分散液相微萃取技术研究进展

分散液相微萃取是最近发展起来的一种新型样品前处理技术,该方法操作简单、成本低、富集效率高、所需有机溶剂用量极少,是一种环境友好的液相微萃取新技术.与悬滴液相微萃取和中空纤维液相微萃取相比,萃取时间大为缩短.分散液相微萃取可与气相色谱、液相色谱和原子吸收分光光度计等仪器联用,并已在环境样品、食品样品分析中得到了较广泛的应用.本文对分散液相微萃取的基本原理、影响富集效率的因素和目前的应用研究进展进行了评述.     

液相微萃取研究与应用

液相微萃取是近年来新兴的一种微型化样品前处理技术。该技术集萃取、净化、浓缩于一体,具有溶剂耗量少、成本低廉、操作便捷、精确和灵敏度高的特点。本文全面深入地综述了液相微萃取的各种工作模式及其原理和特点,阐述了相关的联用分析技术和方法的适用性,归纳和分析了影响萃取的主要影响因素及优化的方法,突出了上述几方面中具有发展潜力的新进展,包括各种动态萃取模式与装置、 与其它技术联用的新策略、离子液体作为萃取溶剂等,详细总结了近年来液相微萃取技术在环境、药物和食品等分析领域中的应用情况。     

悬浮固化液相微萃取技术研究进展

悬浮固化液相微萃取集采样、萃取、浓缩于一体,具有富集效率高、成本低、有机溶剂用量少,易与气相色谱(GC)、高效液相色谱(HPLC)、原子吸收分光光度仪(AAS)联用等特点,是一种环境友好的样品前处理新技术.本文对悬浮固化液相微萃取的基本原理、影响萃取率的因素和目前的应用研究进展进行了简要评述.     

液相微萃取技术的研究进展

液相微萃取是近年来发展起来的一种新型的样品前处理技术,该技术集采样、萃取和浓缩于一体,需要有机溶剂量非常少,是一种环境友好的萃取技术,在国内尚未广泛应用。本文综述了液相微萃取的方式、原理、影响因素和应用,引用文献30篇。     

液相微萃取技术在药物分析中的应用

液相微萃取(LPME)技术是上世纪90年代发展起来的一种新型微型化样品前处理技术,它集采样、纯化、富集于一体,减少了常规液-液萃取过程中有机溶剂的使用量,具有操作简单、模式灵活多样、成本低廉、富集效率高、环境友好等优点.本文系统综述了LPME技术的各种模式、原理及其在药物分析中近三年的应用现状,并展望了其发展方向.     

悬浮固化分散液液微萃取技术的发展及应用进展

综述了悬浮固化分散液液微萃取技术的发展,及其在水、食品和生物样品分析中的应用进展,并对其前景作了简要展望(引用文献67篇)。     

多孔中空纤维液相微萃取技术的研究进展

基于多孔中空纤维的液相微萃取集采样、萃取和浓缩于一体,具有成本低,易与多种分析仪器联用等特点,该技术不仅可得到较高的富集倍数和回收率,而且具有突出的样品净化功能,有机溶剂用量非常少,是一种环境友好的样品前处理新技术,国内尚未广泛应用。本文综述了多孔中空纤维液相微萃取的主要装置、萃取模式、影响因素及其应用,引用文献54篇。     

分散液液微萃取技术的研究进展

分散液液微萃取是一种基于传统液液萃取的新型样品前处理技术。该文以分散液液微萃取技术中萃取剂的筛选为出发点,综述了低密度萃取剂、辅助萃取剂、反萃取剂和离子液体等低毒性萃取剂在该技术中的应用,以及应用自制装置、溶剂去乳化、悬浮萃取剂固化,辅助萃取,反萃取和离子液体-分散液液微萃取等萃取模式;并简要评述了该技术与液液萃取、固相萃取、固相微萃取、分散固相萃取、基质固相分散萃取、超临界流体萃取、超声辅助萃取等其他样品前处理技术的联用特性。     

分散液液微萃取技术及其在生物样品分析中的研究进展

分散液液微萃取是一种新型微萃取技术,具有易操作、低成本、耗时短、环境友好、萃取效率高等优点。该文着眼于分散液液微萃取技术中萃取剂的性质及辅助分散方式,综述了常规分散液液微萃取、离子液体分散液液微萃取、超声辅助分散液液微萃取等多种萃取模式,并重点归纳总结了近5年分散液液微萃取技术在生物样品分析领域的应用进展。     

超声辅助分散液-液微萃取/高效液相色谱联用富集分析环境水样中邻苯二甲酸酯类化合物

建立了超声波辅助分散液-液微萃取(DLLME)与高效液相色谱(HPLC)联用对环境水样中痕量邻苯二甲酸二甲酯(DMP)、邻苯二甲酸二乙酯(DEP)、邻苯二甲酸二丁酯(DBP)、邻苯二甲酸二(2-乙基己基)酯(DEHP)和邻苯二甲酸二辛酯(DOP)富集分离测定的方法,优化了色谱分离条件,考察了萃取剂与分散剂的种类与用量、萃取时间和离子强度对超声辅助DLLME/HPLC的影响。在优化实验条件下,邻苯二甲酸酯色谱峰面积与其浓度在1.00～100μg.L-1范围内呈良好的线性关系,相关系数均大于0.996,平均加标回收率为91%～103%,相对标准偏差(RSDs,n=5)为2.0%～6.8%,5种邻苯二甲酸酯类化合物的检出限(S/N=3)分别为0.08、0.04、0.03、0.01、0.07μg.L-1。建立的方法用于环境水样中邻苯二甲酸酯的测定,平均加标回收率为85%～119%,RSDs(n=3)为2.3%～11.1%。该方法适用于环境水样中痕量邻苯二甲酸酯类化合物的富集分析。     

分散液液微萃取-反相液液微萃取-扫集-胶束电动色谱法测定红酒中的3种氯酚类物质

建立了分散液液微萃取（DLLME）-反相液液微萃取（RP-LLME）-扫集-胶束电动色谱富集模型,并用于红酒中五氯酚（PCP）、2,4,6-三氯酚（TCP）和2,4-二氯酚（DCP）3种氯酚的测定。实验考察了两步微萃取的萃取参数对氯酚萃取率的影响和样品分离富集的电泳条件。最佳萃取条件DLLME为：3.5 mL红酒（pH 3.0,120 g/L NaCl）,300 μL正己烷（萃取剂）;RP-LLME为：25 μL 0.16 mol/L NaOH（萃取剂）。最佳电泳条件：25 mmol/L NaH₂PO₄,100 mmol/L十二烷基硫酸钠（SDS）,30%（v/v）乙腈,pH 2.3;分离电压-15 kV;样品基质为80 mmol/L NaH₂PO₄;压力进样20 s×20.67 kPa（3 psi）。PCP和TCP的线性范围为0.5~100 μg/L（r≥0.9910）,DCP的线性范围为1.5~80 μg/L（r=0.9851）。3种分析物的检出限（S/N=3）为0.035~0.114 μg/L,加标回收率为75.2%~104.7%,相对标准偏差≤6.17%。该方法富集倍数高、灵敏度高、重现性好、分析速度快,可为不同样品基质中痕量氯酚污染物及某些弱酸性有机污染物测定提供参考。     

Recent trends in replacement of disperser solvent in dispersive liquid-liquid microextraction methods

Since its innovation in 2006, the dispersive liquid-liquid microextraction (DLLME) method has attracted the attention of analytical chemists in the field of sample preparation. This method has been successfully applied to determine trace amounts of pollutants in various matrices, but the restriction in the choice of suitable disperser and extraction solvents, and high disperser solvent consumption leading to decreased partition coefficients of the analytes between aqueous phase and extractant are its problems. To solve these drawbacks and develop environmentally friendly techniques, various alternatives for the conventional DLLME have been presented. The current review will begin with an introduction to the sample preparation, implementation of DLLME, and its advantages. Then, we focus on its drawbacks, which result mainly from the use of disperser solvent. Afterward, some of the most interesting approaches that have been employed and published until now are reviewed. Finally, an outlook on the future of these techniques will be given.     

A novel, environmentally friendly dispersive liquid-liquid microextraction procedure for the determination of copper

A novel, simple and environmentally friendly procedure for copper determination has been developed. The method is based on the formation of an ion associate of Cu(I) with 1,3,3-trimethyl-2-[5-(1,3,3-trimethyl-1,3-dihydroindol-2-ylidene)-penta-1,3-dienyl]-3H-indolium (DIDC) in the presence of chloride ions as ligand, followed by dispersive liquid-liquid microextraction (DLLME) of the formed ion associate into organic phase and UV-Vis spectrophotometric detection. The following experimental conditions were used: pH 3, 0.24 mol L^− 1 chloride ions, 0.06 mmol L^− 1 DIDC. The effect of the nature of the extraction solvent, auxiliary solvent and disperser solvent used was studied. A mixture of amyl acetate, tetrachloromethane, and methanol in a 1:1:3 v/v/v ratio was selected for the DLLME procedure. The absorbance of the coloured extracts at 640 nm wavelength obeys Beer's law in the range 0.020-0.090 mg L^− 1 of Cu. The limit of detection calculated from a blank test (n = 10) based on 3s is 0.005 mg L^− 1 of Cu. The developed procedure was applied to the analysis of water samples. The suggested DLLME is compared with two procedures previously reported from our laboratory based on (1) conventional liquid-liquid extraction, and (2) sequential injection extraction performed in a dual-valve sequential injection system. The advantages and disadvantages of each method are discussed.     

分散液液微萃取/气相色谱-质谱法测定蜂蜜中六六六和滴滴涕类农药残留

建立了分散液液微萃取(DLLME)与气相色谱-质谱法(GC-MS)联用快速检测蜂蜜中六六六(BHC)和滴滴涕(DDT)类农药残留的分析方法.使用三氯甲烷为萃取剂,通过涡旋、离心使分析物富集到微量三氯甲烷中,采用气相色谱-质谱进行分析.实验对影响DLLME萃取效率的因素,如萃取剂种类和体积、分散剂种类和体积、萃取时间等进行了考察,同时对方法的基质效应和性能进行了评估.结果显示:由于基质效应,8种六六六和滴滴涕类农药都出现信号增强现象.8种六六六和滴滴涕类农药在2~500 μg/L范围内线性关系良好,相关系数(r²)为0.991~0.998,方法富集倍数为74~96;当试样的加标水平为20、50和100 μg/kg时,8种六六六和滴滴涕类农药的回收率为61.0%~100.1%,相对标准偏差(RSD, n=5)为2.2%~19.5%.8种六六六和滴滴涕类农药的最低检测浓度均为20 μg/kg,最小检出量皆为1.0 ng.该方法简单、快速、高效,适用于蜂蜜中六六六和滴滴涕类农药的残留检测.     

Part-per-trillion determination of chlorobenzenes in water using dispersive liquid-liquid microextraction combined gas chromatography-electron capture detection

In this study, a simple, rapid and efficient method, dispersive liquid-liquid microextraction (DLLME) combined gas chromatography-electron capture detection (GC-ECD), for the determination of chlorobenzenes (CBs) in water samples, has been described. This method involves the use of an appropriate mixture of extraction solvent (9.5 μl chlorobenzene) and disperser solvent (0.50 ml acetone) for the formation of cloudy solution in 5.00 ml aqueous sample containing analytes. After extraction, phase separation was performed by centrifugation and the enriched analytes in sedimented phase were determined by gas chromatography-electron capture detection (GC-ECD). Our simple conditions were conducted at room temperature with no stiring and no salt addition in order to minimize sample preparation steps. Parameters such as the kind and volume of extraction solvent, the kind and volume of disperser solvent, extraction time and salt effect, were studied and optimized. The method exhibited enrichment factors and recoveries ranging from 711 to 813 and 71.1 to 81.3%, respectively, within very short extraction time. The linearity of the method ranged from 0.05 to 100 μg l⁻¹ for dichlorobenzene isomers (DCB), 0.002-20 μg l⁻¹ for trichlorobenzene (TCB) and tetrachlorobenzene (TeCB) isomers and from 0.001 to 4 μg l⁻¹ for pentachlorobenzene (PeCB) and hexachlorobenzene (HCB). The limit of detection was in the low μg l⁻¹ level, ranging between 0.0005 and 0.05 μg l⁻¹. The relative standard deviations (R.S.D.s) for the concentration of DCB isomers, 5.00 μg l⁻¹, TCB and TeCB isomers, 0.500 μg l⁻¹, PeCB and HCB 0.100 μg l⁻¹ in water by using the internal standard were in the range of 0.52-2.8% (n = 5) and without the internal standard were in the range of 4.6-6.0% (n = 5). The relative recoveries of spiked CBs at different levels of chlorobenzene isomers in tap, well and river water samples were 109-121%, 105-113% and 87-120%, respectively. It is concluded that this method can be successfully applied for the determination of CBs in tap, river and well water samples.     

分散液液微萃取-在线衍生化-气相色谱-质谱联用法检测环境水样品中紫外吸收剂

建立了分散液液微萃取（dispersive liquid-liquid microextraction,DLLME）-在线衍生化-气相色谱-质谱（GC-MS）方法,将其用于环境水中6种二苯甲酮类紫外吸收剂（BPs）（二苯甲酮、2,4-二羟基二苯甲酮、2-羟基-4-甲氧基二苯甲酮、4-羟基二苯甲酮、2-羟基-4-辛氧基二苯甲酮、2,2'-二羟基-4,4'-二甲氧基二苯甲酮）的检测。系统优化了在线衍生化的条件（如进样口温度、不分流时间、衍生化试剂用量）以及DLLME萃取条件（如萃取剂种类、分散剂种类、萃取剂与分散剂比例、样品体积、样品溶液离子强度及pH值）等。在最优的条件下,所考察的6种BPs检出限为0.011~0.15 μg/L,重现性（RSD）为0.7%~16.6%。该方法结果准确可靠,操作简单,富集效果好,成本较低,环境友好,在实际样品检测中具有一定的应用前景。     

Dispersive liquid-liquid microextraction followed by high-performance liquid chromatography as an efficient and sensitive technique for simultaneous determination of chloramphenicol and thiamphenicol in honey

Dispersive liquid-liquid microextraction (DLLME) coupled with high-performance liquid chromatography-variable wavelength detector (HPLC-VWD) was developed for extraction and determination of chloramphenicol (CAP) and thiamphenicol (THA) in honey. In this extraction method, 1.0 mL of acetonitrile (as dispersive solvent) containing 30 μL 1,1,2,2-tetrachloroethane (as extraction solution) was rapidly injected by syringe into a 5.00-mL water sample containing the analytes, thereby forming a cloudy solution. After extraction, phase separation was performed by centrifugation and the enriched analytes in the sedimented phase were determined by HPLC-VWD. Some important parameters, such as the nature and volume of extraction solvent and dispersive solvent, extraction time, sample solution pH, sample volume and salt effect were investigated and optimized. Under the optimum extraction condition, the method yields a linear calibration curve in the concentration range from 3 to 2000 μg kg⁻¹ for target analytes. The enrichment factors for CAP and THA were 68.2 and 87.9, and the limits of detection (S/N = 3) were 0.6 and 0.1 μg kg⁻¹, respectively. The relative standard deviations (RSDs) for the extraction of 10 μg kg⁻¹ of CAP and THA were 4.3% and 6.2% (n = 6). The main advantages of DLLME-HPLC method are simplicity of operation, rapidity, low cost, high enrichment factor, high recovery, good repeatability and extraction solvent volume at microliter level. Honey samples were successfully analyzed using the proposed method.     

Determination of phenylurea herbicides in aqueous samples using partitioned dispersive liquid-liquid microextraction

Partitioned dispersive liquid-liquid microextraction (PDLLME), using THF as the dispersive solvent and dichloromethane as the extraction solvent, was utilized to isolate and concentrate phenylurea herbicides (PUHs) from aqueous samples. In PDLLME, a dispersive solvent should be able to partition in the organic extractant droplets to effectively extract the polar organic compounds from aqueous samples. The mixture of the water-immiscible extractant and the partitioned dispersive solvent was obtained by centrifugation, dried under low pressure, reconstituted in methanol-water mixture (1:1), and injected into a HPLC system for the determination of PUHs. The enrichment factors of the PUHs ranged from 68 to 126 under the optimal conditions. The linear range was 0.5-100 ng ml⁻¹ for each analyte, the relative standard deviations of PUHs were in the range of 1.5-5.9% (n = 5), and the detection limits (signal-to-noise ratio of 3) ranged from 0.10 to 0.28 ng ml⁻¹ for the herbicides. The range of intraday precision (n = 5) for PUHs at the levels of 0.5, 5, and 50 ng ml⁻¹ were 3.0-5.9%, 1.8-3.3%, and 2.2-3.6%, respectively. The range of interday precision (n = 5) at 0.5, 5, and 50 ng ml⁻¹ were 0.4-1.8%, 1.2-2.4%, and 0.9-2.3%, respectively. The recoveries of PUHs from three spiked river water samples, at a level of 10 ng ml⁻¹, were 91.2-104.1%. Due to its rapidity, ease of operation, and high recovery, PDLLME can be utilized to isolate and concentrate organic environmental contaminants such as PUHs from aqueous samples.     

A dispersive liquid-liquid microextraction procedure for determination of boron in water after ultrasound-assisted conversion to tetrafluoroborate

A novel, simple and green procedure is presented for the determination of boron. The method is based on ultrasound-assisted conversion of boron to tetrafluoroborate anion and the formation of an ion pair between BF₄⁻ and Astra Phloxine reagent (R), followed by dispersive liquid-liquid microextraction of the ion pair formed and subsequent UV-vis spectrophotometric detection. The conversion of boron to tetrafluoroborate anion is performed in an acidic medium of 0.9 mol L⁻¹ H₂SO₄ in the presence of 0.1 mol L⁻¹ F^- by means of 10 min of ultrasonication. The extraction of the ion pair formed between BF₄⁻ and R (1 × 10⁻⁴ mol L⁻¹ R) is carried out by dispersive liquid-liquid microextraction using 0.5 mL of amyl acetate (as extraction solvent), tetrachloromethane (as auxiliary solvent) and acetonitrile (as dispersive solvent) in a ratio of 1:1:2. The absorbance of the coloured extracts obeys Beer's law in the range 0.22-18.7 mg L⁻¹ of B(III) at 553 nm wavelength. The limit of detection calculated from a blank test (n = 10) based on 3 s is 0.015 mg L⁻¹ of B(III). The method was applied to the determination of boron in mineral waters.