液-液-液微萃取-高效液相色谱法测定人血浆中的局部麻醉剂

建立了液-液-液微萃取与高效液相色谱联用技术同时测定人血浆中3种局部麻醉剂利多卡因、布比卡因和丁卡因的方法。考察了萃取时间、料液pH值和搅拌速度的影响,取佳萃取条件为萃取溶剂为200μL苯,接受相为1.0μL 0.2 mol/L HC l,搅拌速度为250 r/m in,萃取时间为45 m in。在该条件下,获得了高的富集因子(大于305倍)。方法的线性范围为:利多卡因和布比卡因0.025~5 mg/L,丁卡因0.05~5 mg/L,相关系数大于0.996;检出限依次为0.005、0.015和0.025 mg/L;相对标准偏差小于5%。该方法能有效地去除血浆中复杂基体的干扰,萃取效率高,有机溶剂消耗少,是一种有效、灵敏的同时测定血浆中利多卡因、布比卡因和丁卡因的方法。     

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。     

凝固-漂浮分散液液微萃取-高效液相色谱法测定水样中氯酚

采用凝固-漂浮分散液液微萃取(SFO-DLLME)-高效液相色谱法测定水样中3种氯酚.以密度小于水,且凝固点为24 ℃的1-十二醇为萃取剂,甲醇为分散剂,对水样进行分散液液微萃取.将混合液离心,再通过冷冻凝固操作使漂浮的萃取剂和水相分离,萃取剂复溶后进样测定.本实验确定的最佳实验条件为:萃取剂200 μL、分散剂300 μL、1.2 g NaCl、1 mol/L H3PO4 200 μL、样品体积8.0 mL、萃取时间3 min.3种氯酚测定的线性范围为0.05～6.0 mg/L;检出限为20～38 μg/L.应用本方法分析实际水样,加标回收率在90.11%～107.7%之间;日间相对标准偏差在3.5%～4.6%之间.本方法扩展了分散液液微萃取萃取剂的选择范围,具有简便、快速、准确、环境友好等特点.     

液-液-液微萃取/高效液相色谱法测定人血浆中的西地那非和伐地那非

建立了液-液-液微萃取与高效液相色谱联用同时测定血浆中西地那非和伐地那非的方法。考察了萃取溶剂、溶剂体积、接受相液滴大小、搅拌速度和萃取时间等因素对富集因子的影响,得到了萃取溶剂为300 μL 甲苯、接受相为2 μL 0.2 mol/L HCl、搅拌速度为600 r/min和萃取时间为40 min的最佳实验条件。在该条件下,获得了较高的富集因子。两种组分的线性范围均为5 μg/L~1.0 mg/L,加标回收率高于87%,其相对标准偏差小于5%。以信噪比为3计,西地那非的检测限为1 μg/L,伐地那非为0.5 μg/L。该方法能有效地去除复杂基体的干扰,有机溶剂消耗少,萃取效率高,是一种有效的、灵敏的样品前处理方法,适用于血浆中微量西地那非和伐地那非的测定。     

液液萃取-分散液液微萃取-气相色谱-质谱联用测定纺织废水中痕量禁用偶氮染料

建立了液液萃取-分散液液微萃取-气相色谱-质谱联用技术测定纺织废水中痕量偶氮染料的方法。废水中的偶氮染料在碱性条件下经连二亚硫酸钠还原成芳香胺后,先用叔丁基甲醚液液萃取、盐酸反萃进行预浓缩及净化;再以乙腈-氯苯体系进行分散液液微萃取,气相色谱-质谱测定。对前处理条件进行了优化,考察了酸碱度及盐效应对芳香胺萃取效率的影响,结果表明：液液萃取过程中加入30 g NaCl,分散液液微萃取过程中加入1 mL 5 mol/L的NaOH调节体系至碱性才能达到较好的萃取效率。在优化的实验条件下,21种目标物均呈现良好的线性关系,其中13种芳香胺的线性范围为0.05~10 μg/L,7种芳香胺的线性范围为0.05~5 μg/L,2,4-二氨基苯甲醚的线性范围为20~100 μg/L,相关系数为0.996~0.999。20种芳香胺的检出限可达0.05 μg/L,2,4-二氨基苯甲醚检出限为20 μg/L。印染、机织、印花等实际废水加标试验表明,方法的回收率为75.6%~115.1%。该方法富集倍数高,检出限低,适用于纺织废水中痕量禁用偶氮染料的检测。     

液液萃取结合分散固相萃取-液相色谱串联质谱检测食品包装纸中的4-氨基偶氮苯

采用高效液相色谱-串联质谱法（LC-MS/MS）快速测定食品包装纸中偶氮染料释放的4-氨基偶氮苯.试样在0.5 mol/L氢氧化钠溶液的碱性环境下,用连二亚硫酸钠还原试样中的偶氮染料,用甲基叔丁基醚反萃取还原裂解产生的4-氨基偶氮苯,经氮吹、甲醇复溶后,用液相色谱-串联质谱进行测定,内标法定量.方法优化了色谱分离、质谱、液液萃取和分散固相萃取等条件.最优化条件下方法的检出限为0.13 mg/kg,定量限为0.42 mg/kg,加标回收率在90%~95%之间（添加水平分别为1、10、30 mg/kg）,相对标准偏差小于5%.     

液-液-液三相液相微萃取-高效液相色谱法检测尿样中的安非他明和氯胺酮

建立了液-液-液三相液相微萃取与高效液相色谱联用技术测定尿样中的安非他明和氯胺酮的方法。考察了萃取溶剂、料液相pH值、搅拌速度、萃取时间和接受相HCl浓度等因素对富集因子的影响,得到了萃取溶剂为300 μL甲苯,料液相pH值为11,接受相为1.0 μL 0.1 mol/L HCl,搅拌速度为600 r/min,萃取时间为50 min的最佳实验条件。在该条件下,获得了较高的富集因子;方法的线性范围为安非他明0.01～10 μg/mL,氯胺酮0.01～5 μg/mL,相对标准偏差均小于2%,检测限均为5 ng/mL (S/N=3)。建立的三相液相微萃取方法能有效地去除复杂基体的干扰,有机溶剂消耗少,萃取效率高,是一种有效、灵敏的样品前处理方法,适合于尿样中安非他明和氯胺酮的测定。     

微流控液液萃取-液液波导集成化分析系统

利用溴化1-丁基-3-甲基咪唑离子液体/碳酸钠溶液双水相体系,实现了多相层流液液萃取.以具有较高折射率的离子液体为液芯,较低折射率的盐溶液为包层,实现了液液波导吸光度检测.据此建立了一种液液萃取与液液波导检测集成化的微流控分析系统.该系统对甲酚红试样的萃取率在93%以上,对甲酚红试样检测的线性范围为0.01~0.40 mg/m L,相对标准偏差为3.4%(n=11),检出限为3.8μg/m L(3σ).该系统将萃取分离与液液波导长光程吸光度检测集成在一起,为拓展吸光度检测在微流控系统中的应用提供了新思路.     

基于可变亲水性溶剂的液液微萃取-气相色谱-质谱法分析尿中的2′-氯地西泮

建立一种基于可变亲水性溶剂的液液微萃取-气相色谱-质谱联用法,快速检测尿液中2′-氯地西泮。对影响萃取效率的可变亲水性溶剂的种类、用量、转换条件、萃取时间等因素进行考察和优化。在最佳实验条件下,尿液中2′-氯地西泮的线性范围为0. 025~2. 5 mg/L,检出限为0. 007 mg/L,日内和日间回收率为76. 5%~90. 3%,日内和日间精密度为3. 3%~6. 5%。该方法具有良好的线性、检出限、回收率和精密度,有较好的应用价值,可应用于尿液中2′-氯地西泮的分析。     

水中酚类化合物的液-液-液微萃取/ 高效液相色谱联用分析研究

建立了液-液-液微萃取/高效液相色谱联用(LLLME/HPLC)测定环境水中痕量酚类化合物2-甲基苯酚、2-硝基苯酚、2,4-二氯苯酚的分析方法,研究了有机相溶剂种类及其体积、料液相pH值与离子强度、接受相的体积、组成及浓度和搅拌速率、萃取时间等因素对分析物萃取效率的影响。实验结果表明,该方法对酚类化合物的富集倍数可达到404~747倍,方法的线性范围为0.2~300μg/L,RSD(n=6)为6.8%~11.4%。测定加标自来水、江水以及生活污水样品的回收率为83%~110%。     

Improved liquid-liquid-liquid microextraction method and its application to analysis of four phenolic compounds in water samples

An improved liquid-liquid-liquid microextraction (LLLME) technique has been put forward based on the principle of single drop LLLME. In the technique, a vial insert was firstly utilized as acceptor phase container. Because the diameter of the bottom of the vial insert was small, the contact area between the acceptor phase and the vial insert was bigger than that between microsyringe and microdrop of acceptor phase in single drop LLLME, and the stability of microdrop was increased markedly. More acceptor phase could be held in the improved method than that in single drop LLLME, and the sensitivity of the method was increased. The sample vial and vial insert were horizontally placed so that the density of organic solvent has little effect on the selection of organic solvents. Aqueous ammonia and toluene were selected as the acceptor phase and the organic phase, respectively. The improved method was successfully applied to determine four phenolic compounds in real aqueous samples. Good recoveries that ranged from 82.2% to 117.2% were obtained. The intra-day and inter-day reproducibilities (RSD) were under 4.8% and 6.8%, respectively. The extraction efficiency of the improved method was 11-47 times higher than that of single drop LLLME method. The improved LLLME method is economical, rapid, simple, efficient, low organic solvent consumption and no cross-containment. This method is very suitable for the extraction of ionizable and chargeable analyte in complex environmental or biological samples.     

In‐line coupled single drop liquid–liquid–liquid microextraction with capillary electrophoresis for determining fluoroquinolones in water samples

A simple in‐line single drop liquid–liquid–liquid microextraction (SD‐LLLME) coupled with CE for the determination of two fluoroquinolones was developed. The method is capable to quantify trace amount of analytes in water samples and to improve the sensitivity of CE detection. For the SD‐LLLME, a thin layer of organic phase was used to separate a drop of 0.1 M NaOH hanging at the inlet of the capillary from the aqueous donor phase. By this way, the analytes were extracted to the acceptor phase through the organic layer based on their acidic/basic dissociation equilibrium. The drop was immersed into the organic phase during 10 min for extraction and then it is directly injected into the capillary for the analysis. Parameters such as type and volume of organic solvent phase, aqueous donor, and acceptor phases and extraction time and temperature were optimized. The enrichment factor was calculated, resulting 40‐fold for enrofloxacin (ENR) and sixfold for ciprofloxacin (CIP). The linear range were 20–400 μg/L for ENR and 60–400 μg/L for CIP. The detection limits were 10.1 μg/L and 55.3 μg/L for ENR and CIP, respectively, and a good reproducibility was obtained (4.4% for ENR and 5.6% for CIP). Two real water samples were analysed applying the new method and the obtained results presented satisfactory recovery percentages (90–100.3%).     

Liquid–Liquid–Liquid Micro Extraction Combined with CE for the Determination of Rare Earth Elements in Water Samples

A simple method for determination of rare earth elements (REEs) by liquid–liquid–liquid microextraction (LLLME) coupled with capillary electrophoresis and ultraviolet technique was developed. In the LLLME system, 40 mmol L^?1 4-benzoyl-3-methy-1-phenyl-5-pyrazolinone (PMBP) acted as extractant and 4% (v/v) formic acid was used as back-extraction solution. The parameters influencing the LLLME, including the type of the organic solvent, sample pH, formic acid concentration, PMBP concentration, extraction time, volume of organic solvent, stirring rate and phase volume ratio, were investigated. Under the optimized conditions, the detection limits (S/N = 3) of REEs were in the range of 0.19–0.70 ng mL^?1. The developed method was successfully applied to the determination of trace amounts of REEs in water samples.     

Determination of Nitrophenols in Water Using Dynamic Liquid‐Liquid‐Liquid Microextraction under Non‐Equilibrium Consideration

To pursue optimum condition in liquid‐liquid‐liquid microextraction (LLLME), extraction parameters dominating extraction efficiency were investigated by theoretical considerations. The theoretical considerations discussed equilibrium model for equilibrium LLLME and non‐equilibrium model for dynamic LLLME. A method described here is a dynamic LLLME technique combined with high‐performance liquid‐chromatography ultraviolet absorbance detection (HPLC/UV) to determine traces of nitrophenols in water. Analytical parameters such as organic phase, acceptor phase volume, sample agitation, extraction time, acceptor phase NaOH concentration, donor phase HCl concentration, salt addition, and absorption wavelength were identified as variable settings. Relative standard deviation (RSD, 1.8‐4.4%), coefficient of estimation (R², 0.9994‐0.9999), and detection limit (0.032‐0.065 ng mL^?1) were achieved under the variable settings. The proposed method was successfully applied to the analysis of a lake water sample, and the relative recoveries of nitrophenols from spiked water sample were up to 92.5%. The variable settings of LLLME close to optimization was responsible for an acceptable extraction efficiency.     

Orthogonal array designs for the optimization of liquid-liquid-liquid microextraction of nonsteroidal anti-inflammatory drugs combined with high-performance liquid chromatography-ultraviolet detection

Orthogonal array designs (OADs) were applied for the first time to optimize liquid-liquid-liquid microextraction (LLLME) conditions for the analysis of three nonsteroidal anti-inflammatory drug residues (2-(4-chlorophenoxy)-2-methylpropionic acid, ketoprofen, and naproxen) in wastewater samples. Six relevant factors were investigated: type of organic solvent, composition of donor phase and acceptor phase, stirring speed, extraction time and salt concentration. In the first stage, mixed-level orthogonal array design, an OA16 (4(1) x 2(12)) matrix was employed to study the effect of six factors, by which the effect of each factor was estimated using individual contributions as response functions. Based on the results of the first stage, 1-octanol was chosen as organic solvent for extraction. The other five factors were selected for further optimization using an OA16 (4(5)) matrix and a 4 x 4 table to locate more exact levels for each variable. The relative standard deviations for the reproducibility of optimized LLLME varied from 6.2 to 7.1%. The coefficients of determination for calibration curves were higher than 0.9950. The method detection limits for drugs spiked in ultrapure water were in the range of 0.03-0.3 ng/mL. The final optimized conditions were applied to the analysis of drug residues in three wastewater samples in Singapore.     

液相微萃取-毛细管电泳联用对汗液基质中4种芳香胺的同时测定

采用纤维膜三相液相微萃取(HF-LLLME)技术,对汗液基质中的苯胺、邻甲苯胺、对氯苯胺、对硝基苯胺进行了分离富集。以正辛醇为有机相,在供体相pH为9.0,NaCl质量浓度为200g/L,接收相pH为1.0,萃取时间为60min的条件下,4种芳香胺的富集倍数为410～1250倍。将接收相直接进行毛细管电泳(CE)测定,样品相中4种芳香胺的质量浓度在10～100μg/L范围内与电泳峰面积呈良好线性,相关系数均大于0.992,4种芳香胺的检出限为1～10μg/L。运用该法对偶氮染料汗液环境下光致降解过程中产生的苯胺进行测定,回收率为91%～93%,结果满意。     

Determination of methylmercury and phenylmercury in water samples by liquid-liquid-liquid microextraction coupled with capillary electrophoresis

A novel method for determination of methylmercury (MeHg) and phenylmercury (PhHg) by liquid-liquid-liquid microextraction (LLLME) coupled with capillary electrophoresis (CE) with ultraviolet (UV) technique was developed. The method based on MeHg and PhHg was complexed with 1-(2-pyridylazo)-2-naphthol (PAN) to form hydrophobic complexes. When the sample solution was stirred, analytes were extracted into the organic layer (200 microL toluene) and back-extracted simultaneously into the 4.0 microL 0.1% (w/v) l-cysteine microdrop. The factors affecting on the LLLME of two mercury species, including sample pH, complex reagent concentration, extraction time, volume of organic solvent, stirring rate and phase volume ratio, were investigated. Under the optimized conditions, the detection limits (S/N=3) of MeHg and PhHg were 0.94 and 0.43 ngmL(-1) (as Hg), respectively. The precisions (RSDs, c=10 ngmL(-1), n=7) were in the range of 3.3-3.4% for migration time, 6.1-7.2% for peak area response, and 6.7-7.5% for peak height response for the two mercury species. The enrichment factors of 324 for MeHg and 210 for PhHg were obtained with 40 min LLLME. The developed method was successfully applied to the determination of trace amounts of MeHg and PhHg in water samples.     

Single drop liquid-liquid-liquid microextraction of methamphetamine and amphetamine in urine

Single drop liquid-liquid-liquid microextraction (LLLME) combined with high performance liquid chromatography (HPLC)-UV detection was investigated for the determination of a popular drug of abuse, methamphetamine (MAP), and its major metabolite, amphetamine (AP), in urine samples. The target compounds were extracted from NaOH modified sample solution to a thin layer of organic solvent membrane, and back-extracted to an acidic acceptor drop suspended on the tip of a 50-microL HPLC syringe in the aforementioned organic layer. This syringe was also used for direct injection after extraction. Factors affecting extraction efficiency were studied. At optimal conditions, the overall enrichment factor (EF) was 500-fold for AP and 730-fold for MAP, respectively. The method exhibited a wide linear range (1.0-1500 microg/L), low detection limit (0.5 microg/L), and good repeatability (RSD<5.0%) for both analytes. The feasibility of the method was demonstrated by the analysis of human urine samples.     

Hollow fiber-based liquid–liquid–liquid microextraction combined with electrospray ionization-ion mobility spectrometry for the determination of pentazocine in biological samples

A new method based on liquid–liquid–liquid microextraction combined with electrospray ionization-ion mobility spectrometry (LLLME-ESI-IMS) was used for the determination of pentazocine in urine and plasma samples. Experimental parameters which control the performance of LLLME, such as selection of composition of donor and acceptor phase, type of organic solvent, ionic strength of the sample, extraction temperature and extraction time were studied. The limit of detection and relative standard deviation of the method were 2 ng/mL and 5.3%, respectively. The linear calibration ranged from 10 to 500 ng/mL with r² = 0.998. Pentazocine was successfully determined in urine and plasma samples without any significant matrix effect.