微波辅助萃取法测定烟草中有机氯类农药残留量

建立了一种微波辅助萃取-固相萃取净化测定烟草中17种有机氯类农药残留量的新方法. 样品用V(正己烷):V(乙酸乙酯)＝1:1提取, 提取液经Florisil固相萃取柱净化后, 采用气相色谱-电子捕获检测器(GC-μECD)进行检测. 17种有机氯农药的0.01、 0.05 mg/kg和0.5 mg/kg加标回收率均在82%以上, RSD在0.11%～8.2%之间, 能满足当前烟草中有机氯农药残留的检测要求.     

响应面法优化烟草中有机氯农药残留的加速溶剂萃取

采用响应面法(RSM)优化了烟草中有机氯农药残留的加速溶剂萃取(ASE)条件,并利用气相色谱-质谱法进行定性定量分析.以有机氯农药平均回收率为指标,考察了加速溶剂萃取过程中提取溶剂、萃取温度、冲洗溶剂体积、循环次数和吹扫时间等因素对烟草中有机氯提取效果的影响.经响应面优化的最佳ASE条件为:提取溶剂为正己烷-丙酮(体积比9:1),萃取温度107 ℃,冲洗体积92%,吹扫时间92 s,循环次数3次.在优化条件下,烟草有机氯农药萃取回收率理论预测值为96.5%,验证值为94.9%.结果表明,响应面法适用于烟草中有机氯农药残留加速溶剂萃取条件的优化,经优化得到的萃取参数准确可靠,具有实用价值.     

气相色谱-负化学电离源-飞行时间质谱测定烟草中有机氯农药残留

采用QuEChERS前处理方法,建立了气相色谱-负化学电离源-飞行时间质谱(GC-NCI-TOF-MS)检测烟草中10种有机氯农药残留的分析方法。样品采用乙酸乙酯-正己烷(1 : 1, v/v)溶液提取,提取液经N-丙基乙二胺(PSA)、无水硫酸镁分散固相萃取净化,用GC-NCI-TOF-MS检测分析。根据有机氯化合物特征离子的精确质量数、同位素离子峰簇、碎片离子丰度比和保留时间对目标物定性鉴定,外标法定量。10种有机氯农药的线性关系良好,相关系数 (r²)均大于0.997;相对标准偏差小于6.5%;检出限为0.04~0.80 μ g/kg;加标回收率为77.2%~93.0%。该方法简单快速、灵敏度高、准确性好,适用于烟草中有机氯农药残留的定性分析和定量检测。     

气相色谱法同时测定山药和葛根中27种有机氯及拟除虫菊酯农药残留量

建立了山药和葛根中20种有机氯和7种拟除虫菊酯农药残留的提取、净化及其残留量测定的方法。样品采用丙酮-正己烷(4:3,V/V)提取,经凝胶渗透色谱净化后,采用气相色谱-电子捕获检测器检测。结果表明山药和葛根样品基质4水平添加条件下,27种农药的回收率(n=7)为80.1%～103.7%,相对标准偏差为1.9%～11%,最低检测限为0.09～1.82μg/kg,符合农药多残留检测要求。方法可用于山药和葛根中多种有机氯及拟除虫菊酯农药残留量的检测。     

气相色谱法测定烟草中有机磷农药残留量

提出了用气相色谱-脉冲火焰光度检测器(GC-PFPD)测定烟草中5种有机磷农药残留量的方法,采用乙腈超声提取烟草中残留的有机磷农药,提取液经蒸干等操作后,用凝胶渗透色谱法净化。用乙酸乙酯及环己烷(1+1)混合溶液作流动相淋洗凝胶柱,分取部分淋出液用HP-5弹性石英毛细管柱进行分离,GC-PFPD检测,外标法定量。所测5种农药的标准加入回收率在81.4%～99.8%之间,测得结果的相对标准偏差(n=6)在3.27%～8.42%之间。方法的检出限(3S/N)在0.02～0.04 mg.L-1之间。     

超声提取-气相色谱法测定鱼腥草中有机氯农药残留

提出了超声提取-气相色谱法测定鱼腥草中有机氯农药残留方法。采用丙酮-石油醚(1+1)混合溶剂超声提取30 min,然后浓硫酸净化、旋转蒸发浓缩,最后用气相色谱-电子捕获检测器(ECD)进行检测。有机氯农药的线性范围在0.001~0.20 mg·L-1之间,方法的检出限(3S/N)为0.023~0.29μg·kg-1,加标回收率在73.0%~115%之间,相对标准偏差(n=5)在1.4%~14%之间。本法与药典法对比,其回收率较高,适用于鱼腥草中有机氯农药的检测。     

气相色谱-质谱法测定茶叶中的25种有机氯农药残留

利用气相色谱-质谱(GC-MS)联用技术建立了茶叶中25种有机氯农药残留同时测定的方法。茶叶样品中有机氯农药残留通过正己烷-丙酮(体积比为2∶1)溶液提取,浓缩后过弗罗里硅土柱净化,采用正己烷-乙酸乙酯(体积比为9∶1)溶液淋洗,GC-MS选择离子监测模式(SIM)检测。方法的线性范围为0.010～0.500 mg/L。在茶叶样品中0.01～0.20 mg/kg加标水平下有机氯混标的加标回收率为70.8%～105.5%,相对标准偏差为1.6%～12.7%。除硫丹Ⅰ和硫丹Ⅱ的定量限为0.02 mg/kg以外,其余23种有机氯农药的定量限均为0.01 mg/kg。     

气相色谱-串联质谱多离子监测分析土壤中的有机氯农药残留

采用气相色谱-串联质谱(GC-EI-MS/MS)联用技术,结合索氏萃取提取及佛罗里硅土净化分析土壤中有机氯农药残留.通过对检测模式、母离子选择、碰撞能量、多反应监测的选择等条件优化,可实现20种有机氯农药的基线分离.在优化的条件下,有机氯农药的定量限为5.6×10-4～9.6 ng/mL;样品加标回收率为51.6%～130%.     

生晒参、全须生晒参中19种有机氯残留农药的毛细管气相色谱测定

建立了生晒参、全须生晒参中19种有机氯农药残留的毛细管气相色谱分析方法。对样品中六六六的4种异构体、滴滴涕的5种异构体、四氯苯胺、六氯苯、五氯硝基苯、七氯、五氯苯胺、艾氏剂、百菌清、环氧七氯、狄氏剂及异狄氏剂共19种有机氯农药的残留量进行了测定。以石油醚-丙酮混合物作为提取剂,样品采用索氏提取,提取液用弗罗里硅土柱层析净化。采用OV-1701石英毛细管气相色谱柱分离样品,ECD检测器进行检测。在3个水平添加时的回收率(n=5)分别为75.7%~96.1%、78.8%~111.6%和81.7%~115·2%;相对标准偏差分别为2.4%~10.6%、2.1%~9.8%和1.4~10.0%。方法用于生晒参和全须生晒参样品中农药残留的测定,结果满意。     

固相萃取-气相色谱法同时测定花生中18种有机氯农药残留

利用气相色谱(GC)建立了花生中18种有机氯农药同时测定的方法。花生中有机氯农药残留通过乙腈提取,减压浓缩后过弗罗里固相萃取柱净化,采用正己烷-丙酮(体积比为9∶1)溶液淋洗,淋洗液氮吹近干后以正己烷定容,应用微池电子捕获检测器(μECD)检测。氟氯氰菊酯和溴氰菊酯的检出限分别为50和100g/kg,其余16种有机氯农药检出限均为10μg/kg。在花生样品中添加检测限水平有机氯混标溶液,加标回收率为71.28%～116.58%,测定结果的相对标准偏差为4.08%～18.16%(n=4或5)。     

快速溶剂萃取-气相色谱法同时测定含脂羊毛中的28种有机氯拟除虫菊酯杀虫剂的残留量

建立了快速溶剂萃取-气相色谱法同时测定含脂羊毛中28种有机氯、拟除虫菊酯杀虫剂残留量的方法。在80 ℃、10.34 MPa条件下用正己烷饱和的乙腈快速提取样品,提取物经冷冻除脂、浓缩、固相萃取净化处理后直接用气相色谱分析。结果表明:16种有机氯杀虫剂在0.005～1.0 mg/L范围内,9种拟除虫菊酯杀虫剂及三氯杀螨醇、三氯杀螨砜在0.01～2.0 mg/L范围内,氟氯苯菊酯在0.02～4.0 mg/L范围内,其峰面积与质量浓度呈良好的线性关系。28种有机氯、拟除虫菊酯杀虫剂的平均回收率为67.2%～107.7%,相对标准偏差为2.6%～29.0%。结果表明：该方法具有操作简便、快速方便、灵敏度高等特点,完全可满足含脂羊毛中28种有机氯拟除虫菊酯杀虫剂残留量初筛检测的要求。     

多壁碳纳米管固相萃取净化气相色谱法分析蔬菜中有机氯和拟除虫菊酯农药残留

建立了多壁碳纳米管为吸附剂的固相萃取(SPE)净化、气相色谱-电子捕获检测(GC-ECD)测定蔬菜中6种有机氯和7种拟除虫菊酯农药的方法。采用双柱(HP-50和HP-1色谱柱)双检测器进行定性和定量分析。蔬菜样品采用乙腈提取,多壁碳纳米管SPE柱净化,正己烷溶解上样,丙酮-正己烷(7:3, v/v)洗脱,13种农药中有11种农药的添加回收率高于70%。将该净化方法用于荷兰黄瓜、卷心菜、红圣女果、奶油生菜、紫甘蓝、韭菜、大葱和洋葱等样品的净化,与弗罗里硅土SPE柱相比较,净化效果更好,表明多壁碳纳米管具有较强的吸附去除色素的能力,可以避免色素对测定的干扰。     

固相萃取-气相色谱法测定茶叶中残留的92种农药

建立了茶叶中92种农药多残留的气相色谱分析方法。茶叶样品用乙腈一次性提取后,有机磷类农药经Envi-Carb固相小柱净化,用10 mL乙腈-甲苯(体积比为3∶1)洗脱剂淋洗,气相色谱-火焰光度检测器(GC-FPD)检测;有机氯类和拟除虫菊酯类农药经串联Envi-Carb和NH2固相小柱净化,用5 mL乙腈-甲苯(体积比为3∶1)洗脱剂淋洗,GC-电子捕获检测器(ECD)检测。采用外标法定量。添加回收试验的结果表明:92种农药的平均回收率为80.3%～117.1%,相对标准偏差为1.5%～9.8%。方法的检出限为0.0025～0.10 mg/kg。该方法的灵敏度、准确度和精密度均符合农药残留测定的技术要求。     

Development of a solid-phase microextraction method for direct determination of pentachlorophenol in paper and board samples: Comparison with conventional extraction method

A solid-phase microextraction (SPME) method has been developed for the determination of pentachlorophenol (PCP) in paper and board samples. The analytical procedure involves direct extraction of PCP from paper and board samples and determination by gas chromatography with electron capture detection (GC-ECD). Two kinds of commercially available fibres; 100 microm polydimethylsiloxane (PDMS), apolar, and 85 microm polyacrylate (PA), quite polar, were evaluated to determine the extraction efficiency of pentachlorophenol. Parameters affecting the extraction process, such as temperature and time, were studied. Moreover, time of desorption and the effect of addition of salt were also investigated. The optimized procedure was applied to the analysis of pentachlorophenol (PCP) in five samples of virgin and recycled paper and board. The PCP content was determined by GC-ECD. To evaluate the effectiveness of the proposed method, it was compared with conventional extraction method with liquid-liquid extraction and derivatization. Detection limit of 0.015 microg/g for PCP in paper was achieved with a RSD of 14%.     

Determination of 21 organochlorine pesticides in tree leaves using solid-phase extraction clean-up cartridges

A method to determine 21 organochlorine pesticides (OCPs) in tree leaves [chestnut (Castanea sativa), hazel (Corylus avellana), oak (Quercus robur) and walnut tree (Juglans regia)] based on microwave-assisted extraction (MAE) followed by solid-phase extraction (SPE) clean-up is described. After extraction with hexane:acetone (50:50), four different sorbents (Florisil, tandem Florisil + alumina, silica and ENVI-Carb) were assayed for the clean-up step. Pesticides were eluted with 5 mL of hexane:ethyl acetate (80:20) and determined by gas chromatography and electron capture detection (GC-ECD). Carbon was the sorbent, which provided colourless eluates and chromatograms with less interferent compounds. Analytical recoveries obtained were ca. 100% for all the studied pesticides with this sorbent.     

Electrodeposited polyaniline as a fiber coating for solid-phase microextraction of organochlorine pesticides from water

The study on the performance of polyaniline as a fiber coating for solid-phase microextraction (SPME) purposes has been reported. Polyaniline coatings were directly electrodeposited on the surface of a stainless steel wire and applied for the extraction of some organochlorine pesticides (OCPs) from water samples. Analyses were performed using GC-electron capture detection (GC-ECD). The results obtained show that polyaniline fiber coating is suitable for the successful extraction of organochlorine compounds. This behavior is most probably due to the porous surface structure of polyaniline film, which provides large surface areas and allowed for high extraction efficiency. Experimental parameters such as adsorption and desorption conditions were studied and optimized. The optimized method has an acceptable linearity, with a concentration range of 1-5000 ng/L. Single fiber repeatability and fiber-to-fiber reproducibility were less than 12 and 17%, respectively. High environmental resistance and lower cost are among the advantages of polyaniline fibers over commercially available SPME fibers. The developed method was applied to the analysis of real water samples from Yangtse River and Tianmu Lake.     

Nano-structured polyaniline-ionic liquid composite film coated steel wire for headspace solid-phase microextraction of organochlorine pesticides in water

A novel nano-structured polyaniline-ionic liquid (i.e. 1-butyl-3-methylimidazolium hexafluorophosphate, BMIPF(6)) composite (BPAN) film coated steel wire was prepared by electrochemical deposition. Scanning electron microscopy images showed that the obtained porous BPAN coating consisted of nanofibers, whose diameter ranged from 50 to 80 nm. Furthermore, the novel nano-structured composite coating was very stable at relatively high temperatures (up to 350 °C) and it could be used for more 250 times without obvious decrease of the extraction efficiency. The novel BPAN coating was used for the headspace solid-phase microextraction (HS-SPME) of organochlorine pesticides (i.e. hexachlorocyolohexane, dichlorodiphenyldichloroethylene, dichlorodiphenyldichloroethane, dichlorodiphenyltrichloroethane), coupled with gas chromatography-electron capture detection (GC-ECD). The BPAN coating showed better analytical capability on the whole compared with common polyaniline (PANI) and polydimethylsiloxane (PDMS) coatings. The key parameters influencing extraction efficiency were investigated and optimized, including desorption time, stirring speed, extraction temperature, extraction time and ionic strength. The relative standard deviations (RSDs) for single fiber repeatability ranged from 2.3 to 8.7% (n=6) and the RSDs for fiber-to-fiber reproducibility (n=6) were 4.2-12.1%, respectively. The linear ranges exceeded three magnitudes with correlation coefficients above 0.99. The detection limits were 0.12-0.31 ng L(-1). The proposed method was successfully applied for the determination of organochlorine pesticides in lake water, waste water and sewage treatment plant effluent with good recoveries from 88.9 to 112.9%.     

固相萃取-毛细管气相色谱法测定枇杷花中有机氯农药残留量

建立了枇杷花中有机氯类农药残留量的固相萃取-毛细管气相色谱(SPE-CGC)分析方法。对采自福建蒲田等12地的枇杷花中六六六(4种异构体)、滴滴涕(4种异构体)、五氯硝基苯共9种有机氯农药的残留量进行了测定。样品采用丙酮超声波提取,浓缩后过Florisil固相萃取小柱净化,洗脱剂为V(正己烷)∶V(丙酮)100∶1。用DB-1701弹性石英毛细管气相色谱柱分离样品,微电子捕获检测器进行检测。9种有机氯农药的峰面积与其质量浓度均有良好的线性关系,相关系数均大于0.999,最低检测限为0.016~0.125μg/L,样品的加标回收率为85.4%~106.9%,相对标准偏差为1.8%~9.8%。该方法能够满足农药残留检测的要求。     

Rapid and sensitive determination of two degradation products of flumethrin in honey by ultrasonically assisted extraction and gas chromatography with electron capture detection

A rapid and sensitive method for the determination of 4-fluoro-3-phenoxybenzaldehyde cyanohydrin (FPBC) and 4-fluoro-3-phenoxy-benzaldehyde (FPB) in honey samples using ultrasonically assisted extraction and gas chromatography with electron capture detection (GC-ECD) has been developed. The different factors affecting the efficiency of the extraction were carefully optimized. The honey sample was extracted with a mixture of hexane and dichloromethane (v/v, 1:1) utilizing the ultrasonically assisted technique and cleaned up by solid-phase extraction on Oasis HLB cartridges. The eluate was evaporated to dryness and residues were reconstituted to 1.0 mL with hexane and determined by GC-ECD. The calibration curves of fortified samples showed acceptable linear response (R(2) >0.99) over a range of 3-100 ng/g for FPBC and FPB in seven replicate determinations of six concentrations, respectively, and analysis of variance (ANOVA) with a lack-of-fit test was performed to validate the regression data. Overall average recoveries ranged from 90.9 to 106.2% for honey samples. The detection limits were 0.9 ng/g for FPBC and 1.0 ng/g for FPB, respectively. This method can be successfully applied to routine determination of two degradation products of flumethrin in honey samples.     

Determination of pyrethroid,organophosphate and organochlorine pesticides in water by headspace solid-phase microextraction

Simultaneous determination of pyrethroid, organophosphate (OP) and organochlorine (OC) pesticides in water was achieved with headspace solid-phase microextraction (HS-SPME) followed by gas chromatography-electron-capture detection (GC-ECD). The parameters affecting HS-SPME of pesticides from water were optimized, including extraction temperature, sample and headspace volumes, and sodium chloride amounts. The effects of desorption temperature, desorption time, and position of the fibre in the GC inlet were also investigated. Extraction temperature was the most important factor affecting the recoveries of analytes, and the optimized temperature was 96°C. The addition of salt did not increase extraction efficiencies of the pesticides from the water. The optimized desorption conditions in the GC were as follows: desorption time of 10?min; desorption temperature of 260°C; and a 2?cm position of the fibre in the inlet. The method detection limits were in the low-ng/L level with a linearity range of 50–1000?ng/L for the OCs, 50–5000?ng/L for the OP, and 50–20?000?ng/L for the pyrethroids. These data demonstrated that HS-SPME is a sensitive method for the determination of pyrethroid, OC, and OP pesticides in water.