LC Determination of Mono-Substituted Phenols in Water Using Liquid–Liquid–Liquid Phase Microextraction

A simple liquid–liquid–liquid microextraction device of new design was used to pre-concentrate phenols from water samples before liquid chromatographic (LC) analysis. Extraction was induced by the pH difference inside and outside an organic phase located at the interface. The pH of the donor phase outside the organic phase was adjusted to 1 with HCl whereas the acceptor phase was a basic solution at pH 13. On stirring neutral phenols were extracted into the organic solvent then back-extracted into 1 μL of basic acceptor solution suspended from the tip of a micro syringe. The acceptor phase was then withdrawn into the micro syringe and injected directly into the LC. The technique uses a low-cost disposable extraction ‘device’ and is very convenient to operate. Up to 230-fold enrichment of analytes could be achieved. This procedure could also serve as a sample clean-up step because neutral and basic compounds were not extracted into the acceptor phase. The RSD (n = 5) was better than 6.2% and the linear calibration range was from 1 to 1000 µg–L⁻¹ with r ² ≥ 0.992.Optimization of experimental conditions (rate of stirring, ionic strength of the sample solution, concentration of reagents, time of extraction, and organic solvent volume) were also examined. The method was applied to the determination of phenols in tap and well waters.Revised: 14 February and 29 March 2005     

液相微萃取/后萃取-高效液相色谱法测定氧化苦参碱和苦参碱

建立了液相微萃取/后萃取-高效液相色谱法测定中药苦参、复方苦参注射液中氧化苦参碱和苦参碱含量的方法。利用自制的微萃取装置,选择异丙醇为萃取有机溶剂,2.00 mL NaOH(pH9)为供相,HCl(pH4)为接受相,聚丙烯腈纤维的长度为10 cm,搅拌速度为1500 r/min,萃取时间为30 min。萃取完成后,经高效液相色谱仪分析,测得氧化苦参碱和苦参碱线性范围分别为11~437 mg/L和10~433 mg/L;检出限均为1.0mg/L;相对标准偏差分别小于9.4%和6.7%。复方苦参注射液中氧化苦参碱和苦参碱的平均回收率分别为83.0%~116.1%和108.8%~117.8%;苦参药材中氧化苦参碱的平均回收率为104.3%~114.7%。本方法有机溶剂用量少,可有效去除复杂机体的干扰,测得结果满意。     

LC Determination of Phthalate Esters in Water Samples Using Continuous-Flow Microextraction

A novel method, continuous-flow microextraction (CFME) combined with liquid chromatography (LC) with variable-wavelength detector (VWD), has been developed for the determination of three phthalate esters (dimethyl phthalate (DMP), diethyl phthalate (DEP), and di-n-butyl phthalate (DnBP)) in water samples. Experimental parameters including extraction solvent, solvent drop volume, flow rate of sample solution, extraction time and ionic strength, which affected the extraction efficiency, were studied and optimized. Under the optimum extraction conditions, the method yields a linear calibration curve in the concentration range of 10–10,000 ng mL^?1 for target analytes. The enrichment factors of this method for DMP, DEP and DnBP reached at 27, 44 and 20, respectively, and the detection limits were 2, 1 and 5 ng mL^?1, respectively. Good repeatability of extraction was obtained with relative standard deviations below 8.6%. The results demonstrated that CFME followed by LC-VWD is a simple and reliable technique for the determination of phthalate esters in water samples.     

Determination of Trace Chloroanilines in Environmental Water Samples Using Hollow Fiber-Based Liquid Phase Microextraction

A liquid phase microextraction method using hollow fiber to support extraction solvent was developed for enrichment of trace level chloroanilines in environmental water samples. Target analytes, 2-chloroaniline, 3-chloroaniline, 2,3-dichloroaniline, 2,4-dichloroaniline, 3,4-dichloroaniline, and 3,5-dichloroaniline were determined using gas chromatography-flame ionization detector after extraction. Experimental conditions that affect extraction efficiency were investigated and optimized. The proposed method showed a wide linear range from lower ??g L^?1 to 1,000 ??g L^?1, low detection limits (??5.1 ??g L^?1), and reasonable relative standard deviations (RSDs < 13%). Feasibility of the method was evaluated by analyzing river water samples collected from the Hudson River and the East River in New York City.     

基于离子液体的液相微萃取-高效液相色谱法测定水中有机磷农药

建立了基于1-丁基-3-甲基咪唑六氟磷酸盐离子液体的液相微萃取-高效液相色谱分析水样中甲拌磷、对硫磷和辛硫磷的方法。考察了萃取溶剂、萃取溶剂与样品溶液体积比、萃取时间、萃取温度和搅拌速度对液相微萃取的影响。在优化的萃取条件下,甲拌磷、对硫磷、辛硫磷3种农药的富集倍数分别为665、630和553倍;方法有好的线性范围(0.01-1μL/L)和低的检出限(0.001-0.01μL/L,S/N=3)。对0.1μL/L的甲拌磷,对硫磷和辛硫磷测定3次的相对标准偏差分别为3.44%、10.50%和2.41%。     

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.     

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。     

离子液体分散液相微萃取-高效液相色谱法测定番茄中的氨基甲酸酯类农药

将离子液体1-丁基-3-甲基咪唑六氟磷酸盐([BMIm][PF6])作为萃取剂,采用分散液相微萃取-高效液相色谱法分析番茄样品中的4种氨基甲酸酯类农药残留,并考察了不同缓冲溶液浓度、pH值及萃取时间等因素对分散液相微萃取效果的影响。在优化实验条件下,该方法对涕灭威、克百威、甲萘威、异丙威的富集倍数分别为317、430、545、625,且具有良好的线性范围(0.01～10mg/L)和较低的检出限(0.12～0.43μg/L),对涕灭威、克百威、甲萘威、异丙威测定5次的相对标准偏差为5.3%～5.5%,用于示范区采集的番茄样品分析,平均加标回收率为75%～120%。研究表明[BMIm][PF6]可有效地萃取番茄中的氨基甲酸酯类农药残留,具有萃取效率高、灵敏度高、操作简单、绿色环保等优点,可以满足番茄样品中氨基甲酸酯类农药残留的检测要求。     

Separation and Determination of Amitriptyline and Nortriptyline in Biological Samples Using Single-Drop Microextraction with GC

The combination of liquid phase microextraction (LPME) based on a single drop and gas chromatography flame ionization detector (GC-FID) was used for separation and determination of amitriptyline and nortriptyline in human plasma and urine samples. The sample solution was kept alkaline (pH 12), then a microdrop of organic solvent (isooctane) was suspended in the donor solution; after extraction, the organic microdrop was injected into the GC-FID. Experimental LPME conditions were optimized. Finally, the enrichment factors (89.5?C139.0), the relative standard deviation (RSD%, n = 5) 1.1?C8.5, linearity ranges (0.05?C20 ??g mL^?1), and the limits of detections (0.01, 0.02 ??g mL^?1) for selected drugs were evaluated.     

Determination of Hg(II) in Environmental Water Samples by Dispersive Liquid Phase Microextraction Combined with Flame Atomic Absorption Spectrometry

In this study, a method of dispersive liquid phase microextraction combined with the flame atomic absorption spectrometry was proposed for the determination of trace Hg using diphenylthiocarbazone as chelating reagent. Several factors which have effect on the microextraction efficiency of Hg, such as pH, extraction and dispersive solvent type and their volume, concentration of the chelating agent, extraction time were investigated, and the optimized experimental conditions were established. After extraction, the enrichment factor was 68. The detection limit of the method was 45 ng mL^?1, and the relative standard deviation for eight determinations of 2 μg mL^?1 Hg was 1.7%. The results for the determination of Hg in environmental water samples (tap water, well water, mineral water and Caspian sea water) have demonstrated the applicability of the proposed method.     

Enhancement of Sensitivity for Determination of Phenols in Environmental Water Samples by Single-drop Liquid Phase Microextraction Using Ionic Liquid prior to HPLC

In recent years, single-drop liquid phase microextraction (LPME) has attracted great attentions, and provides some merits including rapidness, simplicity, and low cost. In general, there are two modes of LPME sampling: direct-immersed LPME (DI-LPME) and h…     

磁性石墨烯固相萃取-分散液液微萃取-气相色谱法测定水和绿茶中酰胺类除草剂残留

采用磁性石墨烯纳米复合材料作为磁性固相萃取剂进行磁性固相萃取,再进行分散液液微萃取,采用气相色谱建立了高灵敏测定环境水样和绿茶中5种酰胺类除草剂残留的方法。对影响萃取效率的诸因素进行了优化。在优化条件下,5种酰胺类除草剂的富集倍数在3399～4002之间,甲草胺、乙草胺、异丙甲草胺、丁草胺和丙草胺浓度在0.1～50μg/L范围内与峰面积呈良好的线性关系,线性相关系数在0.9973～0.9993之间,检出限在0.01～0.03μg/L范围内。本方法应用于河水、自来水和绿茶样品的分析,平均加标回收率在80.2%～108.4%之间,相对标准偏差在3.8%～5.8%之间。本方法操作简单、灵敏、富集倍数高。     

析相微萃取-石墨炉原子吸收法测定生物样品中痕量镉

本文以双硫腙为络合剂,乙酸乙酯为萃取剂,建立了析相微萃取-石墨炉原子吸收光谱法测定环境生物样品中痕量镉的分析方法.考察了析相规律及影响萃取的酸度条件及络合剂用量等因素,方法线性范围为0.005～0.20μg/L,相对标准偏差(RSD)为4.0%(n=7),与未经析相微萃取方法测定相比,灵敏度提高了20倍.所建立的方法用于测定国家标准物质杨树叶、灌木枝叶、人发中镉的含量,结果与参考值具有良好的一致性.     

Rapid Ultrasound-Assisted Emulsification Microextraction Combined with COU-2 Dispersive Micro-solid Phase Extraction for the Determination of Azole Antifungals in Milk Samples by HPLC-DAD

A rapid, simple, and efficient method using ultrasound-assisted emulsification microextraction combined with dispersive micro-solid phase extraction (USAE-D-µ-SPE) was developed for detection and quantification of three azole antifungals in milk samples by high-performance liquid chromatography diode array detector. In this study, mesoporous carbon, COU-2, was used as sorbent in USAE-D-µ-SPE for the extraction and preconcentration of analytes. Several important experimental parameters, including type of deproteinized solvents, desorption time, type of extraction solvents, volume of extraction solvent, extraction time, emulsification time, sample pH, salt addition, and mass of COU-2 sorbent, were optimized using spiked milk samples. Under the optimum extraction and detection conditions, three azole antifungals, namely ketoconazole, clotrimazole, and miconazole, were determined within 20 min, with good linearity of matrix-matched calibration in the range of 0.5–5000.0 µg L^?1 with coefficient of determination, r ² ≥ 0.9943. The method showed limits of detection and limits of quantification of all analytes in the range of 0.15–3.0 and 0.5–10.0 µg L^?1, respectively. Good repeatability with RSDs <15% (n = 3) and satisfactory relative recoveries (83.3–111.1%) were obtained for spiked azole antifungal drugs in milk. The results reveal that the developed USAE-D-µ-SPE method was a simple, rapid, efficient, environmentally friendly, and practicable method for the determination of azole antifungals in milk samples.     

Determination of Estrogens in Water Samples by Ionic Liquid-Based Dispersive Liquid-Liquid Microextraction Combined with High Performance Liquid Chromatography

Using 1-hexyl-3-methylimidazolium hexafluorophosphate ([C₆MIM][PF₆]) ionic liquid as extraction solvent, five estrogens including estrone (E₁), 17β-estradiol (E₂), estriol (E₃), 17α -ethynylestradiol (EE₂), and diethylstilbestrol (DES) in water samples were determined by dispersive liquid-liquid microextraction (DLLME) followed by high performance liquid chromatography with a photodiode array detector and a fluorescence detector (HPLC-DAD-FLD). The extraction procedure was induced by the formation of cloudy solution, which was composed of fine drops of [C₆MIM][PF₆] dispersed entirely into the sample solution with the help of a disperser solvent (acetone). Parameters including both extraction and disperser solvents and their volumes, extraction and centrifugal time, sample pH, and salt effect were investigated and optimized. Under the optimized conditions, 110–349 fold enrichment factors of analytes were obtained. The calibration curves were linear in the concentration range of 0.2–100 µg L^?1 for E₂, E₃, and EE₂ detected with FLD, and 1–100 µg L^?1 for E₁ and DES detected with DAD. The correlation coefficient of the calibration curve was between 0.9990 and 0.9997. The limits of detection (LOD, S/N = 3) for the five estrogens were in the range of 0.08–0.5 µg L^?1. The relative standard deviations (RSD) for six replication experiments at the concentration of 5.0 µg L^?1 were ≤5.7%. The proposed method was applied to the analysis of three water samples from different sources (river water, waste water, and sea water). The relative recoveries of spiked water samples are satisfied with 89.3–102.4% and 88.7–105.2% at two different concentration levels of 5.0 and 50.0 µg L^?1, respectively.     

人尿液中麻黄碱和可待因的液-液-液微萃取/高效液相色谱法测定

建立了液-液-液微萃取与高效液相色谱联用技术快速分析尿样中麻黄碱和可待因的方法.优化得到的最佳萃取条件:萃取溶剂为80μL苯,接受相为1.0μL 0.2 mol·L-1的HCI,搅拌速率为80 r·min-1,萃取时间为40 min.在该条件下.获得了高的富集因子(大于117倍).方法的线性范围为麻黄碱0.05-10mg·L-1,可待因0.10-10 mg·L-1,相关系数(r)大于0.997,检出限分别为0.025 mg·L-1和0.05 mg·L-1,相对标准偏差小于9%.该方法能有效地去除尿样中的干扰物质,有机溶剂消耗少,萃取效率高,可同时测定尿样中麻黄碱和可待因.     

基于聚酰胺6纳米纤维膜的固相萃取-高效液相色谱法测定兔血浆中酮康唑对映体

以基于聚酰胺6纳米纤维膜的固相萃取法,结合高效液相色谱手性流动相添加剂法测定了兔血浆中的酮康唑对映体的浓度。仅用1.5mg聚酰胺6纳米纤维膜、100μL甲醇即可完成目标物的富集和洗脱。酮康唑的2个对映体在50.0～400.0μg/L范围内呈良好的线性;方法的定量限为40.0μg/L;日内和日间精密度分别小于6.3%和8.6%;平均绝对回收率为79.4%～85.6%;平均相对回收率为90.0%～96.5%。本方法灵敏、准确、重现性好,符合生物样本中酮康唑对映体分析测定的要求。     

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.     

Directly Suspended Droplet Three Liquid Phase Microextraction of Diclofenac Prior to LC

Directly suspended droplet liquid–liquid–liquid microextraction (LLLME) has been used to determine residues of diclofenac (2-[2-(2,6-dichlorophenyl) aminophenyl] ethanoic acid), in environmental water samples. In this technique a free suspended droplet of an aqueous solvent is delivered to the top-center position of an immiscible organic solvent floating on the top of an aqueous sample while being agitated by a stirring bar placed on the bottom of the sample cell. Recently, diclofenac was found as an environmental contaminant in sewage, surface, ground and drinking water samples. In the present work, diclofenac was extracted from water samples by LLLME and analysed by HPLC with UV detection at 281 nm. Factors such as organic solvent, extraction and back extraction times, stirring rate and the pH of acceptor and donor phases were optimized. Enrichment factor and detection limit (LOD, n = 7) were 102 and 0.1 μg L⁻¹, respectively. The linearity ranged from 0.5 to 2,000 μg⁻¹ with a %RSD (n = 5) of 7.2 at S/N = 3. All experiments were carried out at room temperature (22 ± 0.5 °C).     

快速制备镍钛合金固相微萃取纤维及其与高效液相色谱联用测定环境水样中的紫外线吸收剂

以镍钛合金丝为基体,通过酸处理方法制得具有大比表面积的固相微萃取(SPME)纤维氧化物涂层。将其与高效液相色谱联用,研究了氧化物涂层对芳香分析物的萃取性能。结果表明,该纤维对所选择的紫外线吸收剂具有良好的萃取效率和选择性。进一步优化了紫外线吸收剂2-羟基-4-甲氧基二苯甲酮(BP-3)、2-乙基己基-4-甲氧基肉桂酸酯(EHMC)、4-(二甲氨基)苯甲酸-2-乙基己酯(OD-PABA)和2-乙基己基水杨酸酯(EHS)的萃取条件。方法在0.1~300μg·L~(-1)范围内具有良好的线性关系,检出限为0.025~0.097μg·L~(-1),使用单支SPME纤维同日内和隔日内的精密度分别为4.9%~5.8%和5.5%~6.4%,使用不同批次SPME纤维的精密度为6.3%~7.1%。所建立方法已成功用于环境水样中目标紫外线吸收剂的富集分离和测定。该纤维制作快速简单、稳定性高,不同批次制作的重现性好。