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.

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.

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.

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.

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.

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.

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。

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。

九蒸九制对鸡头黄精理化性质及抗氧化性的影响

为了探究蒸制处理对鸡头黄精有效成分及代谢物种类和含量影响,采用低场核磁、苯酚-浓硫酸法、高效液相色谱-蒸发光散射检测法(HPLC-ELSD)和液相色谱-质谱技术(LC-MS)等对其中的水分分布、多糖含量、单糖组成和代谢产物等进行分析。结果表明,多次蒸制后,鸡头黄精结合水的含量、多糖含量逐渐降低,水提液pH值逐渐降低呈弱酸性达到4.07,还原糖、总酚、黄酮含量逐渐升高分别达到28.69%、10.02 mg/g和0.69%,抗氧化性逐渐增强,ABTS抗氧化能力在7制达到最高为0.73 mmol/L,较1制增加0.35 mmol/L,DPPH自由基清除率和FRAP值在8制达到最高分别为81.95%,1.97 mmol/L,较1制分别增加50.92%,1.72 mmol/L;同时蔗糖逐渐水解从18.53mg/g到7.62mg/g,葡萄糖和果糖含量提高,分别由1制0.00和11.30mg/g,达到9制17.25和230.89 mg/g。选取一制与九制黄精进行代谢物差异分析,在正离子模式下共检测到1310种代谢物,差异代谢物有176种(按其特性分为38类),在负离子模式下共检测到1841种代谢物,差异代谢物有148种(按其特性分为26类)。黄精经蒸制后有效成分差异性显著,对鸡头黄精炮制加工提供科学依据。

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.

低盐雪菜中呈味核苷酸关联物的检测及贮藏过程中的变化

为探明低盐雪菜中呈味核苷酸关联物在贮运期间的变化规律,建立高效液相色谱检测方法,分析低盐雪菜在(25±5)℃贮藏(J-25)、(4±1)℃贮藏(J-4)、灭菌后(25±5)℃贮藏(M-25)和灭菌后(4±1)℃贮藏(M-4)期间感官品质和呈味核苷酸关联物含量的变化。结果表明,12种呈味核苷酸关联物在33 min内有效分离。灭菌和冷藏均能抑制雪菜贮藏期间感官品质和呈味核苷酸关联物的劣化,且灭菌冷藏组合的效果最佳,M-4组雪菜中三磷酸腺苷(adenosine triphosphate,ATP)和肌苷酸含量在第60天仍分别是初始值的29.7%和66.4%,且感官品质合格。雪菜在(25±5)℃贮藏期间与ATP相关的核苷酸关联物总量呈先增加后迅速降低的趋势,其中J-25组雪菜仅有9 d的感官合格期。灭菌和冷藏能够有效抑制雪菜中核酸代谢的呈味核苷酸(腺苷酸、鸟苷酸、胞苷酸、尿苷酸)在贮藏期内的变化,M-4组雪菜中这4种核苷酸总量在贮藏末期仍有4.30 mg/100 g。低盐雪菜中发酵微生物的代谢和较高的温度加快了呈味核苷酸关联物在贮藏期间的劣变,灭菌和冷藏有利于呈味核苷酸关联物的保持,研究结果可为低盐雪菜的加工和贮藏提供一定的理论支撑。

高效液相色谱法同时检测特殊用途饮料中常见的咖啡因等6种食品添加剂

目的建立使用高效液相色谱仪同时检测特殊用途饮料中的咖啡因、糖精钠、安赛蜜、柠檬黄、胭脂红、日落黄等6种食品添加剂的方法。方法仪器使用C18色谱柱,流动相采用甲醇与0.02mol/L乙酸铵溶液(不需要调节pH值),经梯度洗脱,通过四个检测波长通道同时采集色谱图和光谱图进行检测分析。结果上述6种食品添加剂线性范围在1.00 mg/L~100.0mg/L,相关系数均在0.9999以上,回收率为91.0%~108.2%。结论本方法操作简单、快速,可用于同时检测特殊用途饮料中的咖啡因等6种食品添加剂。

酸奶中乙酰磺胺酸钾、苯甲酸、山梨酸和糖精钠的检测方法

[目的]建立使用高效液相色谱仪同时检测酸奶中的乙酰磺胺酸钾等4种食品添加剂的方法。[方法]酸奶样品经过蛋白沉淀剂沉淀蛋白后高速离心,经0.22μm微孔滤膜过滤后上机测定。仪器使用C18色谱柱,流动相采用甲醇与0.02 mol/L乙酸铵溶液(不需调节pH值),检测波长为227 nm。[结果]4种添加剂线性范围1.00~50.0 mg/L,相关系数均在0.999 9以上,回收率91.2%~104.8%。[结论]该方法操作简单、快速,可用于同时检测酸奶中的乙酰磺胺酸钾、苯甲酸、山梨酸和糖精钠4种食品添加剂。

植物中1⁃脱氧野尻霉素特异性存在的考证

1⁃脱氧野尻霉素(DNJ)是桑树中最具有特征性、标志性的生物碱,具有调节糖脂代谢、抗菌、抗病毒等药理活性,是一种极具开发价值的天然活性产物。目前DNJ检测方法主要为柱前衍生高效液相色谱⁃荧光检测法,该方法能够检测到所有与荧光剂结合生成的络合物,但对被检测的物质无法进行定性,往往造成假阳性。通过对桑科植物和已报道含有DNJ的非桑科植物进行检测分析,利用柱前衍生高效液相色谱⁃荧光检测法与高效液相色谱⁃质谱(HPLC⁃MS)检测法相结合,挖掘并考证含有DNJ的植物种类,为DNJ的开发利用提供更广泛的原料素材。检测发现,除了桑树,其他常见桑科植物菠萝蜜、全叶无花果、小叶榕、裂叶无花果、构树、大叶榕、橡皮树、柳叶榕中均不含有DNJ;非桑科植物也只有风信子中含有DNJ;常规桑品种强桑1号的桑叶DNJ含量是风信子叶片DNJ含量的212倍。结果表明,对于植物中DNJ的检测,应先通过HPLC⁃MS进行定性研究,然后再通过柱前衍生高效液相色谱⁃荧光检测法进行定量检测,以避免出现假阳性。

高效液相色谱-紫外检测法同时测定类鼻疽患者血浆中亚胺培南、美罗培南和头孢他啶的浓度

目的建立一种快速、经济的高效液相色谱-紫外检测法(HPLC-UV),用于同时测定人血浆中亚胺培南、美罗培南和头孢他啶的药物浓度。方法采用Millipore 10KD超滤离心去蛋白,使用互为内标法,色谱柱为SunFire-C18柱(4.6 mm×250 mm,5µm);预柱为C18柱(4.0 mm×2.1 mm,5µm),流动相为0.1 mol·L^(-1)的3-(N-吗啡啉)丙磺酸(pH=7.0)和乙腈,梯度洗脱,检测波长299nm,流速1.0mL·min^(-1),运行时间30min,进样体积30µL。结果亚胺培南、美罗培南和头孢他啶的保留时间分别为6.699 min、10.795 min和8.722 min。血浆内源性物质对样品的测定无干扰,峰形良好。该方法具有良好的线性、准确度和精密度。不同浓度的样品在–20℃反复冻融、–20℃长期冷冻和4℃(48 h)下均表现出了较高的稳定性。结论该方法操作成本低、专属性强、分离效果好,可用于类鼻疽患者血浆中亚胺培南、美罗培南和头孢他啶治疗药物浓度的测定。

高效液相色谱-串联质谱法同时测定饲料中乙氧基喹啉及其伴生物质

本研究旨在建立一种应用高效液相色谱-串联质谱(HPLC-MS/MS)技术同时测定饲料中乙氧基喹啉(EQ)、对氨基苯乙醚(PD)、非那西丁(PC)、乙氧基喹醌亚胺(EQI)和乙氧基喹啉二聚体(EQDM)含量的方法。饲料样品用乙腈提取,经BONDESIL-SI多重杂质吸附材料净化,采用HPLC-MS/MS测定,以0.1%甲酸水溶液-0.1%甲酸乙腈溶液作为流动相,梯度洗脱,Waters BEH C_(18)色谱柱分离。结果表明:通过饲料基质匹配绘制标准曲线,EQ、PD、PC、EQI和EQDM在5~500μg/L范围内线性关系良好[决定系数(R^(2))>0.9950]。方法中EQ、PD和PC的检出限和定量限分别为3.0和10.0μg/kg,EQI和EQDM的检出限和定量限分别为1.5和5.0μg/kg。EQ、PD、PC、EQI和EQDM在3个添加水平(20、50、100μg/kg)的平均回收率为73.77%~98.77%,批内相对标准偏差(RSD,n=6)<10%,批间变异系数<12%。该方法前处理简单,操作方便,适用于饲料中EQ及其伴生物质的同步测定。

济南城区冬季PM_(2.5)中硝基苯酚类化合物昼夜变化特征及生成机理

硝基苯酚类化合物(Nitrophenols,NPs)是细颗粒物中含氮有机物的重要组成部分,来自于污染源的一次排放或由前体物经过二次反应生成.采集了济南城区2021年12月17日—2022年1月19日冬季大气昼夜PM_(2.5)样品,利用超高效液相色谱-质谱联用仪定量分析了样品中的7种硝基苯酚类化合物.结果表明,济南市区冬季大气PM_(2.5)中ρ(∑NPs)范围为13.22—72.42 ng·m^(-3),平均值为(45.56±13.22)ng·m^(-3).单个硝基苯酚类化合物中,4-硝基苯酚(4NP)占比最大,与国内其他城市监测结果一致.清洁天和污染天对比分析发现硝基苯酚类化合物在污染天的浓度更高,除4-硝基愈创木酚和5-硝基邻甲氧基苯酚外,其余硝基苯酚类化合物均是污染天浓度高.昼夜浓度对比发现ρ(∑NPs)在白天和夜间时段分别为(41.5±16.35)ng·m^(-3)和(49.08±20.18)ng·m^(-3),大部分硝基苯酚类化合物的昼夜浓度呈现夜间浓度高于白天,但PM_(2.5)污染加重时,白天时段的硝基苯酚类化合物浓度明显升高,甚至高于夜间浓度.利用量子化学高斯程序计算发现夜间硝基苯酚生成更容易,这跟晚上时段观测的硝基苯酚浓度高的现象相一致.当苯酚邻位和对位的取代基是给电子基团可以减小O—H解离焓,有利于苯氧自由基的生成.化学反应动力学给出了2-硝基苯酚(2NP)和4NP的生成路径,其反应活化能分别为49.6 kcal·mol^(-1)和84.2 kcal·mol^(-1),生成速率常数分别为7.93×10^(-37) cm^(3)·molecules^(-1)·s^(-1)和5.75×10^(-60) cm^(3)·molecules^(-1)·s^(-1),可知在清洁干燥天气的时候,硝基苯酚化合物的生成是非常困难的.但当有水分子和氨气等催化剂的协助后,2NP和4NP生成的活化能明显减小,其生成反应速率常数显著增大,说明重污染过程中,湿度增加和有氨气存在时会促进硝基苯酚的生成和积累.研究结果为城市氮氧化物削减和含氮有机物的二次生成提供一定的科学支撑.

柱前荧光衍生化法检测降尘样品中的不饱和醛

本研究发展了一种柱前荧光衍生化方法,实现了重要环境污染物不饱和醛类化合物的高灵敏度、高选择性分析。该方法使用4-丁基羟氨-7-羟基香豆素(HAHC)作为荧光衍生试剂,结合高效液相色谱-荧光检测法(HPLC-FLD)实现了6种二烯醛的定性、定量分析。在实际样品分析中成功从积尘样品中检测出(E,E)-2,4-庚二烯醛、(E,E)-2,4-辛二烯醛、(E,E)-2,4-十一烷二烯醛。这种柱前衍生化法具有动态范围宽(2~2500nmol/L)、灵敏高(检出限为0.2nmol/L)、精密度好(日内相对标准偏差为2.17%~3.33%,日间相对标准偏差为2.28%~5.04%)等优点,且无需固相萃取等复杂前处理步骤,为痕量醛类污染物检测提供了有效手段。

超声萃取-高效液相色谱-串联质谱法测定土壤中三种硝基酚类化合物

硝基酚类化合物作为一类有机化工原料,具有高毒性和致癌性,可通过空气、水传播进入土壤造成污染,危害人类健康。以往采用气相色谱法和气相色谱-质谱法直接测定硝基酚类化合物,存在色谱灵敏度低、峰形差等问题。为提高灵敏度,通常需要对硝基酚类化合物进行衍生化处理,但衍生化方法步骤繁琐耗时。为实现土壤中硝基酚类化合物的快速准确分析,本文建立了超声萃取-高效液相色谱-串联质谱法分析土壤中三种硝基酚类化合物的方法。用二氯甲烷-正己烷(2∶1,V/V)混合溶剂超声萃取土壤中硝基酚类化合物,在超声萃取液中加入强碱性水溶液(pH>12),将下层有机相除去。将水溶液调至酸性(pH<2)后,用二氯甲烷-乙酸乙酯(4∶1,V/V)混合溶剂萃取三种硝基酚类化合物。萃取液浓缩后用10%乙腈-水溶液定容至10.0mL,高效液相色谱-串联质谱仪测定,外标法定量。性能评价的结果表明方法精密度(RSD<10%,n=6)和准确度都可以满足测定要求,三种硝基酚类化合物的方法检出限为0.1~0.2μg/kg,加标回收率为61.7%~90.8%。本方法具有前处理简单、检出限低等优点,可应用于土壤中硝基酚类化合物的测定和评估。