Rapid Determination of Dopamine and Its Metabolites During in vivo Cerebral Microdialysis by Routine High Performance Liquid Chromatography With Electrochemical Detection

To determine dopamine and its metabolites during in vivo cerebral microdialysis by routine high performance liquid chromatography with electrochemical detection. Methods Microdialysis probes were placed into the right striatum of Wistar rat brains and perfused with Ringer＇s solution at a rate of 1.5 pL/min. A reverse phase HPLC with electrochemistry was used to assay DA, DOPAC, and HVA after cerebral microdialysates were collected every 20 minutes from awake and freely moving rats. In order to identify the reliability of this method, its selectivity, linear range, precision and accuracy were tested and the contents of DA, DOPAC, and HVA in rat microdialysates were determined. Results The standard curve was in good linear at the concentration ranging from 74 nmol/L to 1.5 pmol/L for DOPAC （r^2= 0.9996）, from 66 nmol/L to 1.3 gmol/L for DA （r^2=l.0000） and from 69 nmol/L to 1.4 pmol/L for HVA （r^2=0.9992）. The recovery of DOPAC （0.30, 0.77, 1.49 gmol/L）, DA （0,26, 0.69, 1.32 gmol/L）, and HVA （0.27, 0.71, 1.37 gmol/L） was 82.00±1.70%, 104.00±4.00%, 98.70±3.10%; 92.30± 1.50%, 105.30±2.30%, 108.00±2.00%; 80.00±7.80%, 107.69±8.00%, and 108.66±3.10%, respectively at each concentration. Their intra-day RSD was 3.3%, 3.4%, and 2.5%, and inter-day RSD was 4.2%, 2.3%, and 5.6%, respectively. The mean extracellular concentrations of DOPAC, DA, and HVA in rat brain microdialysates were 10.7, 2.4, and 9.2 gmol/L （n=6）, respectively. Conclusion The findings of our study suggested that the simple, accurate and stable method can be applied to basic researches of diseases related to monoamines neurotransmitters by cerebral microdialysis in rats.

Trace Determination of Tamoxifen in Biological Fluids Using Hollow Fiber Liquid-Phase Microextraction Followed by High-Performance Liquid Chromatography-Ultraviolet Detection

The applicability of hollow fiber liquid-phase microextraction (HF-LPME) combined with high-performance liquid chromatography-ultraviolet detection (HPLC-UV) was evaluated for the extraction and determination of tamoxifen (TAM) in biological fluids including human urine and plasma. The drug was extracted from a 15 mL aqueous sample (source phase;SP) into an organic phase impregnated in the pores of the hollow fiber (membrane phase;MP) followed by the back-extraction into a second aqueous solution (receiving phase;RP) located in the lumen of the hollow fiber. The effects of several factors such as the nature of organic solvent, compositions of SP and RP solutions, extraction time, ionic strength and stirring rate on the extraction efficiency were examined and optimized. An enrichment factor of 360 along with substantial sample clean up was obtained under the optimized conditions. The calibration curve showed linearity in the range of 1 - 500 ng?mL–1 and the limit of detection was found to be 0.5 ng?mL–1 in aqueous medium. A reasonable relative recovery (≥89%) and satisfactory intra-assay (3.7% - 4.2%, n = 3) and inter-assay (7.5% - 7.8%, n = 3) precision illustrated good performance of the analytical procedure in spiked human urine and plasma samples.

Novel method for the determination of five carbamate pesticides in water samples by dispersive liquid-liquid microextraction combined with high performance liquid chromatography

A novel method for the determination of five carbamate pesticides （metolcarb, carbofuran, carbaryl, isoprocard and diethofencard） in water samples was developed by dispersive liquid-liquid microextraction （DLLME） coupled with high performance liquid chromatography-diode array detector （HPLC-DAD）. Some experimental parameters that influence the extraction efficiency were studied and optimized to obtain the best extraction results. Under the optimum conditions for the method, the calibration curve was linear in the concentration range from 5 to 1000 ng mL^-1 for all the five carbamate pesticides, with the correlation coefficients （r^2） varying from 0.9984 to 0.9994. Good enrichment factors were achieved ranging from 80 to 177- fold, depending on the compound. The limits of detection （LODs） （S/N = 3） were ranged from 0.1 to 0.5 ng mL^-1. The method has been successfully applied to the analysis of the pesticide residues in environmental water samples.

A high-performance liquid chromatography with fluorescence detection method for the simultaneous quantitation of monoamine neurotransmitters and their metabolites in subregions of rat brain

Abstract： In the presem study, we simultaneously quantified the levels of monoamine neurotransmitters （MANTs） and their metabolites （levodopa, norepinephrine, epinephrine, dopamine, 5-HT, 3,4-dihydroxyphenylacetic acid, homovanillic acid and 5-hydroxyindole-3-acetic acid） in different brain subregions of rats using a newly developed simple, sensitive and selective high-performance liquid chromatography with fluorescence detection （HPLC-FLD） method. In this new HPLC-FLD method, analytes were directly extracted and separated without deriveatization step within 20 min. The FLD wavelength was set at 280 nm and 330 nm for excitation and emission, respectively. The analytes were separated on an Agilent Eclipse Plus Cls column （4.6 mm×150 mm, 5.0 μm） equipped with an Agilent XDB-C18 security guard column （4.6 mm×12.5 mm, 5.0 lam）, and the column temperature was maintained at 35 ℃. The mobile phase for elution was isocratic. The mobile phase consisted of citric acid buffer （50 mmol/L citric acid, 50 mmol/L sodium acetate, 0.5 mmol/L octane sulfonic acid sodium salt, 0.5 mmol/L Na2EDTA and 5 mmol/L triethylamine, pH 3.8） and methanol （90：10, v/v） at a flow rate of 1.0 mL/min. The detection limit （DL） was 0.9-23 nM for all the MANTs and their metabolites with a sample volume of 50 μL. The method was shown to be highly reproducible in terms of peak area （intraday, 0.08%-1.85% RSD, n = 5）. The simultaneous measurement of these MANTs and their metabolites improved our understanding of the neurochemistry in the central nervous system （CNS） in relation to different addictive drugs （methamphetamine, heroin and their mixture） in drug-addicted rat models.

Imidazolium ionic liquid as the background ultraviolet absorption reagent for determination of morpholinium cations by high performance liquid chromatography-indirect ultraviolet detection

A novel analytical method was developed for determining morpholinium cations lacking ultraviolet absorption groups.This determination was carried out by high performance liquid chromatographyindirect ultraviolet（HPLC-1UV） detection using imidazolium ionic liquid as background absorption reagents,and imidazolium ionic liquid aq.soln.-organic solvent as mobile phase by a reversed-phase C18 column.The background ultraviolet absorption reagents,imidazolium ionic liquids and organic solvents were investigated.The imidazolium ionic liquid in the mobile phase is not only the background ultraviolet absorption reagent for IUV,but also an active component to improve the separation of morpholinium cations.It was found that morpholinium cations could be adequately determined when0.5 mmol/L 1-ethyl-3-methylimidazolium tetrafluoroborate aq.soln./methanol（80：20,v/v） was used as mobile phase with an IUV detection wavelength of 210 nm.In this study,the baseline separation of Nmethyl,ethylmorpholinium cations（MEMo） and N-methyl.propylmorpholinium cations（MPMo） was successfully achieved in 8.5 min.The detection limits（S/N = 3） for MEMo and MPMo were 0.15 and0.29 mg/L,respectively.This simple and practical method has been successfully applied to the determination of two morpholinium ionic liquids synthesized by the chemistry laboratory.

Determination of Amantadine Residue in Honey by Solid-phase Extraction and High-performance Liquid Chromatography with Pre-column Derivatization and Fluorometric Detection

Amantadine （AMA） is an anti-viral drug used in apiculture to protect honeybee against the sacbrood virus （Morator aetatulae）. This study described a reliable high-performance liquid chromatographic （HPLC） method for analyzing AMA in honey using a solid-phase extraction （SPE） cartridge （Plexa PCX） for purification, 4-fluoro-7- nitro-2,1,3-benzoxadiazole （NBD-F） as a pre-column derivatization agent, and fluorometric detection （λex =470 nm, λem=530 nm）. The chromatographic separation was performed on an XDB C18 column （150×4.6 mm i.d.） using 0.1% trifluoroacetic acid/acetonitrile （35 ; 65, V/V） as the mobile phase at a flow rate of 1.0 mLomin 1 with a run time of 20 min. Under these optimal conditions, a linear relationship was observed in the range of 0.025--1.0μg·mL-1 with a good correlation coefficient （0.998） and low limit of detection （0.0080 μg·g-1）, the recoveries were all above 90%, and the intra-day and inter-day precision （RSD） ranged from 3.4%--5.1%.

Separation and identification of moxifloxacin impurities in drug substance by high-performance liquid chromatography coupled with ultraviolet detection and Fourier transform ion cyclotron resonance mass spectrometry

In this paper, a high-performance liquid chromatography coupled with ultraviolet detection and Fourier transform-ion cyclotron resonance mass spectrometry （HPLC-UV/FrICRMS） method was described for the investigation of impurity profile in moxifloxacin （MOX） drug substance and chemical reference substance. Ten impurities were detected by HPLC-UV, while eight impurities were identified by using the high accurate molecular mass combined with multiple-stage mass spectrometric data and fragmentation rules. In addition, to our knowledge, five impurities were founded for the first time in MOX drug substance.

A high-performance liquid chromatography with circular dichroism detector for determination of stereochemistry of 6, 9-oxygen bridge dibenzocyclooctadiene lignans from kadsura coccinea

The stereochemistry of two 6, 9-oxygen bridge dibenzocyclooctadiene lignans from Kadsura coccinea, are difficult to separate and very unstable. The present study was designed to develop a high-performance liquid chromatography using circular dichroism detection for the analysis of the stereochemistry. A new 6, 9-oxygen bridge dibenzocyclooctadiene lignans named Kadsulignan Q was firstly found with an S-biphenyl configuration. The other compound was identified as Kadsulignan L with an R- biphenyl configuration. In order to obtain kinetic data on their reversible interconversion, the stability was measured at different deuterated solvents such as deuterated methanol, deuterated chloroform and deuterated dimethylsulfoxide. The lignans were more unstable and converted more easily in deuterated methanol than in deuterated chloroform and deuterated dimethylsulfoxide.

High performance liquid chromatography for the determination of flavonoids

Due to their biological and physiological importance,flavonoids receive considerable attention in the literature. Nowadays,high performance liquid chromatography（HPLC）is the most widely used analytical method.In this review,we summarize the principle of the choice of HPLC column and mobile phase,discuss and compare the features of various detections such as UV,fluorescence detection,electrochemical detection,chemilummescence detection,UV-MS etc.Recent developments in HPLC including ultra-LC and miniaturization of LC（micro-LC,capillary-LC,and nano-LC）,are also discussed.

HPLC-FLD法测定复方五指毛桃颗粒中补骨脂素的含量

目的建立高效液相荧光检测(HPLC-FLD)法测定复方五指毛桃颗粒中补骨脂素的含量。方法采用YMC-Pack-AM色谱柱(250 mm×4.6 mm,5μm);流动相为乙腈-水(34∶66),等度洗脱;流速为1.0 m L·min^(-1);FLD检测器的激发波长(Ex)为247 nm,发射波长(Em)为441 nm;柱温为30℃。结果补骨脂素进样量在3.117 0~2 992.200 0 ng(r=0.999 8)范围内与峰面积呈良好的线性关系,平均加样回收率为99.77%(n=9),RSD为1.38%。结论本研究所建立的HPLC-FLD法简便、准确、稳定,可用于复方五指毛桃颗粒中补骨脂素的含量测定,为复方五指毛桃颗粒的质量评价提供了参考。

基于HiCapt Benzo固相萃取前处理的HPLC-FLD法检测油茶籽油中苯并(a)芘

为了建立一种基于Hi Capt Benzo固相萃取快速前处理的,更灵敏、准确的高效液相色谱-荧光检测法,以用于油茶籽油中苯并(a)芘的检测。油茶籽油样品以正己烷溶解后,用Hi Capt Benzo专用固相萃取柱净化。检测条件为:LC-PAHs专用色谱柱;50%乙腈-50%水为流动相,流速1.0 m L/min;荧光检测器;外标法定量。研究结果表明,苯并(a)芘标准曲线在0.1~200 ng/m L范围内,线性关系好(R^2=0.9993);检测限很低(0.0213~0.0246μg/kg)。该法用于4个油茶籽油样品加标检测,回收率为93.06%~104.52%,相对标准偏差(RSD)为2.12%~3.98%。本文所建固相萃取-高效液相色谱(带荧光检测器)法前处理简单,结果准确可靠,是油茶籽油苯并(a)芘高效检测的适宜方法。

香豆素类荧光衍生试剂的合成及其柱前衍生氟虫腈HPLC-FLD检测方法的建立

以4-(二乙氨基)水杨醛为原料,经缩合成环、水解反应合成一种结构新颖的香豆素类荧光衍生试剂7-(二乙氨基)-2-氧-2H-色酮-3-羧酸(记为L1);建立并优化L1与氟虫腈衍生化反应体系,优化后条件如下:催化缩合剂为1-(3-二甲基氨基丙基)-3-乙基碳二亚胺盐酸盐/4-二甲氨基吡啶,反应溶剂为二氯甲烷,L1与氟虫腈用量比为11∶1,反应时间为60 min,衍生温度为45℃;对衍生产物N-(3-氰基-1-(2,6-二氯-4-(三氟甲基)苯基)-4-((三氟甲基)亚磺酰基)-1H-吡唑-5-基)-7-(二乙氨基)-2-氧-2H-色酮-3-甲酰胺(记为SF1)进行分离和鉴定;在此基础上,建立氟虫腈柱前衍生化高效液相色谱-荧光检测方法,方法的检出限达到0.01μg/L,定量限为0.036μg/L。该方法具有较好的灵敏度、精确性和可靠性,可应用于农产品中氟虫腈残留的检测。

GPC-HPLC-FLD法测定动植物油脂中的苯并(a)芘

建立动植物油脂中苯并(a)芘残留量的凝胶净化-高效液相色谱-荧光检测的测定方法。方法采用凝胶色谱净化系统处理样品,可除去油脂中甘油三酯等杂质的干扰。色谱条件:Hypersil ODS2(150mm×4.6mm,5μm)反相色谱柱,流动相为甲醇-水(94:6,V/V),流速1.0mL/min,激发波长365nm,发射波长406nm,柱温30℃。方法的检出限0.1μg/kg,线性范围0.1～50μg/kg,加标回收率92.0%～106.0%,相对标准偏差为1.86%(n=6)。该法具有样品预处理简单、灵敏度高、精密度高等优点,可用于动植物油脂样品中苯并(a)芘的快速准确测定。

基于HPLC-FLD靶向分析古茶树游离氨基酸积累特征

游离氨基酸是贡献茶汤鲜味的主要物质。乔木型和灌木型古茶树茶鲜叶经红茶加工工艺制成的干茶,其鲜味特征突出,但目前对古茶树茶鲜叶及制成的干茶中游离氨基酸的积累特征尚不清楚。本研究基于高效液相色谱-荧光检测器(HPLC-FLD)结合化学计量学方法靶向分析乔木型、灌木型古茶树及福鼎大白茶鲜叶和干茶样品中18种游离氨基酸含量。结果表明,茶鲜叶和干茶样品中茶氨酸含量最高,且在乔木型和灌木型古茶树鲜叶中存在显著差异;干茶中鲜味氨基酸含量减少,甜味和苦味氨基酸含量变化不明显。主成分分析结果显示,茶鲜叶样品游离氨基酸含量聚类明显,而干茶则呈现重叠或分散特征。不同树型古茶树鲜叶游离氨基酸积累存在差异,加工可改变游离氨基酸代谢,促进红茶品质形成。

腺嘌呤柱前衍生化-HPLC-FLD法测定3-氯-1,2-丙二醇的方法优化

3-氯-1,2-丙二醇(3-MCPD)经高碘酸钠溶液氧化裂解、腺嘌呤衍生化后的产物——1,N6-亚乙烯基腺嘌呤(ε-Ade)为强荧光物质,通过对其荧光光谱与重要影响因素进行研究与优化,结合测定体系背景干扰的抑制,对高效液相色谱-荧光法(HPLC-FLD)测定3-MCPD水溶液的条件进行了优化。得到优化条件为:使用耐碱性反相C18色谱柱进行测定,流动相中甲醇体积分数为20%,水相为pH 9.0的碳酸钠-碳酸氢钠缓冲液。食用油中3-MCPD的测定需以0.01 g/mL的NaCl溶液作为萃取水相,氧化裂解3-MCPD的高碘酸钠可采用等量的亚硫酸钠还原、1.1倍量的醋酸铅沉淀予以去除,从而抑制空白峰的干扰,将该方法应用于多种食用植物油样品的测定,结果表明:该方法准确度高、重现性好(RSD在0.32%~4.63%之间);样品谱图显示基质干扰很小,方法选择性高。

保健品中褪黑素含量测定的HPLC-DAD法和HPLC-FLD法的比较

目的:比较高效液相色谱-二极管阵列检测器(High Performance Liquid Chromatography-Diode Array Detection,HPLC-DAD)法和高效液相色谱-荧光检测器(High Performance Liquid Chromatography Fluorescence Detection,HPLC-FLD)法测定保健品中褪黑素含量的优劣。方法:样品经甲醇提取稀释后,采用高效液相色谱仪进行测定,色谱柱为中谱红C18(150 mm×4.6 mm,5μm),流动相为甲醇和0.05%三氟乙酸,DAD检测波长为222 nm;FLD激发光波长为286 nm,发射光波长为352 nm。结果:HPLC-DAD法在0.060~6.000μg·mL^(-1)线性关系良好,相关系数大于0.999,检出限为2.7 mg·kg^(-1),定量限为9.0 mg·kg^(-1),方法回收率为94.9%~108.2%,RSD小于5%;HPLC-FLD法在0.0010~0.0500μg·mL^(-1)线性关系良好,相关系数大于0.999,检出限为0.0065 mg·kg^(-1),定量限为0.022 mg·kg^(-1),方法回收率为81.4%~96.8%,RSD小于5%。结论:两种方法均可以测定保健品中褪黑素含量,HPLC-FLD法灵敏度优于HPLC-DAD法,可作为褪黑素含量测定的首选方法,HPLC-DAD法准确度优于HPLC-FLD法,可作为褪黑素含量测定的备选方法。

UPLC-MS/MS法检测3种食品中松仁过敏原

基于食品基质中松仁过敏原Pin k 2建立了一种超高效液相色谱-串联质谱法。将松仁经过研磨、脱脂、浸提、酶解后经Easy-nLC 1000-QExactive高分辨质谱仪进行分离分析,结合Uniprot蛋白数据库以及ProteinPilotTM软件对质谱图进行数据处理,经BLAST验证特异性,最终筛选3条松仁特异性肽段。方法学验证结果表明,方法在0.001~50mg/mL范围内线性关系良好,定量限为1mg/kg;在饼干、巧克力和饮料3种空白基质中的平均回收率为88.50%~107.57%,相对标准偏差不高于6.08%,基质效应为89.77%~96.13%。该方法具有灵敏度高、特异性好的优势,可应用于饼干、巧克力、饮料等食品样品中松仁过敏原的检测,为我国食品标签真实性检验及食品中隐性过敏原的检测提供技术支持。

高效液相色谱及其串联质谱技术在牙膏风险物质分析中的应用

牙膏是日常生活中必不可少的口腔清洁护理用品,牙膏的基料较为复杂,牙膏中潜在的风险物质对人体存在一定危害,因此牙膏产品的安全性已成为当今社会关注的焦点之一。利用现代先进的检验检测技术对牙膏中潜在的风险物质进行分析、研究,将有利于实现对牙膏产品的安全监管,本文综述了近几年来高效液相色谱及其串联质谱技术在牙膏产品检验标准和检验方法开发等方面的研究以及应用进展,一定程度上能为牙膏产品的质量控制和科学监管提供参考。

高效液相荧光色谱法同时测定六神曲中黄曲霉毒素、玉米赤霉烯酮和赭曲霉毒素A

目的建立一种用免疫亲和柱净化-柱后光化学衍生-高效液相色谱同时检测六神曲中黄曲霉毒素、玉米赤霉烯酮和赭曲霉毒素A的方法。方法样品采用60%乙腈超声提取,免疫亲和柱净化,采用XBridge^(®)Phenyl苯基色谱柱(4.6 mm×250 mm,5μm),以乙腈和0.1%磷酸溶液为流动相,梯度洗脱,光化学衍生仪衍生,通过切换荧光波长检测。结果黄曲霉毒素、玉米赤霉烯酮和赭曲霉毒素A标准曲线的线性范围分别为0.006~0.108、0.500~2.500和0.202~1.009 ng,6种毒素的线性关系在0.9994以上,检出限分别为1.2、100.0和40.3 ng/ml,平均加标回收率为73.2%~92.3%,相对偏差为2.1%~5.4%。结论该方法具有专属性强、操作方便等特点,能够有效用于六神曲中3种毒素的同时检测和安全质量控制。

溶剂提取-高效液相色谱法测定大气颗粒物中18种多环芳烃

建立大气颗粒物PM2.5中18种多环芳烃的样品快速溶剂提取结合高效液相色谱的测定方法。将1/2玻璃滤膜剪碎后加入2.0 mL乙腈,于20℃水浴超声提取30 min,提取液经0.22μm有机相滤膜过滤,多环芳烃C18专用柱分离,以乙腈-水作为流动相进行梯度洗脱,采用紫外串联荧光检测器-高效液相色谱仪检测,以色谱峰面积外标法定量。18种PAHs的质量浓度在0.01~0.50μg/mL范围内与色谱峰面积线性关系良好,相关系数不小于0.999,检出限为0.03~0.47 ng/m^(3),样品加标平均回收率为75.6%~114.7%,相对标准偏差为0.09%~3.78%(n=7)。该方法简便、快速、准确、灵敏,可应用于大气颗粒物PM2.5中18种多环芳烃的测定。