茶叶中25种有机氯农药多残留气相色谱测定方法

利用气相色谱(GC)建立了茶叶中25种有机氯农药同时测定的方法。茶叶中有机氯农药残留通过正己烷-丙酮(体积比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9∶1)溶液淋洗,淋洗液吹氮至干后以正己烷定容供GC测定。标准工作曲线范围在0.005~0.500mg/L之间。在茶叶样品中0.005~0.100mg/kg水平有机氯混标加标回收率在71%~110%之间,相对标准偏差在4.6%~13.7%之间。除乙酯杀螨醇定量下限为8.0μg/kg以外,其余24种有机氯农药定量下限均为5.0μg/kg。     

凝胶渗透色谱-气相色谱同时测定糙米中拟除虫菊酯、有机氯农药和多氯联苯的残留量

基于凝胶渗透色谱（GPC）对脂类和色素的优良分离能力,系统研究了其对有机氯农药、拟除虫菊酯农药、多氯联苯和糙米基体的分离行为。介绍了一种可同时测定糙米中35种拟除虫菊酯、有机氯农药和多氯联苯的方法。样品用乙酸乙酯提取,凝胶渗透色谱净化,气相色谱-电子捕获检测法(GC-ECD)检测,外标法定量。在低、中、高浓度3个添加水平上的回收率分别为70.1%~107.4%,70.3%~109.9%和70.8%~109.5%,相对标准偏差（RSD）为2.3%~13.3%;有机氯农药和多氯联苯的检出限为0.07 μg/k     

凝胶渗透色谱技术在农药残留分析中的应用

综述了凝胶渗透色谱技术在食品农药残留分析中的应用、研究现状和存在的问题。测定的农药残留包含有机氯、有机磷、除虫菊酯和农药多残留等等。参考文献37篇。     

QuEChERS-凝胶渗透色谱/气相色谱-质谱法同时测定降尘中18种有机氯农药

建立了在线凝胶渗透色谱/气相色谱-质谱(GPC/GC-MS)测定大气降尘中18种有机氯农药残留的分析方法。样品经过简化QuEChERS方法处理后,经乙腈萃取,石墨化炭黑(GCB)净化,一步离心后过膜上机检测。采用该方法能在30 min内处理8~10个样品,配合GPC净化,不仅缩短了分析时间,而且提高了工作效率和结果的准确性。检测结果表明,18种有机氯农药在0.025~2.0 mg/L质量浓度范围内线性关系良好,相关系数为0.991 9~0.999 6,样品检出限为3.2~14.6μg/kg,定量下限为10.7~48.7μg/kg。在0.2、1.0 mg/kg 2个加标水平下,18种有机氯农药的平均回收率为78.6%~117.3%,相对标准偏差(RSD,n=5)为1.3%~5.1%。     

微波萃取-全自动凝胶色谱净化-气相色谱法同时测定太湖沉积物中多氯联苯和有机氯

建立了沉积物中多氯联苯和有机氯农药等39种持久性有机污染物的同时测定方法。样品用正己烷和丙酮(体积比为1∶1)进行微波提取,提取溶液经凝胶色谱和弗罗里硅土净化,浓缩后采用气相色谱法测定。回收率在68.8%~84.2%,检出限为0.05~0.25ng/g。方法适用于沉积物样品中多种多氯联苯和有机氯农药含量的同时测定。     

手性气相色谱同时测定土壤中5种有机氯农药对映体分数

1 引言 许多有机氯农药(OCPs)含有手性结构, 如α-六六六(α-HCH)、顺氯丹(CC)、反氯丹(TC)、o,p'-滴滴涕(o,p'-DDT)及其降解产物o,p'-滴滴滴(o,p'-DDD)等都是手性化合物.有机氯农药均以外消旋体的形式进入土壤环境后通常会发生对映体选择性降解,形成非外消旋体残留.当残留的有机氯农药从土壤中挥发出来时,这种手性特征会被保留,并且可以作为追溯有机氯农药迁移源的标识.本研究建立了手性气相色谱法同时测定α-HCH、CC、TC、o,p'-DDT 和o,p'-DDD 5种手性OCPs对映体分数的分析方法,并且将该方法运用于浙江某农田土壤中有机氯农药残留手性特征的测定.     

气相色谱-串联质谱法测定土壤中的有机氯农药

建立了气相色谱-串联质谱测定土壤中有机氯农药的方法,同时测定了上海郊区的20个农业土壤。样品前处理包括加速溶剂萃取(弗罗里硅土池内净化)和凝胶渗透色谱净化在线浓缩。采用多反应监测模式的气相色谱-串联质谱分析有机氯农药,降低了背景干扰,提高了分析的灵敏度。在0.001～2 mg/L的质量浓度范围内,各种农药标准溶液的线性相关系数均大于0.995。分别向3种实际土壤样品中添加农药的混合标准溶液,所测定的有机氯农药的平均回收率为65.9%～140.0%,相对标准偏差为1.5%～20.3%(n=5)。有机氯农药的检出限（S/N=3）为0.1～3.0 μg/kg,定量限（S/N=10）为0.3～8.0 μg/kg。实际土壤样品的测定结果表明：六六六(1.82～3.70 μg/kg)和六氯苯(0.94～9.8 μg/kg)有少量检出,滴滴涕的检出率高达100%,其含量范围较宽(1.08～308.76 μg/kg),平均值为53.28 μg/kg,其中85%的样品中滴滴涕含量/(滴滴伊+滴滴滴)含量的比值小于1,表明滴滴涕主要来自于早期的使用     

固态萃取搅拌棒技术与气相色谱联用测定植物中的有机氯农药

以固态萃取搅拌棒为样品前处理技术,采用气相色谱法分析了荞麦和苦参中的8种有机氯农药残留。实验对比了聚醚砜酮(PPESK)和聚二甲基硅氧烷(PDMS)对所测定的有机氯农药的相对萃取量(以峰面积计),发现前者是后者的1～11倍。用PPESK作萃取相,对萃取温度、萃取时间和盐浓度等萃取条件进行了优化,并考察了基质效应对萃取效率的影响。所用方法对荞麦中有机氯农药的LOD为4～85pg/g,重复性的RSD小于26%,回收率为83%～135%;对苦参中有机氯农药的LOD为3～17pg/g,重复性的RSD小于17%,回收率为82%～128%。     

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。     

加速溶剂萃取-凝胶色谱净化-气质联用测定土壤中15种有机氯农药残留的方法研究

建立了加速溶剂萃取-凝胶色谱净化-气质联用同时测定土壤中15种有机氯农药的分析方法。优化了凝胶色谱(GPC)净化的条件,比较了凝胶色谱净化及浓硫酸净化法对15种有机氯回收率的影响。结果表明,采用GPC净化能够有效避免浓硫酸净化对氯丹、异狄氏剂、硫丹、甲氧滴滴涕等农药回收率的影响,GPC净化的最佳收集时间为10~15 min,15种有机氯农药的回收率为56%~122%。15种有机氯农药在0.03~6.0 mg/L范围内具有较好的线性,相关系数达0.999以上,方法的检出限为0.1~5.0μg/kg,定量下限为0.4~16.0μg/kg。采用该方法对实际样品进行加标回收率实验,土壤样品的加标回收率为68%~122%,相对标准偏差为1.2%~5.9%。该方法简单、快捷、灵敏度高,已用于实际土壤样品的检测。     

液液微萃取-甲基衍生化/气相色谱法对水中氯代酸除草剂的测定

在pH大于12的条件下使水样中的氯代除草剂全部水解为盐,用正己烷和甲基叔丁基醚混合溶剂提取有机杂质,再在酸性条件下经5 mL甲基叔丁基醚提取,重氮甲烷甲基衍生化30 min后用带微电子捕获检测器的毛细管气相色谱分析,以4,4-二溴八氟联苯为内标物进行定量.茅草枯、麦草威、2,4-D、五氯苯酚的质量浓度分别在5.0 ～500、1.0 ～200、5.0 ～500、0.5 ～100 μg/L范围内与色谱峰面积呈良好的线性关系(r= 0.994 5 ～0.998 0),检出限分别为1.0、0.5、1.0、0.1 μg/L.用该法测定南京玄武湖水样中的茅草枯,其质量浓度为7.1 μg/L,4种被测组分在高、中和低添加水平下的回收率分别为102% ～105%、96% ～110%、87% ～109%.同时建立了一种生产重氮甲烷的新原料--N-亚硝基-N-甲基脲的简易方法.     

用毛细管色谱柱分离有机磷农药

本文介绍了用SE-30毛细管柱、高速率程序升温分离13种有机磷农药。其分离效果较好,分析速度较快,有良好的线性关系和重复性。     

Analysis of Seven Herbicides by Gas-Liquid Chromatography

Simutaneous analysis of seven commonly used herbicides, 2,4-D methyl ester, 2,4-D methyl ester, 2,4,5-T methyl ester, silvex methyl ester, ramrod, CIPC and DEF, by gas-liquid chromatography with an electron capture detector was attempted. Two packed columns (which are generally used for the analysis of chlorinated pesticides) and two chemically bonded fused silica capillary columns were used for the analysis. When the packed columns were used, ramrod always interfered with the analysis of 2,4-D methyl ester and/or silvex methyl ester. Complete separation with reasonable analysis time can be achieved using one of the chemically bonded fused silica capillary columns.     

Analysis of toxaphene (PCC) and chlordane in biological samples by NCI mass spectrometry

Several recent reports indicate that both toxaphene (polychlorocamphene, PCC) and chlordane are widespread pollutants in our environment. These insecticides, both complex mixtures of chlorinated hydrocarbons, are difficult to separate from each other. Thus the analyses of them in environmental samples are difficult and furthermore complicated by interferences from other chlorinated hydrocarbons such as PCB and DDT compounds. Mass fragmentography using the negative ions formed by chemical ionization proved to be useful to selectively detect the toxaphenes and the chlordanes without interferences from DDT. High concentrations of PCB still influence on the results and have to be removed in the clean-up procedure.     

Analysis of Toxaphene (PCC) and Chlordane in Biological Samples by NCI Mass Spectrometry

Abstract

Several recent reports indicate that both toxaphene (polychlorocamphene, PCC) and chlordane are widespread pollutants in our environment. These insecticides, both complex mixtures of chlorinated hydrocarbons, are difficult to separate from each other. Thus the analyses of them in environmental samples are difficult and furthermore complicated by interferences from other chlorinated hydrocarbons such as PCB and DDT compounds. Mass fragmentography using the negative ions formed by chemical ionization proved to be useful to selectively detect the toxaphenes and the chlordanes without interferences from DDT. High concentrations of PCB still influence on the results and have to be removed in the clean-up procedure.     

薄层色谱在高速逆流色谱溶剂系统选择过程中的应用

本文对薄层色谱在高降流色谱的溶剂系统选择过程中的应用进行了研究，发现根据薄层色谱的斑点色度可以观察样品中各组分的含量差别及其在两相溶剂中分配系数间的差异，由此来判断溶剂系统的适用性，并确定哪一层适宜作流动相。     

Determination of Chlorinated Hydrocarbons Using Sep-Pak Cartridges and Gas Chromatography

Methods are described for the determination of chlorinated hydrocarbons at levels of parts per billion in water and nonaqueous environmental samples by gas chromatography with electron-capture detection. C₁₈, Florisil, alumina N and silica Sep-Pak cartridges were compared to evaluate their cleanup ability. The accuracy of the results of this analytical technique was proved by the analysis of a certified reference material (lake sediment EC-2).     

手性离子对色谱法

阐述了手性离子对色谱分离药物对映体的基本原理。在ＨＰＬＣ流动相中加入光学纯反离子可与流动相中的对映体生成非对映体复合物（离子对）,离子对复合物之间具有不同的稳定性和分配性质,并可与固定相发生不同的静电、疏水和氢键作用,进而差速迁移得以分离。影响方法立体选择性的主要因素有：反离子的性质（酸碱性、亲脂性、光学纯度）、反离子的浓度、流动相的组分、流动相的流速、固定相的性质和色谱柱的温度等。     

Studies on Chromatography Fingerprint of Hongqi by High-performance Liquid Chromatography

Chromatography fingerprint (CFP) of 10 samples of hongqi were studied. 23 commonpeaks were analyzed, their average similarity was 97.29%. CFP were positioned with main indexcomposition such as formononetin, calycosin and then the contents of index composition weredetermined. The character and exclusive of CFP of 10 samples of hongqi were clear. CFP andcontent determination of index composition of hongqi could be used to evaluate the quality of hongqicomprehensively.     

Fractionation and Characterization of Ozonated and Post Chlorinated Aquatic Fulvic Acid Using Gel Chromatography

Abstract

Extracted aquatic fulvic acid samples (HO10FA) from a brown lake Hohloh in the Black Forest (Germany) were ozonated at two different ozone doses and then chlorinated. In connection with liquid chromatography and further detection systems (UV and DOC) on gel matrix, a combined system (gel chromatograpy) was used for a detailed characterization of ozonated and post-chlorinated fulvic acid samples. The gel chromatographic characterization showed a slight decrease in DOC (14%) and SAC₂₅₄ (36%) at the end of 20 min ozonation whereas the low ozonation time (5 min) caused increases in DOC (6%) and SAC₂₅₄ (56%).