Evaluation and comparison of selective gas chromatographic detectors for the analysis of pesticide residues

Summary A series of studies is described on the evaluation and comparison of some selective gas chromatographic detectors used in pesticide residue analysis. A detailed study of the optimization and response characteristics of the CsBr and RbCl three-electrode alkali flame ionization detector for N and P compounds, the Coulson electrolytic conductivity detector in the nitrogen, sulphur and pyrolytic modes of operation and the sulphur phosphorus emission detector, a type of flame photometric detector, was carried out to obtain maximum sensitivity and reliability for the analysis of pesticide residues in various biological substrates. It was observed that the alkali flame and electrolytic conductivity detector responses to nitrogen compounds were of the same order, while the electrolytic conductivity detector was more sensitive than the flame photometric detector to sulphur compounds. Also, attempts were made to correlate the responses from these different detector systems using the insecticide chlorpyrifos which contains P, S, Cl and N atoms. The use of chlorpyrifos as an evaluation standard in verifying the acceptable performance of these types of detectors is recommended.Chemistry and Biology Research Institute Contribution No 901     

Glass capillary gas chromatography with simultaneous flame ionization (FID) and Hall® element-specific (HECD) detection

Two glass capillary gas chromatographic systems were equipped with inert effluent splitters which allowed simultaneous data acquisition using nonspecific and element-specific detectors. Simultaneous detection was achieved using the nonspecific flame ionization detector (FID) and the Hall^® electrolytic conductivity detector (HECD) operated in either the sulfur-or the nitrogen-specific mode. Typical application of the simultaneous detection system as applied to analysis of petroleum residues is briefly described. The Hall electrolytic conductivity detector can be made element specific for halogen-, sulfur-, or nitrogen-containing compounds. Simultaneous detection enhances the information yield from a single sample injection and proves to be a powerful complementary technique when used with computerized gas chromatography/mass spectrometry.     

气相色谱法测定茶叶中多种有机磷农药残留量

 采用微量化学法和全自动固相萃取技术 ,建立了气相色谱法同时测定茶叶中 14种有机磷农药残留量的方法 ,并对样品的前处理作了一定的探讨。结果表明 ,采用程序升温 ,所测定的 14种有机磷农药在SPBTM 170 1石英毛细管柱上得到了很好的分离 ,且方法快速、灵敏 ,完全符合实际应用需要。     

气相色谱法测定茶叶中的噻嗪酮、甲胺磷、乙酰甲胺磷及三唑磷残留

建立了同时测定茶叶中噻嗪酮、甲胺磷、乙酰甲胺磷和三唑磷4种农药残留量的测定方法。在45 ℃加温条件下,用乙酸乙酯-正己烷混合溶剂提取及活性炭色谱柱净化,用不同配比的乙酸乙酯-正己烷混合液梯度洗脱待测组分,以DB-210毛细管色谱柱分离、氮磷检测器测定。结果表明,上述4种农药在10 min内能很好地分离;样品加标回收率(n=3)为73.4%~96.9%。方法的变异系数为2.49%~3.35%,茶叶（干重）中4种农药的定量检测下限为7.0~12.0 μg/kg。     

气相色谱-负化学离子源质谱法在食品安全分析中的应用

气相色谱-负化学源质谱法(GC-NCI-MS)技术被广泛应用于环境、人体组织、食品等样品中污染物的定性分析和定量测定.综述了近年来气相色谱-负化学源质谱技术在食品安全分析如农药残留、兽药残留和污染物测定中的应用.     

毛细管气相色谱法测定食品、中药中的有机氯农药

建立食品和中药中有机氯农药残留量的毛细管气相色谱检测方法。样品经有机溶剂超声提取,硫酸净化,采用OV-1701毛细管柱,不分流分流进样,程序升温分离,电子捕获检测器检测,外标法定量,平均回收率为84.3%~100.6%,RSD为1.28%~3.56%。该法操作简便,重复性及分离效果好。     

Multiresidue procedures for the determination of chlorinated dibenzodioxins and dibenzofurans in a variety of foods using capillary gas chromatography-electron-capture detection

Multiresidue digestion-extraction procedures for the determination of chlorinated dioxins and furans in a wide variety of products are presented. Procedure selection is dependent upon the residue(s) of interest, and on the fat content of the product. Additional cleanup is accomplished using column chromatography and a Florisil trap. The separation of residues is achieved by fraction collection off of two high-performance liquid chromatographic systems. Capillary gas chromatography employing electron-capture detection is used for quantitation. The extracts are suitable for gas chromatography mass spectrometry or gas chromatography with Hall electrolytic conductivity detection. Results of analysis, recovery data, and interlaboratory comparisons are presented. Spike recoveries will typically average 90% +/- 10%.     

亲水作用液相色谱脱除人参提取物中农药残留

亲水作用液相色谱法(HILIC)是一种用于改善强极性物质的保留和分离选择性的方法,广泛应用于药物分析、代谢组学、蛋白质组学等领域。该文利用农药分子与皂苷成分在HILIC上的保留行为差异,开发了一种农药残留脱除方法。以市售高纯人参提取物为例,该文评价了农药分子和人参皂苷在亲水色谱柱上的保留行为,并考察了上样量、淋洗体积、上样体积等因素对农残脱除效果的影响。实验结果证明:7种人参皂苷由于糖链上的羟基与亲水色谱固定相上的羧基形成氢键作用而具有较强保留,而农药分子由于亲水性较差且相对分子质量较小,保留很弱,从而一步实现了7种人参皂苷的富集与14种农残的脱除。在优化所得的最佳脱除工艺条件下,最终制备得到的人参总皂苷样品中,总皂苷的含量由59.87%提高到69.61%;总皂苷的回收率为94.4%;通过气相色谱-三重四极杆质谱(GC-MS/MS)对样品中的农残进行定量检测,发现原人参提取物中14种农残均得到了有效脱除,其中5种含量降至0.05 mg/kg以下,9种完全脱除。本研究是亲水色谱在中药提取物中农残脱除领域的应用,为天然产物的精制提供了一种新的技术手段,该技术对人参提取物中的农残脱除率高、人参总皂苷回收率高且安全、高效、无污染,为高品质人参提取物的研制提供了新的思路。     

茶叶中有机氯和拟除虫菊酯多种农药残留同时分析的样品前处理研究

建立了茶叶中同时分析12种有机氯和拟除虫菊酯类农药残留的样品提取和固相萃取(SPE)前处理方法.试样在超声条件下用正己烷提取后用自制弗罗里圭(florisil)/石墨化碳复合固相萃取小柱净化,然后采用气相色谱-电子捕获检测器(GC-ECD)测定.研究结果表明,当茶叶中农药加标在4.93～201.00 ng/g范围内时,添加回收率为68.9%～112.2%,相对标准偏差为2.43%～15.8%,方法的检出限范围在2.52～10.59 ng/g.     

高效液相色谱法分析水稻和稻田中的氯硝柳胺乙醇胺盐残留

建立了高效液相色谱(HPLC)测定水稻和稻田中氯硝柳胺乙醇胺盐残留量的分析方法。稻田水和稻秆样品中的氯硝柳胺乙醇胺盐残留用碱性乙酸乙酯直接提取;而稻田土壤、糙米和谷壳样品则先经碱性乙醇提取,再用乙酸乙酯进行萃取。萃取物经弗罗里硅土柱净化后,经Welchrom C18柱分离,采用紫外检测器检测,外标法定量。在0.01～10.00 mg/L范围内,氯硝柳胺乙醇胺盐的峰面积与其质量浓度间呈良好的线性关系,相关系数为0.9998。在稻田水、土壤、稻秆、糙米和谷壳中添加0.01～5.00 mg/kg的氯硝柳胺乙醇胺盐,其平均回收率为93.47%～100.9%,相对标准偏差为1.46%～5.82%,符合农药残留量分析与检测的技术要求。该方法简便、快速,灵敏度高,重现性好,可用于环境系统中氯硝柳胺乙醇胺盐残留量的分析与检测。     

气相色谱法测烟草中拟除虫菊酯和有机磷类农残

建立了一种测定烟草中拟除虫菊酯类农药和有机磷类农药残留量的气相色谱法.用普通的聚苯乙烯凝胶柱代替昂贵的凝胶渗透色谱仪;层析柱填料用弗罗里硅土代替硅胶;用工作标准溶液过柱曲线作为标准曲线;有机磷类农药气相检测器用PFPD代替FPD.方法的检测量为0.01μg/g～0.04 μg/g,平均加标回收率为70.18%～95.86%,RSD为4.36﹪～9.96﹪,对样品进行了拟除虫菊酯类农药和有机磷类农药残留量的测定,结果满意.     

The automated determination of volatile organic contaminants in ambient air and/or soil gas by gas chromatography with selective detectors

Two systems have been developed which are suitable for the determination of sub parts per billion levels of organic contaminants in ambient air and soil gas. Gas samples are passed through an adsorbent where the contaminants are trapped. Following thermal desorption the contaminants are quantitated by capillary GC employing photoionizations electrolytic conductivity, and electron capture detection. The performance of the systems is described in detail.     

高效液相色谱-串联质谱法测定食品中20种氨基甲酸酯类农药残留

建立了食品中20种氨基甲酸酯类农药残留量的高效液相色谱-串联质谱联用(HPLC-MS/MS)测定与确证方法。20种氨基甲酸酯类农药在0.005～0.1 mg/kg范围内线性良好,相关系数为0.991 7～0.999 6;在0.005～0.025 mg/kg范围内, 20种目标物的回收率为51.2%～125.0%,相对标准偏差为1.4%～19.8%。该方法准确、灵敏、快速,可满足国际上对食品中这20种氨基甲酸酯类农药残留量的检测需要。     

Chromatographic methods for the determination of pesticides in foods.

Chromatography is the most important technique available to the analyst dealing with the determination of pesticide residues in food, feed and environmental samples. Numerous methods for pesticide residues in foods have been developed in the past few years, and this paper reviews some of the most important procedures. A great variety of chromatographic methods, such as solid-phase extractions, column chromatographic clean-up methods, thin-layer, gas, high-performance liquid and supercritical fluid chromatography, and their coupling with sensitive and selective detection methods are surveyed.     

固相萃取气相色谱-质谱法测定蔬菜中含氮杂环农药残留

建立了固相萃取（SPE）气相色谱-质谱（GC-MS）同时测定蔬菜中敌菌灵、噻菌灵、氟虫腈和噻嗪酮4种含氮杂环农药残留量的分析方法.蔬菜样品用乙腈匀浆提取后经弗罗里硅（Florisil）固相萃取柱净化.采用GC-MS检测,在选择离子检测（SIM）模式下以特征离子定量,用全扫描（SCAN）方法确证.方法具有良好的线性关系（R≥0.9953）和重现性（峰面积RSD≤9.1%）,最低检出限（S/N=3）在3.6~1.8×10-4μg/mL之间,4种农药添加回收率在76.1%~116.4%之间,RSD≤9.8%,用于实际样品菜心的检测,结果满意.方法操作简单,灵敏度高,可作为测定各种蔬菜基质中含氮杂环农药残留量的确证方法.     

气相色谱-柱后分流-反吹技术测定含脂羊毛中有机氯和有机磷类杀虫剂残留

建立了同时测定含脂羊毛中20种有机氯和有机磷类杀虫剂残留的气相色谱-柱后分流-反吹检测方法.通过二氧化碳超临界萃取技术提取含脂羊毛样品中的杀虫剂残留并经中性氧化铝固相萃取柱净化,采用气相色谱-柱后分流技术,可以同时得到3个检测器信号(MSD、μECD和NPD),可对两类杀虫剂准确定性和定量分析.同时运用反吹技术,减少样品中高沸点杂质对色谱系统的污染.3个添加水平的回收率为85.6%～120.9%,相对标准偏差在1.2%～17.3%之间.方法干扰小、重现性好、自动化程度高,能够对含脂羊毛中有机氯和有机磷类杀虫剂残留准确地定性定量分析.     

微波辅助提取-气相色谱法同时测定中草药中有机磷和氨基甲酸酯农药残留

建立了中草药中有机磷和氨基甲酸酯类农药同时检测的气相色谱分析新方法.中药材试样依据正交实验的优化条件,用正己烷-丙酮(1∶4,V∶V)混合提取剂进行微波辅助提取,经弗罗里硅土和中性氧化铝混合层析柱净化后,采用HP-5毛细管柱分离,氮磷检测器同时检测中草药中15种有机磷和6种氨基甲酸酯类农药残留量.21种农药在0.01～1.0 mg/L的浓度范围内线性良好,线性相关系数为0.9950～1.000,检出限为0.002～0.01 mg/L.在0.05、0.2、0.5 mg/kg三个添加水平的平均回收率分别为75.11%～128.57%、75.85%～120.71%和76.43%～117.25%,相对标准偏差分别为 3.10%～10.58%、5.27%～9.94%和4.03%～9.03%.方法用于中草药中有机磷和氨基甲酸酯类农药残留的同时检测,结果良好.     

毛细管气相色谱法测定芝麻中多种有机磷农药残留量

建立了芝麻中多种有机磷农药残留量的毛细管气相色谱的测定方法。样品以V(乙腈 )∶V(丙酮 ) =1 0∶1混合溶剂为提取剂 ,应用超声波辅助提取 ,固相吸附层析柱净化m(中性氧化铝 )∶m(弗罗里硅土 ) =1∶1 ,采用GC FPD法同时测定芝麻中的多种有机磷农药残留量。检出限为 0 .0 1 1～ 0 .0 1 7μg mL。方法的回收率为 82 .1 %～ 1 0 9.7%。     

Graphene and graphene like 2D graphitic carbon nitride: Electrochemical detection of food colorants and toxic substances in environment

Excessive consumption of substances such as food colorants, exposure to doses of metal ions, antibiotic residues and pesticides residues above maximum tolerance limit have a detrimental effect on human health. Hence in detecting these harmful substances, the development of sensitive, selective and convenient analytical tools is an essential step. Graphene and graphene like 2D graphitic carbon nitride have shown great promise in the development of electrochemical sensors for determining the levels of these substances in different samples. In this paper, graphene and graphene like 2D graphitic carbon nitride applications on the determination of various food colorants in foods and drinks such as azo dyes (tartrazine, allura red, amaranth, carmine and sunset yellow); metal ions contaminants, antibiotic and pesticide residues in the environment are reviewed.