Determination of Veterinary Drug Residues in Animal-derived Foods by Liquid Chromatography-Mass Spectrometry

[Objectives]This study was conducted to establish a rapid and effective method for simultaneous extraction of 54 kinds of veterinary drug residues in animal-derived food, including sulfonamides, quinolones, tetracyclines, malachite greens, penicillins, nitroimidazoles, tranquilizers and macrolides, by HPLC-MS. [Methods] The samples were extracted with 80% acetonitrile water(containing 0.1% formic acid), combined with QuEChERS extraction technology and C18 and PSA purification, analyzed by high performance liquid chromatography-mass spectrometry, and quantified by external standard method. The target substances were analyzed on ZORBAX Eclipse C18 chromatographic column using 0.2% formic acid water and 0.2% methanol as mobile phases. The gradient elution mode was used for chromatographic separation and multiple reaction detection. [Results] In the linear range of 0.5-50.0 ng/ml, the linear relationship of the 54 kinds of veterinary drug residues was good, with correlation coefficients(r~2) greater than 0.995, and the detection limits ranged from 0.30 to 1.00 μg/kg. The results showed that the recovery ranged from 75.4% to 118.2% when different matrixes were added for recovery. [Conclusions] This method is simple, efficient, accurate, stable, and highly operable. It is applicable to simultaneous batch screening of veterinary drug residues in animal-derived food, and has high practical application value.

Chemical Components of Achyranthes bidentata Leaves by Ultra High Performance Liquid Chromatography-Mass Spectrometry

[Objectives] To study the chemical components and relative content of Achyranthes bidentata leaves and provide a scientific basis for further development and utilization of A. bidentata leaves.[Methods] The chemical components of A. bidentata leaves were rapidly analyzed using the ultra high performance liquid chromatography-time of flight-high resolution mass spectrometry (UHPLC-TOF-MS).[Results] Thirty eight chemical compounds were identified in samples of A. bidentata leaves collected from Wen County of Henan Province, in which seven chemical compounds had the relative content higher than 5%, linoleic acid reached 25.7% and inokosterone A reached 13.8%.[Conclusions] A. bidentata leaves contain many kinds of chemical compounds. This study is expected to provide a certain basis for further extraction of linoleic acid and inokosterone A.

A Validated Liquid Chromatography-Mass Spectrometry Method for the Detection and Quantification of Oxidative Metabolites of 2,2',4,4'-Tetrabromodiphenyl Ether in Rat Hepatic Microsomes

In the present study, we developed and validated an analytical method using ultra performance liquid chromatography-mass spectrometry (UPLC/MS) for the quantitative determination of 2,2',4,4'-tetrabromodiphenyl ether (BDE-47) metabolism by rat hepatic microsomes. BDE-47 is a brominated flame retardant that was widely used in a variety of consumer products and has subsequently been identified as a ubiquitous environmental contaminant. Hydroxy-bromodiphenyl ethers (OH-BDEs) were isolated from rat hepatic microsomes by liquid-liquid extraction. Chromatographic separation was achieved by UPLC on a C18 column with gradient elution using a mobile phase consisting of methanol and water, each containing 0.1% formic acid, at a flow rate of 0.2 mL/min. Detection and quantification were performed using a mass spectrometer in single ion recording mode with negative electrospray ionization. The UPLC/MS method was validated for linearity, limit of quantification (LOQ), accuracy, precision and recovery. The weighted calibration curves (1/X2) were linear over a concentration range of 5 - 250 nM with LOQ values between 5 nM and 50 nM for the individual OH-BDEs. Intra- and inter- day accuracy (%DEV) and precision (%RSD) values ranged from –11.7% to 9.5% and 5.9% to 16.5%, respectively. Recovery values of 70% to 90% were obtained for all OH-BDEs. The validated method allowed us to successfully analyze metabolite formation following incubation of BDE-47 with hepatic microsomes prepared from phenobarbital-treated rats. Results demonstrate that the UPLC/MS method has sufficient sensitivity and reproducibility to fully characterize the in vitro metabolism of BDE-47 and possibly other PBDEs.

CO₂Absorption Solvent Degradation Compound Identification Using Liquid Chromatography-Mass Spectrometry Quadrapole-Time of Flight (LCMSQTOF)

The degradation of the alkanolamine solvent used in the removal of acid gases from natural gas streams due to exposure to contaminants, thermal degradation and presence of oxygen or oxygen containing compounds will change the solvent properties, such as heat transfer coefficient, diffusion coefficient, and mass transfer coefficient of the solvent. Therefore, characterization and quantification of amine degradation product becomes one of the important analyses to determine alkanolamine solvent’s health. In order to identify degradation products of alkanolamine solvent, analytical strategies by using mass spectrometry (MS) as detector have been studied extensively. In this work, due to the low concentration of the amine degradation product, a method was developed for identification of alkanolamine degradation products using LCMS-QTOF technique. A strategy for identification of trace degradation products has been identified. Six (6) alkanolamine degradation products had been identified by using LCMS-QTOF targeted analysis in the blended alkanolamine solvent used in natural gas processing plant. Another fifteen (15) molecular formulas having similarity in chemical structure to alkanolamine degradation products were identified using untargeted analysis strategy, as possible compounds related to degradation products. Using LCMS-QTOF via targeted and untargeted analysis strategy, without tedious column separation and reference standard, enables laboratory to provide a quick and indicative information for alkanolamine solvent’s organic degradation compounds identification in CO2 adsorption, within reasonable analysis time.

Liquid Chromatography-mass Spectrometry Analysis on Effect of Roughage Types on Liver Metabolic in Dairy Cows

The major objective of this study was to determine the effect of corn straw or mixed diet on the small molecule metabolites of liver and milk production of healthy Chinese Holstein cows during lactation.In this study,metabolomic methods based on ultra performance liquid chromatography-mass spectrometry(LC-MS)were used to study the liver metabolites of dairy cows fed on corn straw diet or mixed diet.Ten healthy Chinese Holstein cows were randomly assigned to two groups,under the same management condition,fed different diets respectively,corn straw group(CS)or a mixture of alfalfa hay and Chinese wild rye hay mixed forage group(MF).All the cows were fed for 8 weeks and recorded body weight,dry matter intake,body condition score,fat,protein,lactose,milk yield and the total solids.Livers were sampled from each cow through a liver puncture needle for analysis of a significant difference in small molecule metabolites in cow liver samples from the two different diets.The results suggested that different diet types had significant effects on liver metabolism and milk components in dairy cows.The contents of milk fat,the total solids,milk protein,lactose,dry matter intake(DMI),milk yield,milk protein(%),lactose(%)and milk fat(%)of the corn straw group were significantly lower than those of the mixed forage group(p<0.05);the contents of phosphatidylcholine(PC),histidine,hypoxanthine and mridine in liver tissues of the corn straw group were significantly lower than those in the mixed forage group(p<0.05);acetylcarnitine,uric acid,triacylglycerol(TG),acetal phosphatidylcholine(plasmenyl-PC),acetalphosphatidylethanolamine(plasmenyl-PE)and sphingomyelin(SM)of the corn straw group were significantly higher than those in the mixed forage group(p<0.05).In summary,cows fed on mixed forage diet significantly improved milk yield and lactation performance clearly.

Novelties Filtration Theory of Liquid Chromatography-Mass Spectrometry in Volume Nanotube of Cotton Filament of Layers Woven Fabrics

Objectives of the research to present a modern theory of water purification for multiple purposes entitled “a novelties filtration theory of liquid chromatography-mass spectrometry” is an exceedingly sensitive and specific analytical technique in volume layers woven fabrics that can precisely determine the identities and quantities of compounds within volume Nanotube of cotton filament of layers woven fabrics. The problems are that the filters in the local and international markets have increased complications in configuration, installation and cost without reaching the efficiency that humanity hopes. Throw materials and methods the chromatography-mass spectrometry in layers woven fabrics, and throw the nanotube of cotton filament for purification of water dyes and smells. Industry, in which mass spectrometry is a convenient, versatile method for characterization and identification of process throw the Nanotube of cotton filament for purification of water dyes and smells. Results came up with a theme “innovations in textiles”, and also, for characterization of fibers and contaminants of the fabrics. Additive manufacturing in layers woven fabrics, are the processes used to synthesize a volume object under computer control with successive material layers that have been used and highlighted. The conclusions has included chromatography-mass spectrometry drop, physico-chemical, biological, combined physical-biological and chemical-biological treatment processes recently being developed to meet Jet-filtration, the strict discharging limits set by ASTM standards. Some important aspects of both qualitative and quantitative data analysis have been described and the power of using mass profiles to enhance selectivity and sensitivity has been demonstrated.

Determination of penehyclidine hydrochloride in beagle dog plasma by liquid chromatography-electrospray ionization mass spectrometry and the pharmacokinetic study

To develop a fast and sensitive liquid chromatography-mass spectrometry method for the determination of penehyclidine hydrochloride （PH） in beagle dog plasma. PH and diphenhydramine hydrochloride （internal standard, IS） were extracted with a solvent mixture of petroleum ether-ethyl ether （7：3）. Chromatographic separation was achieved on a reversed-phase Eclipse XDB-C18 column （4.6 mm × 150 mm, 5 um） using the eluent of methanol-water （5 mmol/L ammonium acetate） （90：10, v/v, pH 5.8） as mobile phase. The electrospray ionization source was set at the positive multiple reaction monitoring （MRM） mode. This method involved the use of the [M＋H]^＋ ions of PH and diphenhydramine hydrochloride at m/z 316.4- 128.2 and m/z 256.4-167.2. The calibration curve was linear in the range of 1-1000 ng/mL with a correlation coefficient of 0.9988. The lower limit of quantification was 0.05 ng/mL. The precision, accuracy and recovery of the method were acceptable. Following intravenous injection admires＇ tration at doses of 0.5, 1 and 5 mg/kg PH, the main pharmacokinetic parameters were as the followings, t1/2a 0.33 h, t1/2β 2.44 1% tmax 0.058 1% AUC and Cmax exhibited a linear increase along with the increase of dose. The two-compartment model fit the three dose groups. This method was sensitive, accurate and fast for the determination of concentration of PH in beagle dog plasma. It could be used in pharmacokinetic studies of PH.

Determination of brominated diphenyl ethers in atmospheric particulate matter using selective pressurized liquid extraction and gas chromatography–mass spectrometry with a negative chemical ionization

This study describes the development and validation of a sensitive and reliable method for determination of polybrominated diphenyl ethers（PBDEs）in atmospheric particulate matter using selective pressurized liquid extraction（SPLE）and gas chromatography–mass spectrometry with a negative chemical ionization（GC-NCI-MS）.Extraction and clean-up were performed using PLE with 2 g florisil and 3 g silica placed in the extraction cells.Under optimal conditions,14 PBDEs were extracted at 70℃ using hexane/dichloromethane（50：50,v/v）as solvent.Validation of SPLE returned excellent recoveries for most analytes,with relative standard deviations mostly below20%.Method detection limits ranged from 0.13 to15.38 ng·mL^-1 for the GC-MS analyses.The method was successfully applied to atmospheric particulate matter of Beijing,where analytes were detected in the range of182.79 to 468.99 pg·m^-3.

Untargeted and targeted mass spectrometry reveal the effects of theanine on the central and peripheral metabolomics of chronic unpredictable mild stress-induced depression in juvenile rats

L-theanine has been shown to have a therapeutic effect on depression.However,whether L-theanine has an excellent preventive effect on depression in children and adolescents and what its mechanism is have not been well explained.Given the complexity of the pathogenesis of depression,this study investigated the preventive effect and mechanism of L-theanine on depression in juvenile rats by combining serum and hippocampal metabolomic strategies.Behavioral tests,hippocampal tissue sections,and serum and hippocampal biochemical indexes were studied,and the results confirmed the preventive effect of Ltheanine.Untargeted reversed-phase liquid chromatography-quadrupole-time-of-flight mass spectrometry and targeted hydrophilic interaction liquid chromatography-triple quadrupole mass spectrometry were developed to analyze the metabolism changes in the serum and hippocampus to screen for potential biomarkers related to L-theanine treatment.The results suggested that 28 abnormal metabolites in the serum and hippocampus that were considered as potential biomarkers returned to nearnormal levels after L-theanine administration.These biomarkers were involved in various metabolic pathways,mainly including amino acid metabolism and lipid metabolism.The levels of amino acids and neurotransmitters in the phenylalanine,tryptophan,and glutamic acid pathways were significantly reduced after L-theanine administration compared with chronic unpredictable mild stress-induced rats.In summary,L-theanine had a significant preventive effect on depression and achieved its preventive results on depression by regulating various aspects of the body,such as amino acids,lipids,and inflammation.This research systematically analyzed the mechanism of L-theanine in preventing depression and laid the foundation for applying L-theanine to prevent depression in children and adolescents.

Application of Mass Spectrometry (MS)-coupled Techniques in Pesticide Residue Detection

Pesticide residue detection is an important work to ensure the quality safety of agricultural products.In the process of agricultural production,in order to prevent and control agricultural diseases and pests,a certain amount of pesticides need to be used.However,if pesticides are used excessively,there will be certain pesticide residues in crops and related products.Therefore,it is necessary to do a good job in pesticide residue detection.The gas chromatography-mass spectrometry(GC-MS)and liquid chromatography-mass spectrometry(LC-MS)detection methods have good results and can effectively detect pesticide residues in related products.This paper reviewed and analyzed the application of GC-MS and LC-MS in pesticide residue detection,and proposed optimization measures based on practical experience,hoping to provide reference for relevant scholars.

超高效液相色谱-三重四级杆串联质谱法测定化妆品中达克罗宁和新康唑

利用超高效液相色谱-三重四级杆串联质谱技术,建立化妆品中达克罗宁和新康唑非法添加物定性定量检测方法。样品经饱和氯化钠溶液分散,乙腈提取,超声波冰浴30 min助提。采用C18柱色谱柱(100 mm×2.1 mm,1.9μm),用流动相A(0.1%甲酸水)和流动相B(甲醇)进行梯度洗脱,流量为0.3 mL/min,柱温为30℃,进样体积为2μL。达克罗宁和新康唑的质量浓度在1~100 ng/mL范围内与色谱峰面积线性关系良好,相关系数均大于0.999。当取样质量为0.2 g时,质量分数定量限均为0.1μg/g,检出限均为0.03μg/g。该方法灵敏、快速,可用于化妆品中达克罗宁和新康唑两种目标物的测定。

Characterization of mulberry leaf instant tea and evaluation of its hypolipidemia effect via regulation of intestinal microbiota

The purpose of this study was to characterize mulberry leaf instant tea(MLIT)powder prepared from the'Longsang No.1'(Morus abla L.cv.Longsang 1)mulberry leaves in Heilongjiang Province(China)and assess its obesity-preventing/relieving effects.A total of 174 compounds including quercetin,chlorogenic acid,1-deoxyecomycin(1-DNJ)related to antihyperlipidemia effects were identified from the MLIT powder.MLIT treatment reversed the Lee's index,fat coefficient,and serum biochemical parameters in both the obesity relieving and obesity preventing mice fed with high-fat diet.In the obesity relieving experiment,the relative abundance of Desulfovibrio in mouse feces decreased after both 0.5%and 1%MLIT treatments.In obesity preventing experiments,mouse with different amount of MLIT treatments showed increased relative abundance of Akkermansia,Bifidobacterium and Lactobacillus,while Deferribacteres,Desulfobacterota decreased.The beneficial bacteria in the intestinal tract of mice treated with MLIT increased.This study proved that MLIT had antihyperlipidemia potential via modulating intestinal microbiota in mice.

Analysis of Polymer Impurities in Cephalosporin Antibiotics

[Objectives]To establish a HPLC-MS method for the determination of polymer impurities in cefathiamidine and its preparations.[Methods]Kromasil 100-5 C_(18) column(4.6 mm ×250 mm,5μm)was used for analysis;mobile phase ammonium acetate solution(pH 6.30)-acetonitrile,gradient elution;volumetric flow rate 1.0 mL/min;column temperature 40℃;multi-reaction monitoring mode was used for analysis,and positive ion scanning was chosen as the electrospray ion source.[Results]The resolution between impurities and main peaks under this method was greater than 1.5,and 8 known impurities and 2 polymer impurities could be completely separated and distinguish-ed.It was inferred that the molecular ion peak[M+H]^(+):m/z727.1874,m/z 785.1937 was the possible polymer impurity of this product.[Conclusions]A method for the analysis of polymer impurities in cefathiamidine and its preparations was formed,which could achieve the purpose of simultaneous analysis of small molecule impurities and polymer impurities,and could better control the content of single impurities in the polymer,providing a reliable inspection basis for strict control of cefathiamidine quality.

化学检测技术在食品安全检测中的应用

化学检测技术在食品安全领域扮演着至关重要的角色。通过高效液相色谱、气相色谱、质谱等技术,可以准确检测食品中的残留农药、兽药、添加剂及其他潜在危害物质,为风险评估和监管提供科学依据。随着科技进步,化学检测方法不断发展,提高了检测的准确性、灵敏度和效率。本文综述了化学检测技术在食品安全中的应用情况,分析了各种技术的优势与挑战,并探讨了未来的发展趋势。

基于高效液相色谱-质谱联用的千里光治疗寻常型银屑病网络药理学分析

目的:探究千里光治疗寻常型银屑病的成分-靶点-通路作用机制,为其进一步研究提供依据。方法:使用高效液相色谱-质谱联用技术(HPLC-MS)检测千里光入血成分;在TCMIP数据库中检索千里光入血成分靶点,并在OMIM、DrugBank、GeneCards、TTD数据库中检索寻常型银屑病靶点,绘制Venn图取两者交集靶点;使用String构建交集靶点蛋白-蛋白相互作用网络,使用Cytoscape 3.8.2构建千里光核心入血成分-交集靶点网络,使用Metascape进行基因本体(GO)功能及京都基因与基因组百科全书(KEGG)通路富集分析;使用AutoDockTools1.5.7进行分子对接,并用PyMOL实现可视化。结果:共得到千里光入血成分50个,其中核心入血成分9个。核心入血成分靶点85个,寻常型银屑病靶点1 175个,两者交集靶点18个。蛋白互作网络得到关键靶点HSP90AA1、ESR1、AKT1,千里光核心入血成分-交集靶点网络得到主要成分山柰酚、槲皮素,KEGG富集分析得到PI3K-Akt等关键信号通路,GO富集分析中生物过程主要涉及对激素的反应、对炎症反应的调节、细胞对脂质的反应等,细胞组成主要涉及转录调控复合体、囊泡腔、分泌颗粒腔等,分子功能主要涉及激酶结合、蛋白激酶结合、蛋白激酶活性等。山柰酚、槲皮素与核心靶点AKT1分子对接结合能分别为-6.59 kcal/mol、-6.67 kcal/mol。结论:千里光核心入血成分山柰酚、槲皮素可能通过AKT1靶点,作用于PI3K-Akt信号通路发挥对寻常型银屑病的治疗作用。

苦杏仁抑菌肽的筛选富集及结构鉴定

为探究苦杏仁抑菌肽的制备、富集及结构分析,本实验以苦杏仁为原料,在脱脂后提蛋白,使用酶法制备苦杏仁蛋白抑菌肽,优化制备工艺,检测抑菌肽的抑菌活性,进一步纯化富集,分离出抑菌活性最强的抑菌肽组分并对其进行结构分析。结果表明,木瓜蛋白酶酶解物对于革兰氏阳性菌尤其是金黄色葡萄球菌的抑菌作用最强。优化苦杏仁抑菌肽的制备工艺最佳条件为:酶解温度为74℃,酶底比为2.5%,pH为7。得到抑菌肽的蛋白浓度为19.21%,并测得最低抑菌浓度为3.13 mg/mL。利用超滤和凝胶过滤色谱(Sephadex G-25)对抑菌肽进行分离纯化,从中筛选出肽组分A-II-b对金黄色葡萄球菌的抑制活性最强。将凝胶过滤条件优化为:样品浓度9.38 mg/mL,洗脱速度0.68 mL/min、洗脱剂为纯水。在此条件下测得肽组分A-II-b的峰面积比为13.15%。采用液相色谱-质谱联用技术对肽组分A-II-b进行结构分析,将结果导入Uniprot数据库与APD3数据库进行匹配,筛选出7种分子量在1500~2500 Da的潜在具有抗菌活性的苦杏仁肽序列,分别是ALPDEVLQNAFRIS、ESWNPRDPQFQWAGVA、VAYWSYNNGEQPLVA、FLDLSNDQNQLQLDQVPR、GENDNRNQIIRVR、RNLQGE NDNRNQIIRVR和RALPDEVLQNAFRIS。本研究促进了杏仁活性肽的深度开发和资源再利用,同时也为其作为抑菌肽的研究和进一步开发利用提供理论依据。

液相色谱-串联质谱法前处理技术在食品中硝基咪唑类药物检测中的应用进展

硝基咪唑类药物具有抗菌和抗原虫作用,但由于存在致突变和潜在致癌性,部分药物种类在动物源食品中被禁止使用。在近几年的监测检验中,硝基咪唑类药物残留超标现象时有发生,因此开发快速、高效、准确的硝基咪唑类药物残留检测方法,对于实现对硝基咪唑类药物的高效监管,进而有效确保食品安全具有重要意义。本文对食品中硝基咪唑类药物的液相色谱-串联质谱检测方法中涉及的前处理技术进行了综述,分析了各种前处理方法的特点和优势,并对其发展方向进行展望。

液相色谱-质谱联用技术在食品安全检测中的应用

高效、准确的检测技术是保障食品安全的关键,而液相色谱-质谱联用技术(Liquid Chromatography-Mass Spectrometry,LC-MS)凭借其高灵敏度、高选择性和多靶向分析能力,在复杂基质中痕量目标物的检测方面展现出显著优势,为食品安全质量控制提供了强有力的技术支撑。本文阐述了LC-MS技术的基本原理以及食品安全检测的重要性,并探讨了该技术在农药残留、真菌毒素、食品添加剂和重金属污染物检测等方面的具体应用。

液质联用技术在医药院校药物分析专业实验教学中的应用

液相色谱-质谱联用技术是一门综合性分析技术,在样品分离及结构鉴定中发挥着重要的作用。本文以双黄连口服液主要药效物质分析实验的教学为例,把液质联用技术引入到药物分析专业的本科实验教学中,介绍了方法建立、色谱分离、质谱鉴定和数据分析完整的实验流程,可以增强该专业本科生对前沿研究技术的了解,开拓学生的视野,对于培养该专业学生的科研创新思维、实践能力和问题分析能力起着非常重要的作用,也为培养更多高水平技术人才做准备。

液相色谱-质谱联用技术在肉制品中β-受体激动剂类药物残留检测中的应用

受体激动剂类药物在畜牧业中仍存在非法使用的风险,对消费者健康造成潜在威胁。本文采用液相色谱-质谱联用技术(Liquid Chromatography-Tandem Mass Spectrometry,LC-MS/MS)建立了一种检测猪肉中β-受体激动剂类药物残留的方法。样品经酶解、净化、浓缩后,采用LC-MS/MS在多反应监测(Multiple Reaction Monitoring,MRM)模式下进行定性定量分析。优化后的前处理条件为甲醇-水(70∶30,v/v)作为提取溶剂,37℃β-葡萄糖醛酸苷酶水浴酶解12 h,固相萃取净化。优化后的仪器条件为采用C18色谱柱,0.1%甲酸水溶液和乙腈为流动相,梯度洗脱。4种β-受体激动剂在给定浓度范围内与响应值呈良好的线性关系,相关系数均大于0.99;日内和日间相对标准偏差均小于10%,回收率为87.9%~92.5%,基质效应值在90.4%~109.7%。该方法满足肉制品中β-受体激动剂类药物残留检测的要求。