Chiral Nano-Liquid Chromatography and Dispersive Liquid-Liquid Microextraction Applied to the Analysis of Antifungal Drugs in Milk

A novel chromatographic application in chiral separation by using the nano-LC technique is here reported. The chiral recognition of 12 antifungal drugs was obtained through a 75 µm I.D. fused-silica capillary, which was packed with a CSP-cellulose 3,5-dichlorophenylcarbamate (CDCPC), by means of a lab-made slurry packing procedure. The mobile phase composition and the experimental conditions were optimized in order to find the optimum chiral separation for some selected racemic mixtures of imidazole and triazole derivatives. Some important parameters, such as retention faction, enantioresolution, peak efficiency, and peak shape, were investigated as a function of the mobile phase (pH, water content, type and concentration of both the buffer and the organic modifier, and solvent dilution composition). Within one run lasting 25 min, at a flow rate of approximately 400 nL min⁻¹, eight couples of enantiomers were baseline-resolved and four of them were separated in less than 25 min. The method was then applied to milk samples, which were pretreated using a classical dispersive liquid–liquid microextraction technique preceded by protein precipitation. Finally, the DLLME-nano-LC–UV method was validated in a matrix following the main FDA guidelines for bioanalytical methods.     

Simultaneous Dispersive Liquid–Liquid Microextraction and Determination of Different Polycyclic Aromatic Hydrocarbons in Surface Water

Polycyclic aromatic hydrocarbons (PAHs) are a class of persistent organic pollutants of water, and their determination at trace levels in the aquatic ecosystems is essential. In this work, an ultrasound-assisted dispersive liquid–liquid microextraction (DLLME) procedure was suggested utilizing a binary dispersive agent for recovery of different molecular weight polycyclic aromatic hydrocarbons (PAHs) from waters. The detection was carried out by gas chromatography–mass spectrometry (GC-MS) as well as high-performance liquid chromatography with fluorescence and diode-array detection (HPLC-FD/PDA). The method was optimized for the extraction of analytes with respect to the mixture composition, ratios of components, ultrasonication time and centrifugation parameters. The analytical schemes for PAHs extraction from water samples using different ratios of extraction and dispersive solvents are reported. The mixture consisting of chloroform and methanol was applied for the extraction of PAHs containing two or three fused aromatic rings; the mixture of chloroform and acetonitrile is suitable for PAHs containing more than four aromatic rings. The mixture of chloroform:acetone + acetonitrile was applied in the universal scheme and allowed for the simultaneous extraction of 20 PAHs with different structures. The developed sample preparation schemes were combined with GC-MS and HPLC-FD/PDA, which allowed us to determine the analytes at low concentrations (from 0.0002 µg/L) with the recoveries exceeding 80% and relative standard deviations of about 8%. The developed methods for the determination of 20 PAHs were applied to the analysis of water samples from the Karasun Lake (Krasnodar), Azov Sea (Temryuk) and Black Sea (Sochi).     

Determination of Ultra-Trace Cobalt in Water Samples Using Dispersive Liquid-Liquid Microextraction Followed by Graphite Furnace Atomic Absorption Spectrometry

A novel method for the determination of ultra-trace cobalt by dispersive liquid–liquid microextraction (DLLME) coupled with graphite furnace atomic absorption spectrometry has been developed. It is based on the color reaction of Co²⁺ with 2-(5-bromo-2-pyridylazo)-5-dimethylaminoaniline (5-Br-PADMA) in a Britton–Robinson buffer solution at pH 6.0 to form stable hydrophobic chelates, which were separated and enriched by DLLME with 1,2-dichloroethane (CH₂ClCH₂Cl) as extraction and acetonitrile (CH₃CN) as a dispersive solvent. The sedimented phase containing the chelates is then determined with GFAAS. Parameters that affect extraction efficiency, such as types and volumes of extraction and disperser solvents, pH of sample solution, extraction time, concentration of the chelating agent 5-Br-PADMA, and salt effect, were investigated. Under optimal conditions, the calibration graph was linear over the range 0.05–1.0 ng/mL, with a correlation coefficient of 0.9922 and a detection limit of 0.03 ng/mL. Preconcentration factor (PF) is calculated as the ratio of the aqueous solution volume (5 mL) to that of the organic phase volume (40 μL), and enrichment factor (EF) is calculated as the ratio of the slopes of the calibration graphs obtained with and without DLLME for 5.0 mL of sample solution, which were 120 and 112.5, respectively. The extraction efficiency, calculated by EF/PF·100, was 93.8%. The relative standard deviation (RSD) at the 0.5 ng/mL Co²⁺ level was 3.8% (n = 6). The method has been applied to the determination of trace cobalt in water samples with satisfactory results.     

Application of a Liquid-Liquid Microextraction Method Based on a Natural Hydrophobic Deep Eutectic Solvent for the Extraction of Plastic Migrants from Kombuchas

A vortex-assisted liquid-liquid microextraction, based on a natural hydrophobic deep eutectic solvent made from the monoterpene thymol and octanoic fatty acid, was employed for the analysis of 11 phthalate esters and one adipate in kombucha (a tea-based fermented beverage). Separation and determination were performed using an ultra-high performance liquid chromatography (UHPLC) system coupled to a single quadrupole mass spectrometer. Confirmatory analyses were carried out through UHPLC tandem mass spectrometry. The full method was validated in terms of matrix effect, matrix-matched calibration, sensitivity, recovery, limits of detection and quantification and repeatability. Satisfactory determination coefficients for quadratic calibration curves (≥0.9938), recovery values (67–120%) and limits of detection (0.07–5.45 µg/L) were obtained. Analysis of 26 kombucha samples reported concentrations for dibutyl phthalate and dimethyl phthalate in the range between the limit of quantification (LOQ) and 16.18 ± 1.14 µg/L, although these phthalates were also detected under the LOQ in some of the analyzed samples. Only one of the samples bottled in plastic containers (7) did not present residues while only five of the 19 samples in glass bottles contained any plasticizer. However, the highest concentration was found in a kombucha bottled in food-grade glass. This work represents the first application in which phthalates and adipates are analyzed in kombuchas.     

Application of a Low Transition Temperature Mixture for the Dispersive Liquid–Liquid Microextraction of Illicit Drugs from Urine Samples

The use of psychoactive substances is a serious problem in today’s society and reliable methods of analysis are necessary to confirm their occurrence in biological matrices. In this work, a green sample preparation technique prior to HPLC-MS analysis was successfully applied to the extraction of 14 illicit drugs from urine samples. The isolation procedure was a dispersive liquid–liquid microextraction based on the use of a low transition temperature mixture (LTTM), composed of choline chloride and sesamol in a molar ratio 1:3 as the extracting solvent. This mixture was classified as LTTM after a thorough investigation carried out by FTIR and DSC, which recorded a glass transition temperature at −71 °C. The extraction procedure was optimized and validated according to the main Food and Drug Administration (FDA) guidelines for bioanalytical methods, obtaining good figures of merit for all parameters: the estimated lower limit of quantitation (LLOQ) values were between 0.01 µg L⁻¹ (bk-MMBDB) and 0.37 µg L⁻¹ (PMA); recoveries, evaluated at very low spike levels (in the ng-µg L⁻¹ range), spanned from 55% (MBDB) to 100% (bk-MMBDB and MDPV); finally, both within-run and between-run precisions were lower than 20% (LLOQ) and 15% (10xLLOQ).     

分散液-液微萃取技术在污染物分析中的应用

分散液-液微萃取技术是一种新型的、具有巨大潜力的样品前处理技术,已经越来越多地被应用到多种污染物的富集过程中。此方法具有简单、快速、价格低廉、环境友好、回收率和富集倍数高等优点。近年来,作为一种可行的分析技术,分散液-液微萃取技术获得了持续的关注和广泛应用。该文综述了分散液-液微萃取技术的研究进展及其在不同介质污染物分析中的应用。     

分散液液微萃取技术在食品分析中的应用进展

近年来,分散液液微萃取作为一种新型液相微萃取(LPME)技术受到广泛关注。该技术具有操作简单、有机溶剂用量少、富集倍数高等显著优点,已被广泛用于各类样品基质中无机和有机分析物的提取。但由于传统分散液液微萃取技术的萃取剂以高毒性有机溶剂为主,且选择性差,从而严重限制了该技术的应用。为此,最近几年发展了许多操作模式,如低密度萃取剂分散液液微萃取、悬浮固化分散液液微萃取、调节萃取剂密度的分散液液微萃取、离子液体-分散液液微萃取、水溶液作为萃取剂的反相分散液液微萃取等。该文综述了分散液液微萃取技术原理、萃取过程和影响因素(如萃取剂与分散剂种类和体积、p H值、离子强度、萃取时间等),并对其在食品分析中的应用进展进行了系统总结。     

分散液液微萃取-气相色谱法测定水样中甲拌磷农药

建立了基于分散液液微萃取(DLLME)的新型样品前处理方法,并采用气相色谱/氢火焰离子化检测器对水样中痕量的甲拌磷农药进行了测定。考察了影响分散液液微萃取的因素包括萃取溶剂、分散剂、样品体积、萃取温度和离心速度等。在最佳实验条件下,对甲拌磷的富集倍数达到300倍;检出限为0.001μL/L;方法的线性范围为0.01~10μL/L,R2为0.9986;相对标准偏差为6.65%;回收率为104%。将分散液液微萃取法与单滴液相微萃取和离子液体-液相微萃取方法进行了对比,结果表明,分散液液微萃取技术具有操作简单、快捷(前处理时间小于5 min)、富集效果好、回收率高等优点。同时预言,将离子液体与分散液液微萃取结合,将会产生更加满意的结果。     

分散液液微萃取-气相色谱法快速测定水中23种有机磷农药

建立了分散液液微萃取(DLLME)的新型样品前处理方法,并采用气相色谱/火焰光度检测器对饮用水中的治螟磷、甲拌磷、二嗪农、乙拌磷、甲基毒死蜱、甲基对硫磷、皮蝇磷、杀螟松、马拉硫磷、毒死蜱、倍硫磷、对硫磷、溴硫磷、嘧啶磷、甲基异硫磷、稻丰散、杀扑磷、丙溴磷、乙硫磷、三唑磷、三硫磷、哒嗪硫磷、亚胺硫磷23种痕量有机磷农药残...     

超声辅助分散液液微萃取-高效液相色谱法快速测定水样中的6种农药

为实现小体积环境水祥中不同农药的准确、快速、高灵敏测定,通过研究萃取剂、分散剂的种类、体积、盐浓度及超声时间对萃取效率的影响,结合分散液液微萃取与超声萃取技术,并与高效液相色谱联用,建立了快速测定环境水样中的吡虫啉、水胺硫磷、辛硫磷、毒死蜱、哒螨灵和阿维菌素6种农药的方法.在优化的萃取条件下,检测6种农药的线性范围为10～ 600 μg/L,检出限(S/N=3)为0.8～3.1 μg/L,相对标准偏差为4.7％～11.3％,富集倍数可达到58～187倍.本方法具有良好的线性、精密度和回收率,并具有较好的实用性.     

离子液体分散液液微萃取/高效液相色谱法测定环境水样中7种萘二酚

建立了测定环境水样中7种萘二酚的离子液体分散液液微萃取/高效液相色谱(IL-DLLME-HPLC)分析方法。以1-丁基-3-甲基咪唑六氟磷酸盐([C4MIM][PF6])为萃取剂,水样体积为8.0 m L,研究了萃取剂用量、水相p H值、萃取时间及盐添加量对7种萘二酚萃取效率的影响。获得最佳萃取条件为:[C4MIM][PF6]体积为150μL,水相p H值为5.0~7.0,涡旋萃取时间为3 min,氯化钠添加量为0.20 g/m L。在优化条件下,7种萘二酚在一定质量浓度范围内线性关系良好,相关系数均不小于0.997 7;方法富集倍数为57倍,方法检出限(S/N=3)为0.3~1.0μg/L;阴性环境水样中3个加标水平的平均回收率为83.5%~103%,相对标准偏差(n=6)为1.1%~3.8%。该方法快速简单、准确灵敏、环保,适用于环境水样中痕量萘二酚的富集检测。     

衍生-分散液相微萃取/气相色谱-质谱法测定纺织品中的含氯酚及邻苯基苯酚

建立了衍生、分散液相微萃取(DLLME)与气相色谱-质谱(GC-MS)联用测定纺织品中5种含氯酚(PCPs)和邻苯基苯酚(OPP)的方法。对影响萃取和富集效率的因素,萃取剂种类及用量、分散剂种类及用量、碳酸钾溶液浓度等条件进行了优化。确定最佳实验条件为:纺织样品用0.15 mol/L的碳酸钾溶液超声提取后定容,取5 mL溶液,加入0.1 mL乙酸酐进行衍生处理2 min后,经0.2 mL四氯化碳(萃取剂)与0.6mL异丙醇(分散剂)混合溶液分散萃取,在4 000 r/min下离心3 min,取下层有机相进行GC-MS分析。在优化实验条件下,5种含氯酚和邻苯基苯酚的线性范围为0.001~1 mg/L,相关系数为0.999 1~0.999 9,检出限(S/N=3)为0.5~5μg/kg,样品加标回收率为87.2%~103.7%,相对标准偏差为2.5%~4.8%。方法简单、灵敏,回收率和重复性良好,可用于纺织品中5种含氯酚和邻苯基苯酚的测定。     

温度驱动离子液体分散微萃取/超高压液相色谱检测水样中的微量四环素

建立了一种超高压液相色谱(UPLC)快速测定环境水样中8种痕量四环素的方法.利用稀土金属镧作为螯合试剂与水样中的四环素形成疏水性螯合物.温度驱动[Bmim]PF6分散萃取富集目标物,采用超高压液相色谱进行分离,紫外检测器检测,并对实验条件进行了优化.在最佳条件下,8种四环素在一定质量浓度范围内呈良好线性,r2均大于0....     

Application of liquid–liquid microextraction for the effective separation and simultaneous determination of 11 pharmaceuticals in wastewater samples using high‐performance liquid chromatography with tandem mass spectrometry

A dispersive liquid–liquid microextraction method for the simultaneous determination of 11 pharmaceuticals has been developed. The method is based on a microextraction procedure applied to wastewater samples from different regions of Hungary followed by high‐performance liquid chromatography with mass spectrometry. The effect of the nature of the extractant, dispersive solvent, different additives, and extraction time were examined on the extraction efficiently of the dispersive liquid–liquid microextraction method. Under optimal conditions, the linearity for determining the pharmaceuticals was in the range of 1–500 ng/mL, with the correlation coefficients ranging from 0.9922 to 0.9995. The limits of detection and limits of quantification were in the range of 0.31–6.65 and 0.93–22.18 ng/mL, respectively.     

苄基功能化离子液体对有机磷和苯环化合物的分散液-液微萃取性能研究

以苄基功能化的离子液体1-苄基-3-甲基咪唑双三氟甲烷磺酰亚胺(1-Benzyl-3-methylimidazolium bis [(trifluoromethyl)sulfonyl]imide,[BeMIM][Tf2 N])作为分散液-液微萃取的萃取剂,与高效液相色谱联用,用于环境水样中5种有机磷农药(辛硫磷、杀螟松、毒死蜱、甲拌磷和对硫磷)以及2种苯环化合物(氯化萘和蒽)的萃取与富集。并与其它离子液体([OMIM][Tf2 N])以及普通有机溶剂(CCl4和 C2 Cl4)的萃取效能进行了对比。萃取优化条件为：40μL [BeMIM][Tf2 N]作为萃取剂,1 mL 甲醇作为分散剂,离心时间5 min,样品溶液中不添加盐。在优化的条件下,本方法的线性关系良好(R2=0.9994~0.9998);对10,40和100μg/ L 不同添加浓度重复测定5次的日内和日间 RSD 分别为1.1%~4.3%和0.8%~4.8%,LOD 为0.01~1.0μg/ L (S/ N=3)。将本方法用于3种实际水样中目标分析物的测定,加标回收率和 RSD 分别为82.7%~118.3%和0.7%~5.6%。由于在咪唑环上引入了苄基基团,[BeMIM][Tf2 N]与目标分析物之间除存在疏水作用外,还存在π-π作用,故对目标物的萃取效率明显提高,富集倍数和回收率分别高达339和81.4%。测定了分析物在[BeMIM][Tf2 N]-DLLME 体系中的分配系数,对萃取机制进行初步探讨。     

分散固相萃取-分散液液微萃取/气相色谱-串联质谱法测定蔬菜中19种有机磷农药残留

采用分散固相萃取和分散液液微萃取联用方法,建立了气相色谱-串联质谱法(GC-MS/MS)同时测定蔬菜中19种有机磷农药残留量的分析方法。分散固相萃取方法以乙腈为萃取液,以N-丙基-乙二胺(PSA)和C18为吸附剂。对影响分散液液微萃取效率的因素(萃取溶剂种类及体积、分散剂体积等)进行优化,同时分析了实验过程中添加掩蔽试剂L-古洛糖酸γ-内酯(AP)对基质效应补偿作用的影响。在最佳实验条件下,19种有机磷在辣椒和大葱中3个添加水平(0.05,0.1,0.5 mg/kg)的回收率为76.9%~126.8%,相对标准偏差为0.6%~7.3%,检出限(S/N=3)为0.10~0.50μg/kg。该方法简单、高效、重现性好、富集倍数高,可用于蔬菜中有机磷农药的快速检测。     

超声辅助离子液体分散液液微萃取/高效液相色谱法测定新型抗艾药ACC007

该文提出了一种基于超声辅助离子液体分散液液微萃取/高效液相色谱(HPLC)测定血清及药片中ACC007含量的新方法.在超声辅助下,无需分散剂即可将疏水性离子液体1-辛基-3-甲基咪唑六氟磷酸盐([C8mimPF6])形成的细小液滴分散于样品溶液中,从而有效萃取ACC007,萃取率在94.0％以上.实验对萃取剂种类、萃取...     

分散液相微萃取/液相色谱串联质谱法快速测定猪尿中的盐酸克伦特罗与氯霉素

采用分散液相微萃取净化技术,建立了快速测定猪尿中盐酸克伦特罗和氯霉素残留的高效液相色谱-串联质谱分析方法.取5 mL猪尿样品,分别加入5 ngD9-盐酸克伦特罗和D5-氯霉素内标,调节pH至10.0,加入10％ NaC1,经250 μL三氯甲烷和750 μL异丙醇分散萃取后离心,转移下层沉淀,氮吹后以甲醇水溶液定容,采...     

Magnetic Stirring-Assisted Dispersive Suspended Microextraction with Solidification of a Floating Organic Droplet for the Determination of Trace Fungicides in Water and Wine

For the first time, a simple method for magnetic stirring-assisted dispersive suspended microextraction has been developed for the determination of three fungicides (azoxystrobin, diethofencarb, and pyrimethanil) in water and wine samples. The method is based on the solidification of a floating organic droplet coupled with high performance liquid chromatography. In the proposed method, the low toxicity solvent 1-dodecanol was used as the extractant. Both the extraction and phase separation process were performed with magnetic stirring. No centrifugation step was involved. After separating the two phases, the extraction solvent droplet was easily collected through solidification at lower temperature. Important parameters such as the kind and volume of organic extraction solvent, extraction and restoration speed, extraction and restoration time, and salt concentration were optimized. Under the optimal conditions, the limits of detection for the analytes varied from 0.14 to 0.26 µg L^?1. The enrichment factors ranged from 125–200. The linearity ranges were 1–2000 µg L^?1, yielding correlation coefficients (r) higher than 0.9990. The relative standard deviation (n = 6) at two spiked level of 0.2 µg mL^?1 and 4 µg L^?1 varied between 2.2% and 7.8%. Finally, the developed technique was successfully applied to determine target fungicides in real water and wine samples, where the obtained recoveries ranged from 83.8–105.3%     

Highly Efficient Micro-Scale Liquid-Liquid In-Flow Extraction of 99mTc from Molybdenum

The trend to achieve even more compact-sized systems is leading to the development of micro-scale reactors (lab-on-chip) in the field of radiochemical separation and radiopharmaceutical production. Technetium-99m extraction from both high and low specific activity molybdenum could be simply performed by MEK-driven solvent extraction if it were not for unpractical automation. The aim of this work is to develop a solvent extraction and separation process of technetium from molybdenum in a micro-scale in-flow chemistry regime with the aid of a capillary loop and a membrane-based separator, respectively. The developed system is able to extract and separate quantitatively and selectively (91.0 ± 1.8% decay corrected) the [^99mTc]TcO₄Na in about 20 min, by using a ZAIPUT separator device. In conclusion, we demonstrated for the first time in our knowledge the high efficiency of a MEK-based solvent extraction process of ^99mTc from a molybdenum-based liquid phased in an in-flow micro-scale regime.