Development of IC-ELISA for detection of organophosphorus pesticides in water

Diethyl (carboxymethyl) phosphonate (DECP) was used as the hapten to develop an indirect competitive enzyme-linked immunosorbent assay (IC-ELISA) for detecting organophosphorus pesticides (OPs). Conjugator of DECP with bovin serum albumin (BSA) was used as the immunogen for producing the polyclonal antibodies (PcAbs). Three antisera were obtained after the immune procedure. Characterization studies of the PcAbs indicated that the titer of antiserum-1 was highest in 3 antisera, and antiserum-1 had high affinity and specificity to the parathion, dichlorvos and pirimiphos. The IC-ELISA showed an IC₅₀ of 0.428 μ g/mL with a detection limit of 0.0125 μ g/mL to parathion. The assay also indicated that the IC₅₀ values of pirimiphos and dichlorvos were 0.331 μ g/mL and 1.25 μ g/mL respectively, and the detection limits of pirimiphos and dichlorvos were 0.0116 μ g/mL and 0.048 μ g/mL respectively. Recoveries of parathion, pirimiphos and dichlorvos spiked into water samples ranged from 90% to 160%. The results indicated that the ELISA could be a convenient and supplemental analytical tool for monitoring OPs residues in environmental water samples.     

Oxidation of organophosphorus pesticides for the sensitive detection by a cholinesterase-based biosensor

A potentiometric flow injection-type biosensor developed in our laboratory was used for the determination of organophosphorus pesticides (OPs). The principle of the biosensor is that the degree of inhibition of a sensor enzyme by an OP is dependent on the concentration of the pesticide. The sensor system consisted of a reactor with acetylcholinesterase (AChE) immobilized on a controlled pore glass and a detector with a tubular H(+)-selective membrane electrode. In order to examine the possibility of enhancing the sensitivity of the sensor by converting OPs to oxidized forms (stronger inhibitors), a comparison of the degree of enzyme inhibition by OPs at 10(-6) M before and after their oxidation was made. All of the ten pesticides tested exhibited greater inhibitory power toward the sensor enzyme following oxidation. All of the oxidized pesticides at 10(-6) M inhibited the sensor enzyme to a considerable degree, demonstrating the utility of the developed method for the class-specific determination of OPs. A calibration curve for diazinon, over the concentration range of 10(-11)-10(-4) M, was obtained. The lower detection limit was 2 x 10(-10) M. Treatment of the inhibited enzyme with pyridine-2-aldoxime restored the enzyme to near full activity, allowing repeated use of the sensor.     

饮用水源中有机磷农药的应急预处理技术研究

有机磷农药的大量生产和使用对饮用水安全造成了潜在的巨大威胁。为了在饮用水源突发有机磷农药污染时保证饮用水安全,在水源水中进行了高锰酸钾氧化、粉末活性炭（PAC）吸附、臭氧氧化、O3／PAC和O3／H2O2 5种预处理技术对4种有机磷农药（乐果、敌敌畏、马拉硫磷和甲基对硫磷）的去除效果对比研究。实验结果表明,当水中乐果、敌敌畏浓度为266肛g／L、3．6μg／L时,0．5mg／L的高锰酸钾不能将其去除达标（国家生活饮用水卫生标准,GB5749—2006）;PAC对乐果和敌敌畏的吸附效果良好,20mg／L的PAC能将低浓度的乐果（241μg／L）和中低浓度的敌敌畏（3．0～9．3μg／L）去除达标;臭氧对4种农药均有较好的去除效果,当CT（浓度×时间）值为17mg·min／L时,除高浓度的乐果（729μg／L）和甲基对硫磷（276μg／L）外,其余农药均可以去除达标;采用O3／PAC和O3／H2O2高级氧化预处理,高浓度的乐果（629～710μg／L）和甲基对硫磷（364～428μg／L）均可迅速去除达标。     

Effects of cyclodextrins on photodegradation of organophosphorus pesticides in humic water

Cyclodextrin (CyD) effects on photodegradations of organophosphorus pesticides in humic water were monitored on the basis of the increase percentage of the photodegradation rate constant for CyD-containing humic water. Remarkable promotion effects of CyDs were observed in humic water for photo-induced radical generation. The promotion effects could be mainly assigned to the inclusion effects of CyDs to catalyze interactions of pesticides with reactive radicals generated by the humin photosensitizer and inclusion-trapped in CyDs.     

Comparison between solid-phase extraction methods for the chromatographic determination of organophosphorus pesticides in water

A solid-phase microextraction (SPME) procedure has been developed to extract eight organophosphorus pesticides (OPs) in water and the method was compared with a conventional solid phase extraction (SPE) technique. The extracted OPs were analyzed by gas chromatography using thermionic specific detection. Both extraction methods presented linear calibration at least over the concentration range investigated (100 to 1000 ng x mL(-1) for SPE and 1 to 100 ng x mL(-1) for SPME). SPME method presented higher sensitivity than SPE. The quantitation limits were between 0.1 to 1.0 ng x mL(-1) for SPME depending upon the analyte, and 100 ng x mL(-1) for SPE. The precision, as measured by the standard deviations (RSD), were in the range 3.6% to 5.8% for SPME and 2.4% to 9.2% for SPE. Along with the feature of being a solvent - free sampling technique, SPME offers additional benefits due to its high sensitivity, simplicity, and small size sample required (typically: SPE - 500 mL, SPME - 5 mL).     

Residues of organochlorine and organophosphorus pesticides in sugarcane crop soils and river water

The presence of residual organochlorine and organophosphorus pesticides was evaluated at different periods of sugarcane cultivation in agricultural soil and water samples from the town of Tlaltizapan, which is located in the state of Morelos in Mexico, to determine the presence and persistence of these compounds and their possible effects on the region. The compounds p,p′-DDE, p,p′-DDD (metabolites of p,p′-DDT), γ-HCH and heptachlor were found in more of 95% of the sampling zones in the three monitoring periods performed along 2 years. The highest concentration detected (129.6 μg/kg _{dry soil}) was for α-HCH, but its frequency of detection was ～5%. The low detection frequency of α-HCH and the high concentration values of γ-HCH indicate the repeated use of technical-grade HCH and Lindane (γ-HCH) in the region. Among the organophosphorus pesticides, ethyl parathion was the compound with the highest soil concentration, at ～2000 μg/kg_{dry soil}, during the initial monitoring. However, this compound was detected in the second monitoring with a concentration of ～4 μg/kg_{dry soil}, but it was not detected in the third, indicating that is was not accumulated in the environment. The heptachlor was the compound most commonly found in all water samples, within a range of 0.45–1.25 ng/L. The presence of this organochlorine compound in the water samples indicated a possible migration from the soil to water bodies due to soil erosion. The presence of organophosphorus compounds was not detected in the water samples, which could be attributed to the moderate persistence of these compounds and their consequent degradation before arriving at the water bodies.     

Improved silica gel cleanup method for organophosphorus pesticides

Quantitative recovery of some organophosphorus pesticide residues has not been possible with existing silica gel-cleanup procedures. We have developed a modification that permits quantitative recovery of all organophosphorus pesticides tested except those with a carbamate functional group. The method uses a 3.5 g silica gel column with a 1% acetic acid wash to condition the column prior to the addition of the sample. Percentage recovery and standard deviation of compounds such as phorate and disulfoton are 96 (5.6) and 98 (1.0) respectively. Recoveries range from 92 to 101% for the 11 compounds tested.     

Occurrence and risk evaluation of organophosphorus pesticides in typical water bodies of Beijing,China

Environmental Science and Pollution Research - Abstract Human activities, particularly in large cities, can lead to pollution caused by micropollutants such as pesticides in water bodies, which...     

高级氧化技术降解水中有机磷农药的研究进展

综述了近年来发展迅速的高级氧化技术,主要包括臭氧高级氧化技术、光催化氧化法、超声降解法、电化学水处理技术和超临界水氧化法等.结合有机磷农药废水处理方法的进展,介绍了各种高级氧化技术在机理研究和应用方面取得的成果和存在的问题,并指出了高级氧化技术在有机废水处理方面所具有的潜力.     

一种有机磷农药单克隆抗体的制备及其特性研究

合成与有机磷农药化学结构相近似的一类半抗原,制备该类半抗原的特异性单克隆抗体,建立酶免疫分析方法,并对4种有机磷农药(毒死蜱、甲基对硫磷、辛硫磷及三唑磷)进行检测.结果显示,此方法对部分有机磷农药灵敏度高,可以简便、快速地检测具有特定结构的有机磷农药,检测灵敏度与被检有机磷农药的化学结构相关.     

Evaluation of pressurized liquid extraction for determination of organophosphorus and pyrethroid pesticides in soybean

The purpose of this study was to develop an analytical method for the determination of organophosphorus and pyrethroid pesticides in soybean by pressurized liquid extraction (PLE). Two organic solvents, acetone and acetonitrile, were evaluated as extraction solvents. In both cases, the amount of extract was enhanced with increasing extraction temperature. The extracts obtained using acetonitrile were measured by gas chromatography/mass spectrometry after a cleanup process based on the analytical method for the Japanese Positive List System for Agricultural Chemicals Remaining in Foods. The effect of extraction temperature (range: 40– 130°C) on extraction efficiency was evaluated by a recovery study using 21 organophosphorus pesticides and 10 pyrethroid pesticides as target analytes and acetonitrile as the solvent. The results indicated that at 130°C, some organophosphorus pesticides might be degraded, whereas extraction temperatures between 70°C and 100°C were optimal. Next, a prepared sample containing fenitrothion and permethrin was analyzed. Although the sample was not soaked in water prior to analysis, PLE provided analytical results comparable to those obtained by solvent extraction with homogenization. Therefore, PLE is considered a simple and alternative technique for the extraction of organophosphorus and pyrethroid pesticides in soybean.     

Evaluation of pressurized liquid extraction for determination of organophosphorus and pyrethroid pesticides in soybean

The purpose of this study was to develop an analytical method for the determination of organophosphorus and pyrethroid pesticides in soybean by pressurized liquid extraction (PLE). Two organic solvents, acetone and acetonitrile, were evaluated as extraction solvents. In both cases, the amount of extract was enhanced with increasing extraction temperature. The extracts obtained using acetonitrile were measured by gas chromatography/mass spectrometry after a cleanup process based on the analytical method for the Japanese Positive List System for Agricultural Chemicals Remaining in Foods. The effect of extraction temperature (range: 40- 130°C) on extraction efficiency was evaluated by a recovery study using 21 organophosphorus pesticides and 10 pyrethroid pesticides as target analytes and acetonitrile as the solvent. The results indicated that at 130°C, some organophosphorus pesticides might be degraded, whereas extraction temperatures between 70°C and 100°C were optimal. Next, a prepared sample containing fenitrothion and permethrin was analyzed. Although the sample was not soaked in water prior to analysis, PLE provided analytical results comparable to those obtained by solvent extraction with homogenization. Therefore, PLE is considered a simple and alternative technique for the extraction of organophosphorus and pyrethroid pesticides in soybean.     

Headspace solid phase microextraction method for determination of triazine and organophosphorus pesticides in soil

A headspace solid phase microextraction method (HS-SPME) for simultaneous determination of five pesticides belonging to triazine and organophosphorus pesticide groups in soil samples was developed. Microextraction conditions, such as temperature, extraction time and sodium chloride (NaCl) content were investigated and optimized using 100 μ m polydimethyl-siloxane (PDMS) fiber. Detection and quantification were done by gas chromatography-mass spectrometry (GC-MS). Relative standard deviation (RSD) and recovery values for multiple analysis of soil samples fortified at 30 μ g kg^{? 1} of each pesticide were below 13 % and higher than 70 %, respectively. Limits of detection (LOD) for all the compounds studied were less than 3.2 μ g kg^{? 1}. The proposed method was applied in the analysis of some agricultural soil samples.     

Simultaneous determination of organophosphorus and organonitrogen pesticides residues in Angelica sinensis

Gas chromatography with nitrogen phosphorus detector (GC-NPD) was applied to the simultaneous determination of 15 organophosphorus and 6 organonitrogen pesticides residues in Angelica sinensis. The pesticides were extracted by microwave-assisted extraction (MAE) and ultrasound-assisted extraction (UAE) techniques, respectively. The experimental variables were optimized through orthogonal array experimental design. Cleanup of extracts was performed with column chromatography using florisil and neutral aluminum as the sorbents. The determination of pesticides in the final extracts was carried out by GC-NPD. Under optimized conditions, the average recoveries obtained from MAE and UAE are in the range of 75.1–129% and 70.6–129%, respectively, and the relative standard deviations of MAE and UAE were 3.1–10.6% and 1.0–17.8%, respectively.     

有机磷农药残留检测技术研究进展

综述了近年来有机磷农药残留检测技术的研究进展,其检测方法主要有色谱法、降解酶法、化学发光技术和生物传感技术.详细介绍了几种生物传感器(如酶传感器、微生物传感器、免疫传感器、压电传感器、纳米传感器和液晶型化学传感器)在有机磷农药检测中的应用,并展望了这一领域的发展趋势.     

利用基因工程菌BL21处理有机磷混合农药废水的研究

研究了悬浮状态和固定化状态的基因工程菌BL21对有机磷混合农药废水的降解特性.工程菌能快速、高效地降解有机磷混合农药,其最适底物是对硫磷,而马拉硫磷不能被工程菌降解.不同农药降解速率的差别造成了不同有机磷农药的降解过程需要用不同的动力学模型来描述.比较固定化状态和悬浮状态的工程菌的降解效果可知,固定化工程菌的降解活性较后者明显降低,其比降解速率大约仅为后者的20%.考察固定化工程菌长期运行的效果,发现其降解活性保存良好,工程菌稳定性大大提高,未出现固定化细胞溶涨、破碎现象.固定化后,工程菌的比降解速率虽然比悬浮工程菌降低了,但固定化工程菌更适用于长期运行的废水处理系统.     

Preservation of organophosphorous pesticides in water samples

Abstract

Four techniques were studied for capacity to preserve sixteen organophosphorous pesticides in distilled water and in creek water. A technique using chloroform effectively preserved all sixteen pesticides for the three weeks of the study and refrigeration was effective for fourteen of the pesticides, but buffers of pH A and pH 7 appeared undependable as preservatives.     

Analysis of organophosphorus pesticides in whole milk by solid phase microextraction gas chromatography method

Solid phase microextraction (SPME) was used for the extraction of residual coumaphos and dichlorvos in whole milk. The residues were analyzed by capillary gas chromatography equipped with nitrogen phosphorus detector (GC-NPD). A manual SPME holder with a 100-microm polyacrylate fiber was used. The optimized conditions for extraction by SPME method were: sample agitation, absorption temperature of 30 degrees C, absorption time of 40 min, desorption time of 10 min, and sample volume was 16.0 mL in the vial. Under these conditions, the calibration graphs were linear in the range of 0.17 microgL-1 to 1.75 microgL-1 for coumaphos and 0.69 microgL-1 to 6.90 microgL-1 for dichlorvos. Precision was good with RSD values of 13% for coumaphos and 14% for dichlorvos. The detection limits (LOD) were 0.060 microgL-1 for dichlorvos and 0.052 for coumaphos. The quantification limits (LOQ) were 0.086 microgL-1 for dichlorvos and 0.066 microgL-1 for coumaphos. The results obtained in this study suggest that SPME is a suitable technique for residual pesticide analysis of milk. The data demonstrate that particular OP pesticides used in dairy farming in the region of Minas Gerais were found to contaminate cow whole milk, and the residues are not removed by treating the milk by boiling.     

Development of an immunochromatographic assay for the rapid detection of bromoxynil in water

A rapid immunochromatographic one-step strip test was developed to specifically determine bromoxynil in surface and drinking water by competitive inhibition with the nano colloidal gold-conjugated monoclonal antibody (mAb). Bromoxynil standard samples of 0.01–10 mg L⁻¹ in water were tested by this method and the visual limit was 0.06 mg L⁻¹. The assay only required 5 min and one-step by dispensing a drop of sample solution onto a strip. Parallel analysis of water samples with bromoxynil showed comparable results from one-step strip test and ELISA. Therefore, the one-step strip test is very useful as a screening method for qualitative detection of bromoxynil in water.     

有机磷农药纳米磁珠酶联免疫分析方法研究

将有机磷农药通用抗体固化在自行制备的纳米磁珠表面,以甲醇、丙酮、pH及包被纳米磁珠的抗体稀释度为主要影响因素,依据均匀设计法和间接竞争酶联免疫反应原理,对纳米磁珠酶联免疫分析(ELISA)方法进行了优化,并开展了纳米磁珠抗体复合物对多种有机磷农药识别作用的比较研究。结果表明,无论是甲醇还是丙酮,抗体稀释度与溶剂互作对半抑制浓度(IC50)的影响最大;与传统ELISA相比,纳米磁珠间接竞争ELISA对毒死蜱、喹硫磷、敌百虫、三唑磷、乙拌磷、伏杀磷、对硫磷、敌敌畏和久效磷均有较好的识别作用,IC50为1.29～6.34μg/mL,比传统ELISA降低了68.3%～95.6%,灵敏度大大提高。