农产食品中菊酯类农药残留量的气相色谱快速分析方法

1　前言菊酯类农药是一种广泛应用于农业和家庭防虫的化学品,由于具有杀虫谱广、施用量小、杀虫速效、持效期长而低残毒等特点,其使用愈来愈普遍[1]。本文介绍了用一根色谱柱同时测定食品中的菊酯类农残的快速分析方法,样品中的菊酯类农残经丙酮-石油醚萃取,用无水硫酸钠-中性氧化铝净化,加入活性炭粉脱色,用气相色谱-电子捕获检测器测定。其回收率范围为90.2%-109.1%,检测限范围为0.0005mg/kg-0.002mg/kg,能满足残留量分析的要求。2　实验部分[2-8]2.1　主要仪器和试剂2.1.1　仪器岛津GC-7AG气相色谱仪附电子捕获检测器(ECD)、高速组织…     

快速气相色谱法测定蔬菜中菊酯类农药残留量

采用一种较快速，简单的方法测定蔬菜中菊酯类农药残留物。样本中农残经乙酸酯萃取，凝胶渗透色谱及固相提取净化后，用气相色谱－电子捕获检测器测定，色谱柱为ＨＰ－５小口长石英毛细管柱。本法对６种常用菊酯类农药的回收率范围为８９．６％－９９．７％，检测限为０．０４ｍｇ／ｋｇ。对同一批普施用菊酯类农药的白菜样本进行化验，本法跟美国食物及药品管理局农药残留标准测定方法所得结果非常吻合。     

气相色谱-电子捕获检测器同时测定茶叶中有机氯及拟除虫菊酯类农药残留

在超声波辅助下,以正己烷-二氯甲烷（1：1,V／V）混合溶剂提取样品,提取液用弗罗里硅土和中性氧化铝混合柱净化,用气相色谱-电子捕获检测器（GC-ECD）同时测定茶叶中18种有机氯和9种拟除虫菊酯类农药残留。有机氯农药在0.001-0.2μg／mL,拟除虫菊酯类农药在0.005-1.0μg／mL范围内线性良好。有机氯农药在0.04、0.01μg／mL两个添加水平的回收率分别为89.5％-113.2％和80.0％-112.7％,相对标准偏差分别为3.82％-9.64％和5.32％-13.8％。拟除虫菊酯在0.2、O.05μg／mL两个添加水平的回收率分别为97.5％-129.6％和87.3％-110.2％,相对标准偏差分别为3.78％-10.72％和3.02％-13.84％。本方法快速、灵敏、准确、可靠,用于江西茶叶样品中有机农药残留测定,获得较好结果。     

固相萃取-气相色谱法测定茶叶中多种有机磷农药

建立了固相萃取-气相色谱法同时测定茶叶中16种有机磷农药残留的方法.样品用丙酮超声提取后,经自制的N-丙基乙二胺(PSA)/活性炭固相萃取柱净化,以混合溶剂乙腈/甲苯(V(乙腈):V(甲苯)=1:3)洗脱,采用气相色谱-氮磷检测器(GC-NPD)测定.方法的回收率在62.8%～109.1%之间,相对标准偏差小于14.7...     

气相色谱法测定桂皮中毒死蜱农药残留量

介绍了用气相色谱法检测毒死蜱农药在桂皮中的残留方法,选用Agilent 6890N气相色谱仪,DB-1701和HP-5双柱法、火焰光度检测器(FPD)和电子俘获检测器(ECD)双检测器来定性,外标法定量,并采用中性氧化铝柱净化样液,效果良好,节约检测成本,回收率为86.7%～93.4%,各项指标均满足有关要求.     

气相色谱-质谱法测定乳制品中17种拟除虫菊酯农药残留方法的研究

研究了选择离子气相色谱-质谱法测定乳及乳制品中2,6-二异丙基萘、七氟菊酯等17种拟除虫菊酯类农药残留的方法,优化了预处理方法和气相色谱-质谱分析条件.乳制品以乙腈为提取溶剂,采用匀浆提取,经C18及氟罗里硅土固相萃取小柱净化,采用气相色谱-质谱法测定和确证,选择离子监测模式,外标法定量.结果表明,17种农药在0.01 ～1.00 mg/L范围内呈线性关系,在0.01 ～0.2 mg/kg范围内的加标回收率为76% ～114%,相对标准偏差为7.0% ～16.2%,检出限为0.002 ～0.010 mg/kg,定量下限为0.010 ～0.030 mg/kg,方法能满足国内外乳制品中菊酯类农药残留限量水平的要求.     

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。     

基质固相萃取-气相色谱电子捕获检测器同时测定大米中12种有机氯农药残留量

建立了大米中12种有机氯农药气相色谱-电子捕获检测器检测方法.采用基质固相分散(Matrix Solid Phase Disperse, MSPD)技术进行样品前处理, 用气相色谱-电子捕获检测器进行快速定性定量分析.基质固相分散集提取、过滤、净化于一步完成, 避免了样品均化、转溶、乳化、浓缩造成的待测农药组分的损失, 大大提高了方法的准确度和精密度.12种有机氯农药的添加回收率在83%～103%之间,相对标准偏差为2.2%～19%.     

气相色谱法测定苹果中的多种农药残留量

采用丙酮和正己烷提取,C18固相萃取小柱净化,气相色谱法用电子捕获检测器（GC-ECD）测定,建立了苹果中有机氯、拟除虫菊酯和有机磷3类15种农药的同时检测方法.该方法的回收率为78.3%～104.2%、相对标准偏差≤6.2%.     

大口径毛细管柱气相色谱测定烟草中6种拟除虫菊脂农药残留量

报道了用大口径毛细管柱气相色谱同时测定烟草中甲氰菊脂、三氟氯菊脂、氯菊脂、氯氰菊脂、氰戊菊脂、溴氰菊酯6种拟除虫菊脂农药残留量的方法。样品农药残留经丙酮提取,凝结液除杂,石油醚萃取,弗罗里硅土柱净化,OV-101大口径毛细管柱分离,电子捕获检测器（ECD）检测。本法的检出限为 0.001-0.005mg/kg。6种农药标准加入回收率为85.5%-102.0%,相对标准偏差4.6%-17.5%.     

A photoionization detector

Summary A photoionization detector (P.I.D.) with separated discharge and detection compartments, enabling detection of eluted substances under normal pressure, has been developed. A detection mechanism was formulated for these conditions and relations for the P.I.D. signal were derived. The detector can measure all substances with ionization potentials less than 11.4 eV. A detection limit of 10^–14 mol/s for benzene, with a linear dynamic range of 10⁴, was attained.     

Combination of amperometric detector & UV detector for capillary electrophoresis

A new electrochemical cell assembly with the combination of UV and amperometric detector (AD) based on their complementarity was described. A Nafion tubing junction was used to decouple the high voltage from the separation capillary in the rear of on-column UV detector. In this mode, the electroactive and inert compounds could be detected by UV and AD at the same time. Aromatic amines were determined with the UV and the end-column AD detection to evaluate the performances of the cell assembly. Such an improved electrochemical detector could match the capillary with different diameters. By simple adjustment of the screws, the positioning of the working electrode and the detection capillary was easily gained without microscope. It is also very easy to assemble and disassemble the working electrode when needed.     

Pulsed discharge emission detector: an element-selective detector for gas chromatography

An element-specific pulsed discharge emission detector (PDED) has been coupled directly with a vacuum UV monochromator so that vacuum UV atomic emissions from Cl, Br, I and S can be observed. The observed sensitivities for the elements are in the range of mid to high pg/s, but can be lowered by direct absorption of the radiation using a vacuum UV radiation photomultiplier tube. A helium pulsed discharge photoionization detector (He-PDPID) was run simultaneously in parallel with the PDED. The chromatograms recorded with the two detectors had similar peak shapes, suggesting that there is no peak tailing in the PDED. The ratio of the detector responses PDED/He-PDPID can be used for qualitative identification of the Cl-, Br-, I- or S-containing compounds.     

A radio-frequency moving-boundary detector

A new type of moving-boundary detector is described in which boundaries are detected at platinum ring electrodes situated on the outside of a moving-boundary tube. These rings are part of a bridge circuit operating at radio frequencies. Impedance changes in the region of the rings are converted by a phase-sensitive detector to a voltage output which, when operating in the differential mode, takes the form of a sharp peak as a boundary passes through the rings. Boundary displacements of less then 20 m can be detected, and a precision of better than 0.02% is obtained in the measurement of boundary velocities in typical transference measurements. The fact that only three electrical leads are required in the detecting circuit gives this detector a decided advantage for high-pressure work. Equally important is the elimination of electrode polarization problems associated with other types of electrical detectors.Taken, in part, from a Ph.D. thesis, Carnegie-Mellon University, 1971.     

Directional characteristics of a detector

Some rarely used detector characteristics which characterize the directional properties of a detector are introduced in the paper. Attention is particularly paid to relative and absolute directiveities of a detector and their connection to other important detector characteristics.