气相色谱-微池电子捕获检测法同时检测饮用水中多种有机污染物

本文建立了气相色谱-微池电子捕获检测法(GC-μECD),同时测定生活饮用水中百菌清、七氯、滴滴涕、六六六、林丹、六氯丁二烯、溴氰菊酯、1,1-二-氯苯、1,2-二氯苯、三氯苯、六氯苯11种有机氯,马拉硫磷、对硫磷、甲基对硫磷、毒死蜱、乐果、敌敌畏6种有机磷,以及硝基苯、2,4,6-三硝基甲苯、1,3-二硝基苯、邻,间,对硝基氯苯、2,4-二硝基氯苯,2,4-二硝基甲苯6种硝基苯类有机物的分析方法.样品经萃取后,采用OV-1701色谱柱(30 m×0.25 mm×0.25μtm)程序升温进行分离,用微池电子捕获检测器(μECD)进行检测,通过保留时间定性,外标法定量.结果表明该方法分离效果好,灵敏度高,选择性强,简便、快速、准确,能够满足同时测定生活饮用水中上述23种有机化合物的需要.     

气相色谱-电子捕获检测器同时测定硝基咪唑类药物

建立了气相色谱-电子捕获检测器同时测定硝基咪唑类药物含量的方法.样品用磷酸盐调节pH约为8.8,乙酸乙酯提取,无水硫酸钠脱水.采用CBP-1毛细管柱分离,电子捕获检测器检测.甲硝唑、替硝唑、奥硝唑分别在0.2～15 μg/mL、5.3～53μg/mL、4.0～40μg/mL范围内与峰面积呈良好线性关系,相关系数r分别为0.9993、0.9996、0.9995.样品加标回收率在95.8%～101%之间,相对标准偏差在1.8%～3.4%之间.本法简便、快速,可用于片剂和注射液中硝基咪唑类药物含量的测定.     

气相色谱-微池电子捕获检测器分析茶叶中杀螟丹的残留

介绍了一种快速、灵敏、可靠的适用于茶叶样品中杀螟丹残留量的气相色谱分析方法。茶叶样品经过0.05 mol/L盐酸溶液提取,液-液分配净化,在碱性条件下用正己烷萃取提取液中的杀螟丹,用毛细管气相色谱法-微池电子捕获检测器（μ-ECD）测定杀螟丹的残留量。结果表明：样品的添加回收率为70.2%~92.0%,相对标准偏差小于10%,方法的检测低限为0.01 mg/kg,符合农药残留分析的要求。     

固相微萃取-气相色谱-电子捕获快速富集检测海水中的有机氯农药

建立了固相微萃取(SPME)技术结合气相色谱-电子捕获(GC—ECD)检测方法,对大连近海养殖区内海水中的痕量12种有机氯农药进行检测,以便对该水域中海产品的食品安全性进行评估。该法具有较好的线性(相关系数为0．98～0．99),检出限达0．2～7ng／L,定量下限为0．66～23ng／L,重复测定的相对标准偏差小于10％(n=3),回收率为68％～133％。对影响SPME的参数和海水中存在的基质干扰进行探讨。     

全二维气相色谱-电子捕获检测器法分析土壤中毒杀芬同类物的残留

建立了全二维气相色谱-电子捕获检测器(GC× GC-μECD)检测土壤中毒杀芬同类物的分析方法.以非极性的DB- XLB(20 m×0.25 mm×0.25 μm)为第一色谱柱,中等极性的BPX-50(2 m×0.1 mm×0.1 μm)为第二色谱柱,对土壤中23种高关注毒杀芬同类物进行了分离鉴定,并采用基质曲线外标法进行定量分析.本方法在1～200,μg/L浓度范围内,毒杀芬同类物的线性相关系数(r2)均大于0.99,方法检出限(S/N=3)为0.039～0.482 μg/L,基质加标毒杀芬同类物的回收率为55％～115％,相对标准偏差(RSD)均小于30％(n=5).利用本方法对毒杀芬污染的土壤样品进行了测定,获得了较好的分离效果.     

气相色谱-电子捕获法测定血浆中的雷公藤甲素

 血浆样品经碱化后用乙醚 氯仿 (体积比为 3∶1)混合液提取 ,浓缩的提取物与三氟醋酐进行衍生化反应 ,用气相色谱法分离、63Ni电子捕获检测器测定雷公藤甲素的含量。色谱柱为SE 5 430m× 0 2 5mmi d 交联石英毛细管柱。雷公藤甲素的质量浓度在 1 0 μg/L～ 5 0 0 μg/L范围内与峰面积线性关系良好 (r =0 9990 ) ,在血浆中的平均回收率为 96 3% ,最小检测限为 0 5 μg/L。方法重现性好 ,准确、灵敏 ,无杂质干扰 ,数据准确可靠 ,可用于临床生物样品中雷公藤甲素含量的测定。     

微量糖缀合物中单糖组成的毛细管气相色谱分离和电子捕获检测

本文介绍了微量糖缀合物中单糖组成的电子捕获毛细管气相色谱分析,讨论了样品组分的分析条件。方法用于测定人脑神经节苷脂、人γ-球蛋白、微生物糖蛋白和植物多糖样品中的糖组分,样品量仅需0.1～5μg。     

乙酰衍生化气相色谱-电子捕获检测法分析尿中α-羟基三唑仑和α-羟基阿普唑仑

三唑仑和阿普唑仑是目前国内麻醉抢劫案件中最常使用的两种麻醉药物。为确定案件性质及取得证据等原因,案件发生后常需要进行受害人血、尿等体液中药物或其代谢物的分析。这两种药物作用强、剂量小,服药后血中药物及其代谢物的浓度都很低,尿中药物的浓度也很低。相对而言,尿中代谢物α-羟基三唑仑(α-hydroxytrizolam,简写为α-     

气相色谱-电子捕获检测器快速测定水产品中多种农药及兽药残留北大核心CSCD

称取2.000g样品,加入含0.2%(φ)甲酸的乙腈(85+15)溶液10mL,涡旋混合30s,振荡提取30min,以10 000r·min-1转速离心5min,取上清液。用2mL的含0.2%(φ)甲酸的乙腈(85+15)溶液活化Oasis PRiME HLB小柱后,将上述上清液全部通过Oasis PRiME HLB小柱并收集滤液,于50℃水浴下氮吹至干,加入100μL衍生化试剂[N,O-双(三甲基硅烷基)三氟乙酰胺-三甲基氯硅烷(质量比为99∶1)],涡旋10s,于65℃恒温反应30min后,于50℃水浴下氮吹至干,用正己烷定容至1.0mL,以DB-5/DB-35色谱柱(30m×0.25mm,0.25μm)分离11种拟除虫菊酯类农药和3种氯霉素类兽药,采用电子捕获检测器。11种农药的线性范围为0.10~0.80mg·L-1,3种兽药的线性范围为5.0~40mg·L-1,检出限(3S/N)在0.000 1~0.008 0μg·g-1之间。加标回收率为85.6%~119%,测定值的相对标准偏差(n=6)不大于9.0%。     

气相色谱-电子捕获检测法测定海水中十氯酮残留

通过考察提取溶剂、毛细管柱、净化条件及共溶出干扰物等因素对十氯酮测定的影响,建立了二氯甲烷液-液富集萃取、硫酸净化分离、气相色谱法(GC)-电子捕获检测器(ECD)测定海水介质中有机氯农药类持久性有机污染物十氯酮残留分析方法。1 L海水经50 mL二氯甲烷萃取富集,浓缩后采用硫酸净化,以1%(体积分数)甲醇/正己烷混合溶液转移定容后,采用DB-5非极性毛细管柱进行GC分离,电子捕获检测器可测定其中十氯酮的含量;该方法采用外标法定量,在5～100 μg/L范围内呈线性,线性相关系数为0.9989。低、中、高3个浓度水平的平均加标回收率为81%～108%,相对标准偏差为1.2%～5.1%(n=6)。方法的检出限为0.6 ng/L。结果表明,该方法灵敏度高,线性关系好,可以满足简便、快速、准确测定海水中十氯酮的要求。     

Analysis by electron oscillation in a conventional GC detector

The oscillation of electrons—as driven by AC polarization—can be used to extract a high-sensitivity signal from a conventional electron capture detector. For example, hexachloroethane was detected at a hypercoulometric ratio of 2.0 F/mol, down to ca. 60 fg/s (S/N=3) and with a linear range in excess of two orders of magnitude. The change in carrier gas from nitrogen to argon-methane produced the expected order-of-magnitude increase in optimum oscillation frequency. Anab initio simulation of potentials and ion populations in a heterogeneous electron capture system under a high-frequency AC regime provided further insight into the detector's mechanism: Hypercoulometric response is mainly caused by increased cation-electron recombination in the plasma region, owing to a decreased field gradient and an increased cation concentration.Material taken from doctoral thesis (Dalhousie University, 1987)     

A theoretical model of the electron capture detector

Summary This paper reports a theoretical model of the ECD detector. The model presented here can be used to examine the influence of pulse parameters on the current and signal characteristics of the detector. On the basis of this model it was found that a space charge is created in the detector when it is supplied with pulse voltage. Due to the electric potential generated by the space charge, in the time between the pulses the electrons and negative ions move towards the detector electrodes. The ionization current of the detector is the sum of the electron current flowing to the anode under the influence of the supplied pulse voltage and the current flowing under the space charge potential in the time between the pulses. It was also found that the detector signal is the sum of the differences between those two currents caused by introducing the sample molecules to the detector. The model was tested for a detector with different electrode configurations which worked at temperature of 300 K or 573 K and which was supplied with nitrogen or Ar+10% CH₄ as the carrier gas.     

超声辅助碱解萃取-气相色谱-电子捕获检测器测定海洋沉积物中8种多溴联苯醚

将超声辅助碱液分解杂质与溶剂萃取相结合,采用气相色谱-电子捕获检测(GC-ECD)建立了一种快速高效净化、萃取海洋沉积物中8种常见多溴联苯醚(PBDEs)的分析方法。样品在2.00 mol/L NaOH甲醇溶液中超声30 min,经正己烷萃取、单层硅胶净化、正己烷洗脱、旋蒸浓缩后定容至100 μL,采用GC-ECD分析。结果表明,PBDEs各单体的加标回收率为63.6%~110.3%,相对标准偏差(RSD)为1.7%~15.5%(n=5);十溴联苯醚(BDE-209)的检出限为0.097 ng/g,其他7种单体的检出限为0.002~0.011 ng/g(信噪比为3)。该方法的准确度和精密度较高,稳定性和回收率良好,可满足沉积物中PBDEs的分析要求。利用建立的方法测定了渤海表层沉积物中PBDEs的含量,8种PBDEs总含量在1.566~6.760 ng/g之间,其中BDE-209的含量为1.461~6.438 ng/g,总体呈现出由近岸向远岸递减的趋势,表明人为活动、表层冲刷和陆地河流的输入对渤海地区PBDEs的含量有重要影响。     

Evaluation of lipid removal from animal fats for the determination of organochlorine, pesticides, and polychlorinated biphenyl indicators by gas chromatography with electron capture detector

For cleanup of animal fat before GC analysis of organochlorine pesticides and polychlorinated biphenyls, freezing-lipid filtration with solid-phase extraction and matrix solid-phase dispersion were evaluated to replace the official Brazilian methodology that uses preparative alumina column chromatography. General drawbacks associated with this last technique, such as the use of large amounts of solvent, laborious and time-consuming procedure could be avoided by using these alternative approaches. Experiments were carried out to study the performance by using different combinations of sorbents and elution solvents. Efficiency of alternative extraction methods in terms of fat removal and recovery capability was monitored by gravimetry, TLC, and GC with electron capture detection. Freezing-lipid filtration with solid-phase extraction afforded better clean up efficiency with recoveries in a range of 54.5 to 103.6% with the relative standard deviation of less than 10% for all compounds under investigation.     

气相色谱法测定水中溴氰菊酯

采用气相色谱法-电子捕获检测器(GC- ECD)对水中溴氰菊酯进行检测.取10 mL水样,加入0.4g氯化钠,经环己烷萃取后,有机相干燥、氮吹浓缩,用带电子捕获检测器的气相色谱仪检测,外标法定量.结果表明,溴氰菊酯在2.0 ～40.0 μg/L范围内线性关系良好,相关系数为0.999 8.方法检出限为:0.40 μg/...     

A micro-volume electron capture detector for use in high resolution capillary column gas chromatography

A new design for an electron capture detector cell is described. The cell is compatible with the requirements of high resolution capillary columns and is shown to be useful in applications that require high analysis speed. A unique method of sample introduction reduces the problems of sample loss by adsorption on the surfaces of the cell. Previously reported problems of sample loss by adsorption on active surfaces within the cell when using hydrogen carrier gas are shown to have been eliminated. Examples are shown demonstrating the increased speed of analysis that can be obtained when using hydrogen carrier gas and 100 micron diameter columns.     

气相色谱-脉冲火焰光度法测定水产品中的二硫氰基甲烷残留

建立了气相色谱-脉冲火焰光度法(GC-PFPD)测定水产品中二硫氰基甲烷(MBT)残留的分析方法。用二氯甲烷-正己烷溶液(1∶1,v/v)在超声条件下提取水产品中的MBT,然后用中性氧化铝固相萃取小柱对提取物进行净化和富集,通过HP-5MS石英毛细管柱(30 m×0.32 mm×0.25μm)分离,最后采用配有脉冲火焰光度检测器的气相色谱仪进行测定,外标法定量。MBT在1.0~20.0 mg/L范围内线性关系良好,相关系数为0.997 1;检出限为0.1 mg/kg;加标回收率为65.6%~97.6%,精密度为6.32%~12.8%(n=7)。该法能很好地满足水产品中药物残留检测的需求。     

微型气相色谱仪热导检测器放大电路设计

Agilent公司生产的Agilent 3000+系列色谱仪是微型气相色谱仪(micro GC)的典型代表,其热导检测器的信号放大电路和模数转换器(analog-to-digital convertor, ADC)存在功耗大、工作温度过高等不足.文中分析了micro GC电路的功能需求,从选用低噪声的24 bit Δ-Σ ADC ADS1255入手,设计了高共模电压容限、低噪声的全差分放大电路及其他外围电路,并且对全差分放大电路建立了噪声模型,计算了其噪声理论值,优化了系统设计参数.另外,还设计了一个测试平台,对所设计的全差分放大电路和ADC的性能进行了全面的测试评估,结果表明新设计的热导检测器放大电路与ADC的总噪声(以美国材料与试验协会(ASTM)标准值计)仅为1.25 μV,总功耗降低了3.7 W,满足micro GC的功能需求,而且可靠性高、体积小、结构简单,可用于新一代micro GC的研发和生产.     

Electron capture detector response to low electron affinity aromatic hydrocarbons using positive ion stabilization and alkyl chloride sensitization

The electron capture detector (ECD) response to numerous aromatic hydrocarbons of low electron affinity (EA) is shown to be detrimentally affected by two processes which compete with and typically overwhelm the electron capture reactions of these molecules. It is shown that the effects of these two undesired reactions can be eliminated by the permanent addition of trimethylamine and one of several alkyl monochlorides to the detector make-up gas. These modifications of the detector gas result in greatly increased sensitivity, increased linearity, and increased reproducibility of response. A kinetic model for the ECD responses of low EA resonance capture molecules is developed which appears to explain these improvements.