中空纤维液相微萃取同时快速研究6种黄酮类药物与蛋白的结合特性

将中空纤维液相微萃取(HFLPME)-高效液相色谱法(HPLC)与Bjerrum或Scatchard法结合,同时、快速研究了6种黄酮类化合物的蛋白结合率、结合常数和结合位点数.最佳萃取条件为:聚偏氟乙烯作为有机溶剂载体,正庚醇作为萃取相,搅拌速度900 r/min,萃取时间2h.在最佳条件下,二氢杨梅素、杨梅素、槲皮素...     

中空纤维碳纳米管/正辛醇固-液协同微萃取机理及其应用

讨论了以中空纤维为载体的碳纳米管/正辛醇固-液协同微萃取机理,建立了中空纤维碳纳米管/正辛醇固-液协同微萃取-高效液相色谱法同时测定复杂样品中微量咖啡酸、阿魏酸和肉桂酸含量的方法.以2.5 cm长的聚偏氟乙烯中空纤维为碳纳米管正辛醇分散液载体,供相为分析物的HCl(pH 2.1)溶液,接受相为pH 12.7的NaOH溶液,在35℃下,搅拌萃取60 min,萃取液进行高效液相色谱紫外检测.在优化的实验条件下,分析物的线性范围均在0.05～50 μg/L,r＞0.9990 (n=5);检出限均为0.015μg/L;日内与日间精密度均小于9.8％(n=9),平均回收率为93.8％～115.2％;富集倍数分别为514,942和1084倍.在以中空纤维为支持体的碳纳米管/正辛醇微萃取中,碳纳米管/正辛醇分散液嵌入中空纤维管壁上的微孔中形成了碳纳米管/正辛醇固-液微萃取单元束,对苯丙烯酸类化合物起到协同萃取作用.     

基于中空纤维液相微萃取的麻黄碱和伪麻黄碱优势构象的确定及含量测定

利用中空纤维液相微萃取方法(HF-LPME)分析麻黄碱和伪麻黄碱在不同基质中的优势构象,阐明了麻黄碱和伪麻黄碱的萃取机理;结合高效液相色谱(HPLC)建立了微量麻黄碱和伪麻黄碱的分离测定方法。以聚偏氟乙烯中空纤维为有机溶剂载体,正己醇为萃取溶剂,麻黄碱和伪麻黄碱的NaOH(5 mol/L)溶液为样品相,0.01 mol/L H2SO4溶液为接收相,在1200 r/min转速下萃取35 min,收集萃取液直接进行HPLC分析。麻黄碱和伪麻黄碱在水溶液中的线性范围为5～100 μg/L,检出限分别为1.9 μg/L和1.2 μg/L,富集倍数分别为38和61倍,平均回收率分别为100.6%±1.2%和103.2%±3.5%;在鼠尿液中的线性范围为100～5×104 μg/L,检出限分别为30 μg/L和42 μg/L,富集倍数分别为20和17倍,平均回收率分别为108.4%±4.4%和106.1%±5.4%。研究表明该方法操作简单,选择性高,适用于微量麻黄碱的含量测定和分析。     

基于中空纤维液相微萃取的大鼠体内大黄素及其代谢物分析

建立了中空纤维液相微萃取(HFLPME)耦合高效液相色谱法(HPLC)用于测定血浆和尿液中大黄素及其代谢物的浓度,比较了中药有效成分大黄素在不同性别大鼠体内的吸收和代谢能力,阐述了大黄素在体内的代谢和转化过程。本实验以聚偏氟乙烯纤维为溶剂载体,正辛醇为萃取溶剂,对血浆和尿液样品进行HFLPME处理,萃取后挥干有机溶剂,用50 μL甲醇溶解,进行HPLC测定。在优化的微萃取条件下,血浆和尿液样品中大黄素及其代谢物标准曲线线性良好(相关系数(r)大于0.9960);检出限为0.1～3.0 μg/L;富集倍数为12.2～26.3;日内、日间精密度(以相对标准偏差(RSD)计)小于11.0%;血浆和尿液中代谢物的平均回收率为97.9%～103%。HFLPME操作简单,富集倍数高,能有效去除生物样品中复杂基体的干扰,适用于复杂样品中微量、痕量成分分析物的分析测定。     

水和生物体液中曲马多镇痛药的中空纤维膜液相微萃取

使用中空纤维膜液相微萃取技术(LPME-HFM)建立了从水和生物样品(尿和血浆)中提取曲马多的方法。在室温(20 ℃)下用聚偏氟乙烯中空纤维膜过滤提取样品。萃取过程中用4 μL甲苯作为萃取溶剂。用度冷丁作为内标,气相色谱法-氢火焰离子化检测器分析测定,最低检测限达0.01 mg/L(自来水、尿)或0.05 mg/L(血浆)。和传统的液液萃取方法相比,该方法集萃取和浓缩一步完成,更简便、快速、绿色环保。     

液相微萃取-离子色谱法测定污水中痕量芳香胺

基于中空纤维液相微萃取技术,建立了河流污水中两种芳香胺类物质（邻甲苯胺和对氯苯胺）的离子色谱分析方法。采用中空纤维液相微萃取和离子色谱联用技术,对中空纤维萃取条件进行优化。优化的萃取条件：萃取溶剂为正辛醇,供体相中NaOH的浓度为0.01mol/L, NaCl的浓度为500g/L,接受相中HCl的浓度为0.1 mol/L,搅拌速度为430r/min,萃取时间为30min,在优化条件下,邻甲苯胺的富集倍数为88倍,对氯苯胺的富集倍数为124倍。供体相中邻甲苯胺和对氯苯胺的浓度在0.005–0.1mg/L范围内成良好线性,相关系数为0.9998-0.9999 ,检出限为0.2-0.5μg /L,相对标准偏差为0.85-3.38 %。结论：这种方法操作简单,环境友好,提高了离子色谱检测芳香胺类物质的灵敏度。     

中空纤维液-液-液微萃取/HPLC分析人尿液中麻黄碱及伪麻黄碱

建立了中空纤维液-液-液微萃取高效液相色谱对人尿液中的麻黄碱和伪麻黄碱进行纯化、分离、富集以及测定的方法。采用中空纤维三相微萃取装置,考察了影响萃取的因素,确定了萃取条件:中空纤维壁上的有机相为正辛醇,以50μL盐酸溶液(pH 2.0)为接受相,在室温下萃取60 min。该条件下麻黄碱和伪麻黄碱的富集倍数分别为180倍和220倍,两者的线性范围分别为0.01～5 mg/L和0.005～0.75 mg/L,相关系数(r)分别为0.998 2、0.997 8,定量下限分别为0.01、0.005 mg/L。该方法使用极少量的有机溶剂,便可有效地对尿样中麻黄碱和伪麻黄碱进行纯化、分离和富集,萃取效率高,可用于尿液中麻黄碱和伪麻黄碱的同时测定。     

中空纤维膜液相微萃取-超高效液相色谱测定蒙药毛勒日-达布斯-4汤中两种生物碱

建立了将中空纤维膜液相微萃取（HF-LPME）技术与超高效液相色谱（UPLC）技术联用检测蒙药毛勒日-达布斯-4汤中2种生物碱（胡椒碱和荜茇宁）的分析方法。通过考察该HF-LPME方法的影响参数，优化了萃取实验条件。HF-LPME优化条件如下：空隙率大于50%的偏氟乙烯中空纤维膜，萃取溶剂为正辛醇，氯化钠质量浓度为10 g/L，室温振荡，振荡速度为173 r/min，萃取时间为128 min。结果表明：该HF-LPME-UPLC方法对胡椒碱和荜菝宁的检出限（LOD）分别为2.2和2.5 μg/L，相对标准偏差不大于7.8%（n=5）。胡椒碱和荜菝宁分别在100~8500 和8.3~5000 μg/L范围内具有良好的线性关系，胡椒碱和荜茇宁的富集倍数分别为59和65。该方法简便、快速、准确、环保，适用于蒙药中胡椒碱和荜菝宁含量的测定。     

三相中空纤维膜液相微萃取-高效液相色谱法测定水中痕量双酚A

建立了三相中空纤维膜液相微萃取-高效液相色谱(HF-LPME-HPLC)方法,用于分析测定水中痕量双酚A的含量.设计了三相中空纤维膜液相微萃取系统,优化的HP-LPME最佳萃取条件为:萃取剂为正辛醇,接受相NaOH浓度为0.09 mol/L,样品溶液pH=4.0,NaC1加入量为30 g/L,搅拌速度为900 r/min,萃取时间为60 min.萃取后取20 μL接受相进行色谱分析.在最佳萃取条件下,方法的线性范围为0.5～200 μg/L(r＞ 0.999),检出限(信噪比为3)为0.2 μg/L;富集因子为241;方法RSD＜3.2％ (n=3).在实际环境水样中添加5,20和50μg/L的双酚A标准物质,加标平均回收率为92.8％～101.9％.表明本方法可用于水中痕量双酚A的快速准确测定.     

中空纤维分散液膜富集稀土元素

采用2-乙基己基膦酸单-2-乙基己基酯(HEHEHP)-正庚烷为萃取剂,盐酸为反萃取剂,中空纤维膜作支撑膜,研究中空纤维分散液膜技术富集稀土镱(Yb~(3+))离子。考察了体系物性:反萃分散相中反萃剂浓度、萃取剂浓度、萃取剂与反萃剂体积比、料液相p H值、稀土离子浓度;流体流动状态:反萃分散相与料液相流速变化等因素对富集稀土离子的影响。中空纤维分散液膜富集Yb~(3+)的最佳条件为:萃取剂浓度为0.25 mol/L,反萃取剂HCl浓度为4.00 mol/L,萃取剂与反萃剂体积比为10∶40,料液相p H=2.80,稀土离子浓度为0.025 mol/L。反萃分散相体积流量和料液相体积流量较小时,萃取率随流量的增加呈现逐渐增大的趋势。若两相体积流量过大,反萃过程进行不完全,萃取率反而下降。研究结果表明,中空纤维分散液膜技术可实现稀土离子的有效富集。     

液相微萃取/后萃取技术在中药苯丙酸类化合物分析中的应用

初步阐明了液相微萃取/后萃取(LPME/BE)在苯丙酸类化合物中的萃取机理;建立了浓缩倍数与模型化合物分配系数及理化参数之间的关系.利用自制的液相微萃取装置,优化了LPME/BE条件:以聚偏氟乙烯纤维(MOF503)为溶剂载体,正庚醇为萃取剂,pH 3.0的HCl分析物水溶液为供相,pH 11.7的NaOH为接受相,搅拌速度为1800 r/min,萃取时间为60 min.萃取完成后经HPLC分析.模型化合物浓缩倍数EF与其正庚醇/水表观油水分配系数logP有良好线性,R2=0.9653.测得该方法的RSD内＜6.3%,RSD间＜6.6%;检出限为咖啡酸0.025 μg/L;阿魏酸0.250 μg/L;对羟基桂皮酸0.004 μg/L;对甲氧基桂皮酸0.100 μg/L;桂皮酸0.050 μg/L.双黄连口服液中咖啡酸平均回收率为100.3%;浓缩当归丸中阿魏酸平均回收率为99.2%;桂枝茯苓丸中桂皮酸平均回收率为99.4%.本法操作简便、快速、环境友好,能有效去除中药样品中复杂机体的干扰.     

Automated polyvinylidene difluoride hollow fiber liquid-phase microextraction of flunitrazepam in plasma and urine samples for gas chromatography/tandem mass spectrometry

A new polyvinylidene difluoride (PVDF) hollow fiber (200 μm wall thickness, 1.2 mm internal diameter, 0.2 μm pore size) was compared with two other polypropylene (PP) hollow fibers (200, 300 μm wall thickness, 1.2 mm internal diameter, 0.2 μm pore size) in the automated hollow fiber liquid-phase microextraction (HF-LPME) of flunitrazepam (FLNZ) in biological samples. With higher porosity and better solvent compatibility, the PVDF hollow fiber showed advantages with faster extraction efficiency and operational accuracy. Parameters of the CTC autosampler program for HF-LPME in plasma and urine samples were carefully investigated to ensure accuracy and reproducibility. Several parameters influencing the efficiency of HF-LPME of FLNZ in plasma and urine samples were optimized, including type of porous hollow fiber, organic solvent, agitation rate, extraction time, salt concentration, organic modifier, and pH. Under optimal conditions, extraction recoveries of FLNZ in plasma and urine samples were 6.5% and 83.5%, respectively, corresponding to the enrichment factor of 13 in plasma matrix and 167 in urine matrix. Excellent sample clean-up was observed and good linearities (r² = 0.9979 for plasma sample and 0.9995 for urine sample) were obtained in the range of 0.1–1000 ng/mL (plasma sample) and 0.01–1000 ng/mL (urine sample). The limits of detection (S/N = 3) were 0.025 ng/mL in plasma matrix and 0.001 ng/mL in urine matrix by gas chromatography/mass spectrometry/mass spectrometry.     

Hollow fiber‐based liquid membrane microextraction combined with high‐performance liquid chromatography for extraction and determination of trimetazidine in human plasma

A hollow fiber‐based liquid phase microextraction strategy combined with high‐performance liquid chromatography was evaluated for the quantitative determination of trimetazidine in human plasma. Trimetazidine was extracted from a 2.1 mL basified plasma sample (donor phase) into the organic solvent (n‐octanol) impregnated in the pores of a hollow fiber and then extracted into an acidic solution (acceptor phase) inside the lumen of the hollow fiber. The result showed that transport of drugs from alkaline sample solution into 0.5 m HCl occurred efficiently when 25 μL of 250 mm sodium 1‐octanesulfonate was added into the donor phase. Several parameters influencing the efficiency of the method, such as the nature of organic solvent used to impregnate the membrane, compositions of donor phase and acceptor phase, type and concentration of carrier, extraction time, stirring rate and salt concentration, were investigated and optimized. Under the optimal conditions, the calibration curves were obtained in the range of 5–200 ng/mL with reasonable linearity (r > 0.9980). The method was successfully applied to determine the concentration of trimetazidine in human plasma. Copyright © 2012 John Wiley & Sons, Ltd.     

中空纤维液相微萃取-高效液相色谱法测定纺织品中10种含氯苯酚类化合物

建立了中空纤维液相微萃取-高效液相色谱法测定纺织品中10种含氯苯酚类化合物的方法。系统地优化了影响萃取效率的因素,得到的最佳萃取条件为：萃取溶剂为正己烷,接受相NaOH溶液的浓度为0.10 mol/L,萃取时间为60 min,搅拌速度为600 r/min。在最佳萃取条件下,10种含氯苯酚在0.01～1.00 mg/L范围内线性关系良好（r>0.999）,10种含氯苯酚的检出限（信噪比为3）为0.01 mg/kg,富集倍数为95～101。在空白样品中添加0.01、0.05和0.1 mg/kg 3个不同水平的10种含氯苯酚类化合物,其平均回收率为78.8%～105.1%,相对标准偏差为0.3%～7.3%。研究结果表明该方法灵敏度高、简便、准确,可用于纺织品中含氯苯酚类化合物的测定。     

中空纤维三相液相微萃取-薄层色谱分离同步荧光法测定酱油中的色胺含量

以三相中空纤维液相微萃取(HF-LPME)作为样品前处理方法,结合薄层色谱分离,同步荧光光谱法测定酱油中色胺的含量。通过单因素实验确立的萃取最优条件为:样品溶液p H值为12.0,正辛醇为萃取溶剂,0.1 mol/L的HCl为接受相,搅拌速度为590 r/min,萃取时间为60 min;取20μL接受相进行TLC分析,样品点用异丙醇溶解后离心分离;采用同步荧光在λem=350.4 nm处进行定量分析。在最佳萃取条件下,方法的线性范围为0.32~50 mg/L(r0.978 0),检出限(S/N=3)为0.32 mg/L。酱油样品的加标回收率为87.5%~107.7%,相对标准偏差(RSD)不大于6.6%。该方法操作简单、绿色高效、灵敏度高,可用于酱油中色胺的快速准确测定。     

中空纤维膜液相微萃取-高效液相色谱联用技术测定尿液中痕量己烯雌酚

采用中空纤维液相微萃取与高效液相色谱联用技术测定了尿液样品中的痕量己烯雌酚;考察了样品相酸度、中间相种类、接收相浓度、搅拌速度、萃取时间等对液-液-液三相微萃取效率的影响,进而确定了最佳萃取条件.结果表明,当样品相pH为2.5,中间相为甲苯,接收相为3μL 0.25mol/L氢氧化钠溶液,搅拌速度为800r/min,萃取时间为50min时,萃取效率最佳.在最佳萃取条件下,样品的回收率为76.4%,相对标准偏差为3.8%.     

Evaluation of two membrane‐based microextraction techniques for the determination of endocrine disruptors in aqueous samples by HPLC with diode array detection

In this study, the viability of two membrane‐based microextraction techniques for the determination of endocrine disruptors by high‐performance liquid chromatography with diode array detection was evaluated: hollow fiber microporous membrane liquid–liquid extraction and hollow‐fiber‐supported dispersive liquid–liquid microextraction. The extraction efficiencies obtained for methylparaben, ethylparaben, bisphenol A, benzophenone, and 2‐ethylhexyl‐4‐methoxycinnamate from aqueous matrices obtained using both approaches were compared and showed that hollow fiber microporous membrane liquid–liquid extraction exhibited higher extraction efficiency for most of the compounds studied. Therefore, a detailed optimization of the extraction procedure was carried out with this technique. The optimization of the extraction conditions and liquid desorption were performed by univariate analysis. The optimal conditions for the method were supported liquid membrane with 1‐octanol for 10 s, sample pH 7, addition of 15% w/v of NaCl, extraction time of 30 min, and liquid desorption in 150 μL of acetonitrile/methanol (50:50 v/v) for 5 min. The linear correlation coefficients were higher than 0.9936. The limits of detection were 0.5–4.6 μg/L and the limits of quantification were 2–16 μg/L. The analyte relative recoveries were 67–116%, and the relative standard deviations were less than 15.5%.