultra-high performance liquid chromatography-tandem mass spectrometric (SPE-UPLC-MS/MS) under multiple reaction monitoring (MRM) mode.The pretreatment was optimized in types of SPE column,loading pH,eluent and redissolution for multiclass antibiotics.The results showed that the linearity of target antibiotics was good in the range of 0.001-0.5 μg/mL (0.01-5 μg/mL for streptomycin).The recoveries were from 51.7% to 94.8%,and the relative standard deviations (RSDs) ranged from 2.19% to 9.67%.The limits of detection(LOD,S/N=3) were 0.01-3.23 μg/L and 0.05-3.43 μg/L and the limits of quantification (LOQ,S/N=10) were 0.04-10.8 μg/L and 0.17-11.4 μg/L in different redissolve solutions.This method was applied to the determination of antibiotics in water samples from 9 sites of Qinhuai River and Xuanwu Lake.

Determination of Three Kinds of Cannabinoids in Cannabis UsingUltra-high Performance Liquid Chromatography-Tandem MassSpectrometry and Analysis of Phenotype of Cannabis / 分析化学

An analytical method of ultra-high performance liquid chromatography-tandem mass spectrometry (UPLC/PDA-QDa) for the qualitative and quantitative analysis of Δ9-tetrahydrocannabinol (Δ9-THC), cannabidiol (CBD), and cannabinol (CBN) in confiscated cannabis was developed.The seized cannabis was extracted in methanol by sonication.The binary mobile phase consisted of methanol (containing 0.1% formic acid) and water.After centrifugation, the supernatant was separated on Waters UPLC BEH C18 column (50 mm×2.1 mm, 1.7 μm) with isocratic elution at a flow rate of 0.2 mL/min.The three cannabinoids were analyzed by photodiode array (PDA) detector at 220 nm and confirmed by mass spectrometer QDa.The correlation coefficient of standard curve for the three cannabinoids in linearity range was not less than 0.999, as well as the recoveries were 82%-102% with the relative standard deviations (RSD) of 0.36%-4.12% at three spiked levels.The method is specific, easy, quick and suitable for confirmation of the cannabinoids in seized cannabis.Cannabis plants in different areas were classified by their chemical phenotype as drug-type or fiber-type plants, taking into account the phenotypic index Δ9-THC, (Δ9-THC+CBN)/CBD, or the Δ9-THC/CBD and the (Δ9-THC+CBN)/CBD ratios.The analysis of the original composition of plant material is necessary for the detection and the quality control of cannabis plants.

Determination of 38 Kinds of Pesticide Residues in Nuts by QuEChERS-Ultra Performance Liquid Chromatography-Tandem Mass Spectrometry / 分析化学

A multi-residue analysis method was developed for the determination of 38 kinds of pesticides in nuts (almonds, peanuts, cashew nuts and walnuts) by QuEChERS-ultra-high performance liquid chromatography-tandem mass spectrometry.The pesticide residues were extracted with acetonitrile.The extract was cleaned up with PSA, C18 and Oasis PRiME HLB, and then analyzed by UPLC-MS/MS with multiple reaction monitoring (MRM) mode.External standard method was employed to quantify.The limits of detection (LODs, S/N=3) of this method were between 0.01 and 10 μg/kg, and the limits of quantitation (LOQs, S/N=10) were between 0.05-20 μg/kg.All of the tested pesticides showed good linear relationship (r>0.991).The practical samples were determined at three spiked levels and the average recoveries were between 51.0% and 126.0%.The RSDs were less than 20%.This method was simple, sensitive and accurate, and could be used for the routine analysis of pesticide residues in nuts.