微滴液相微萃取技术用于气相色谱-质谱法测定食品中的酞酸酯

将一种新型、简单、快速、环境友好的萃取方法微滴液相微萃取(SDME)与气相色谱-质谱法结合用于快速分析食品中的几种酞酸酯(PAEs)。考察了萃取溶剂的种类及用量、微液滴在样品溶液中的深度、萃取时间及搅拌子的搅拌速度对微滴液相微萃取的影响。优化的萃取条件为:萃取溶剂为2.0 μL甲苯,微液滴在样品溶液中的深度为0.75 cm,搅拌速度为1000 r/min,萃取时间为20 min。该方法的线性范围为0.1～4000 μg/L,检测限为25 ng/L～0.8 mg/L,加标回收率为87.1%～114.4%,相对标准偏差为4.9%～11.6%。微滴液相微萃取所需的有机溶剂量很小,是一种快速、简单、安全、有效的水溶性样品的前处理方法。     

液相微萃取/气相色谱-质谱法分析食品中的防腐剂和抗氧化剂

采用液相微萃取/气相色谱-质谱联用测定食品中的四种防腐剂和三种抗氧化剂。优化后的萃取条件为:2.0μL甲苯作萃取剂,微液滴在样品中深度为0.85cm,搅拌速度800r/min,萃取时间25min,溶液的pH=3,加入盐的质量浓度为10%。该方法线性范围为0.5～400mg/kg,检出限0.01～1.2mg/kg,加标回收率93.7%～113.4%,相对标准偏差2.7%～8.6%。     

单滴微萃取-气相色谱-质谱联用测定水中的硝基咪唑类药物

建立了单滴液相微萃取(SDME)与气相色谱-质谱(GC-MS)联用技术快速检测水中的硝基咪唑类药物,对影响萃取的因素(溶剂的种类及用量、萃取时间、萃取温度及搅拌子的搅拌速度)进行优化。优化的萃取条件为:溶剂为2.5μL正辛醇,温度为50℃,搅拌速度为600 r/min,时间为20 min。萃取后,微液滴转移至衍生化试管,于70℃水浴中衍生45 min,进样分析。该方法在水中的线性范围为0.5~400μg/L,线性相关系数良好(r0.998),检测限为0.16~0.57μg/L。加标自来水和湖水中的相对平均回收率为80.9%~103.6%,相对标准偏差为1.7%~9.0%。     

液相微萃取/离子色谱测定牛奶中的氨

以水为微滴萃取溶剂,采用顶空液相微萃取/离子色谱检测了牛奶中的氨.优化了顶空液相微萃取的实验条件:pH=12,萃取温度为35 ℃,萃取时间为15 min,搅拌速率为800 r/min,萃取溶剂体积为5 μL.测定氨的线性范围为10 ～300 μg·L-1(R2=0.998),检出限达1.8 μg·L-1,回收率为92% ～105%.     

离子液体顶空单滴微萃取分析中药中的高沸点挥发性成分

建立了分析中药中高沸点挥发性成分的离子液体顶空单滴微萃取-液相色谱法,并用于复方鲜竹沥液中愈创木酚的含量的测定.采用改进的悬滴装置,增大了液滴与微量进样器针尖处塑料套管的接触面积,使离子液体的液滴达12 μL,提高了液滴的稳定性及方法的灵敏度.考察并优化了影响萃取的因素,确定了萃取条件:以12 μL 1-丁基-3-甲基咪唑基六氟磷酸盐([PF6])为悬滴,在5 mL含36%(w/V)NaCl的样品溶液中,萃取温度80 ℃、搅拌速度1000 r/min的条件下,顶空萃取30 min,萃取后直接将液滴吸回微量进样器,进行HPLC检测.愈创木酚在0.05～1.6 mg/L范围内线性关系良好(r=0.9997); 检出限为0.39 μg/L,愈创木酚的加样回收率为97.6%,RSD为2.5%.本方法操作简单、定量准确,样品前处理简单,成本低,无污染.     

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。     

气泡微萃取-气相色谱-质谱法测定尿中咖啡因

建立了气泡微萃取结合气相色谱/质谱技术(GC-MS)测定尿中咖啡因的方法.对影响萃取效率的实验条件进行了优化,确定了最佳萃取条件:三氯甲烷作为萃取溶剂,萃取溶剂暴露体积1 μL,气泡体积1.6 μL,搅拌速度300 r/min,萃取时间5 min,盐度15%(m/V),气泡与磁子间距离1 cm.在优化条件下,所建立方法在咖啡因浓度0.005~10 mg/L范围内有较好的线性关系,相关系数可达0.986,检出限为0.003 mg/L.在人尿液中添加不同浓度的咖啡因(0.050、0.500和5.000 mg/L),回收率为89.2%~107.5%,相对标准偏差小于8%(n=6).     

液相微萃取-气相色谱法测定水样中微量酚类污染物

提出了一种静态液相微萃取与气相色谱联用技术测定水样中微量酚类污染物的方法.以苯酚为代表,考察了萃取溶剂种类和用量、搅拌速度、萃取时间、pH值及离子强度对酚类化合物的静态液相微萃取效率的影响.优化的萃取条件为:3.0μL甲苯为萃取剂(对硝基甲苯为内标),搅拌速度150 r·min-1,萃取时间20 min,pH为2.2,离子强度为200 g·L-1氯化钠溶液.在优化的萃取和色谱条件下,苯酚和氯酚的线性范围分别为0.02～20.00 mg·L-1和0.02～10.00 mg·L-1,检出限(3S/N)为0.01 mg·L-1.用此方法分析了一种湖水样品中的酚类污染物,并以此样品为基体进行回收及精密度试验,测得平均回收率为93.7%,相对标准偏差(n=7)为6.3%.     

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。     

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%.     

环境水样中百菌清残留的单滴微萃取-反相液相色谱测定

应用单滴微萃取(SDME)-反相液相色谱(RPLC)检测了环境水样中的百菌清残留.优化了单滴微萃取条件:环己烷萃取剂6 μL、单滴体积2 μL、搅拌速率350 r/min、萃取时间40 min、水溶液温度35 ℃、无盐度.水样经单滴微萃取后,使用Hypersil C18柱反相液相色谱分离测定百菌清.反相液相色谱条件:100%甲醇流动相、流速1.0 mL/min、柱温25 ℃、224 nm检测.方法的线性范围、检出限、相对标准偏差和富集倍数分别为1.0 ～50 μg/L、0.02 μg/L、6.1%和427倍.采用该法对环境水样中的百菌清残留进行了测定,环境水样的加标回收率为98% ～106%.     

Comparison of efficiencies between single-drop microextraction and continuous-flow microextraction for the determination of methomyl in natural waters

Two liquid-phase microextraction (LPME) approaches, static direct-immersed single-drop microextraction (DI-SDME) and continuous-flow microextraction (CFME), were used to extract methomyl in water samples and their respective extraction efficiencies were compared. Several important parameters affecting extraction efficiency such as the type of extraction solvent, solvent drop volume, stirring speed or flow rate, extraction time and salt concentration were optimised. The optimised conditions were as follows: 3.0-µL tetrachloroethane (C₂H₂Cl₄) as the extraction solvent, 15% NaCl (w/v), 15 min extraction time and stirring speed at 600 rpm for DI-SDME; 3.5-µL C₂H₂Cl₄ as the extraction solvent, 15% NaCl (w/v), 21 min extraction time and flowing rate at 0.8 mL min^?1 for CFME. Under the previous optimal conditions, the linear range, detection limit (S/N = 3) and precision (RSD, n = 6) were 5.0-5000 ng mL^?1, 1.5 ng mL^?1, 6.9% for DI-SDME, and 4.0–10000 ng mL^?1, 2.5 ng mL^?1, 4.6% for CFME, respectively. Lake and river water samples were successfully analysed by DI-SDME and CFME. The result demonstrated that both SDME and CFME techniques are simple, low cost and amity to environment. As a result, the two approaches have tremendous potential in trace analysis of methomyl in natural waters.     

Screening method for phthalate esters in water using liquid-phase microextraction based on the solidification of a floating organic microdrop combined with gas chromatography-mass spectrometry

A simple and efficient liquid-phase microextraction (LPME) technique was developed using directly suspended organic microdrop coupled with gas chromatography–mass spectrometry (GC–MS), for the extraction and the determination of phthalate esters (dimethyl phthalate, diethyl phthalate, diallyl phthalate, di-n-butyl phthalate (DnBP), benzyl butyl phthalate (BBP), dicyclohexyl phthalate and di-2-ethylhexyl phthalate (DEHP)) in water samples. Microextraction efficiency factors, such as nature and volume of the organic solvent, temperature, salt effect, stirring rate and the extraction time were investigated and optimized. Under the optimized extraction conditions (extraction solvent: 1-dodecanol; extraction temperature: 60 °C; microdrop volume: 7 μL; stirring rate: 750 rpm, without salt addition and extraction time: 25 min), figures of merit of the proposed method were evaluated. The values of the detection limit were in the range of 0.02–0.05 μg L⁻¹, while the R.S.D.% value for the analysis of 5.0 μg L⁻¹ of the analytes was below 7.7% (n = 4). A good linearity (r² ≥ 0.9940) and a broad linear range (0.05–100 μg L⁻¹) were obtained. The method exhibited enrichment factor values ranging from 307 to 412. Finally, the designed method was successfully applied for the preconcentration and determination of the studied phthalate esters in different real water samples and satisfactory results were attained.     

Determination of decabromodiphenyl ether in water samples by single-drop microextraction and RP-HPLC

This paper describes the development of a new method using single-drop microextraction (SDME) and RP-HPLC for the determination of decabromodiphenyl ether (BDE-209) in water samples. The effects of SDME parameters such as extraction solvent, microdrop volume, extraction time, stirring speed, salt concentration, and sample pH on the extraction performance are investigated. Under optimal extraction conditions (extraction solvent, toluene; solvent drop volume, 3.0 microL; extraction time, 15 min; stirring speed, 600 rpm; no addition of salt and change of sample pH), the calibration curve was drawn by plotting peak area against a series of BDE-209 concentrations (0.001-1 microg/mL) in aqueous solution; the correlation coefficient (r) was 0.9998. The limit of detection was 0.7 ng/mL. The enrichment factor was 10.6. The precision of this method was obtained by six successive analyses of a 100 ng/mL standard solution of BDE-209, and RSD was 4.8%. This method was successfully applied to the extraction of BDE-209 from tap and East Lake water samples with relative recoveries ranging from 92.5 to 102.8% and from 91.5 to 96.2%, respectively, and the relative standard deviations (n = 3) were 4.4 and 2.2%. The proposed method is acceptable for the analysis of BDE-209 in water samples.     

Determination of the chloroacetanilide herbicides in waters using single-drop microextraction and gas chromatography

In this article, a new method using single-drop microextraction (SDME) and gas chromatography micro-electron capture detection (GC-μECD) for the determination of chloroacetanilide herbicides (alachlor, acetochlor, metolachlor, pretilachlor and butachlor) residues was developed. The effects of SDME parameters such as extraction solvent, stirring rate, ionic strength, microdrop volume and extraction time were optimized. The optimum experimental conditions found were: 1.6 μl toluene microdrop, 5 ml water sample, 400 rpm stirring rate, 15 min extraction time and no salt addition. Analytical parameters such as linearity, repeatability and limit of detection were also evaluated. The proposed method was proved to be a simple and rapid analytical procedure for chloroacetanilide herbicides in water with limits of detection 0.0002–0.114 μg/l. The relative recoveries range from 80% to 102% for all the target analytes, with the relative standard deviations varying from 3.9% to 11.7%.     

Headspace single-drop microextraction with in-drop derivatization for aldehyde analysis

A new technique, headspace single-drop microextraction (HS-SDME) with in-drop derivatization, was developed. Its feasibility was demonstrated by analysis of the model compounds, aldehydes in water. A hanging microliter drop of solvent containing the derivatization agent of O-2,3,4,5,6-(pentaflurobenzyl)hydroxylamine hydrochloride (PFBHA) was shown to be an excellent extraction, concentration, and derivatization medium for headspace analysis of aldehydes by GC-MS. Using the microdrop solvent with PFBHA, acetaldehyde, propanal, butanal, hexanal, and heptanal in water were headspace extracted and simultaneously derivatized. The formed oximes in the microdrop were analyzed by GC-MS. HS-SDME and in-drop derivatization parameters (extraction solvent, extraction temperature, extraction time, stirring rate microdrop volume, and the headspace volume) and the method validations (linearity, precision, detection limit, and recovery) were studied. Compared to liquid-liquid extraction and solid-phase microextraction, HS-SDME with in-drop derivatization is a simple, rapid, convenient, and inexpensive sample technique.     

Headspace single-drop microextraction with in-drop derivatization and capillary electrophoretic determination for free cyanide analysis

A new method involving headspace single-drop microextraction (SDME) with in-drop derivatization and CE is developed for the preconcentration and determination of free cyanide. An aqueous microdrop (5 microL) containing Ni(II)-NH(3) (as derivatization agent), sodium carbonate and ammonium pyromellitate (as internal standard) was used as the acceptor phase. The extracted cyanide forms a stable Ni(CN)(4) (2-) complex which is then determined by CE. Common experimental parameters (sample and acceptor phase pH, extraction temperature, extraction time and sample ionic strength) affecting the extraction efficiency were investigated. Using headspace SDME, free cyanide can be effectively extracted from the neutral solutions, i.e. without the acidification of the sample which often is prone to errors due to incomplete liberation and artefactual cyanide production. Proposed SDME-CE method provided about 58-fold enrichment in 20 min. The calibration curve was linear for concentrations of CN(-) in the range from 0.25 to 20 micromol/L (R(2) = 0.997). The LOD (S/N = 3) was estimated to be 0.08 micromol/L of CN(-). Such a detection sensitivity is high enough for free cyanide determination in common environmental and physiological samples. Finally, headspace SDME was applied to determine free cyanide in human saliva and urine samples with spiked recoveries in the range of 91.7-105.6%. The main advantage of this method is that sample clean-up, preconcentration and derivatization procedures can be completed in a single step. In addition, the proposed technique does not require any sample pretreatment and thus is much less susceptible to interferences compared to existing methods.     

固相萃取-气相色谱-质谱法测定食品中23种邻苯二甲酸酯

建立了同时检测食品中23种邻苯二甲酸酯类化合物的固相萃取-气相色谱-质谱(GC-MS)分析方法。样品经正己烷或乙腈提取、玻璃ProElut PSA固相萃取柱净化,GC-MS选择离子监测模式(SIM)测定。考察了不同种类食品的提取、净化方法。23种邻苯二甲酸酯的线性范围除邻苯二甲酸二异壬酯(DINP)和邻苯二甲酸二异癸酯(DIDP)为0.5～5 mg/L外,其余均为0.05～5 mg/L,相关系数(r)除DIDP外均大于0.99。方法的检出限(信噪比为3)为0.005～0.05 mg/kg,定量限(信噪比为10)为0.02～0.2 mg/kg。在10种食品基质中3个加标水平的平均回收率为77%～112%,相对标准偏差(RSD,n=6)为4.1%～12.5%。该方法稳定、可靠,操作简单,适用于食品中邻苯二甲酸酯类化合物的检测与确证。