植物酶抑制技术用于检测蔬菜中有机磷及氨基甲酸酯类农药残留

应用植物酶抑制技术检测蔬菜中的有机磷及氨基甲酸酯类农药。用小柱对样品进行预处理，可去除叶绿素的干扰、提高检测灵敏度。提出了抑制率阈值（15％）。应用本方法对市售蔬菜的农药残留进行了调查，检出率约为10％。     

Study of multiresidue analytical method for organonitrogen and organophosphorus pesticides in soil and water

A gas chromatographic method without derivatization was developed for the residue analysis of 10 organonitrogen and 9 organophosphorus pesticides in soil and water. The samples were blended or shaken with acetone for extraction. The extracts were cleaned up by coagulation, then, re-extracted with three 50 ml portions of dichloromethane. The final residue was detected by gas chromatography equipped with NPD. All of the 19 pesticides were completely separated at a constant temperature. The method described above was applicable to the simultaneous determination of 10 organonitrogen and 9 organophosphorus pesticides .in soil and water with the satisfactory recovery (from 82.42% to 103.57%), coefficient of variance (from 0.17% to 12.57%) and limit of detection (from 0.0006 ppm to 0.058 ppm).     

三种有机磷农药对三角褐指藻活性氧伤害的差异性研究

３种有机磷农药－久效磷、对硫磷和辛硫磷对三角褐指藻的生长都有抑制效应，它们的７２ｈ半抑制剂量（７２ｈ·ＥＣ５０）分别为９．７４ｍｇ／Ｌ、８．２０ｍｇ／Ｌ和１．５２ｍｇ／Ｌ。结果表明，３均能引起藻细胞活性氧含量的增加，从而导致生物膜系统的膜脂过氧化和脱酯化伤害。这种由膜脂过氧化和脱酯化作用造成的膜损伤在３种农药中显示出较大的差异性。     

活性炭纤维萃取浓缩水样中微量有机磷农药

采用活性炭纤维(ACF)为固相萃取剂填料,萃取测定水样中微量有机磷农药。研究分析了ACF用量、洗脱剂类型、农药初始质量浓度、水样过柱速度及pH等因素对萃取回收率的影响。结果表明:洗脱剂类型和ACF用量是显著的影响因素。最佳萃取条件为:含0 1μg L有机磷农药的1L加标水样,需0 2gACF和8mL二氯甲烷,水样过柱速度40mL min。pH对萃取影响不大。萃取回收率为80 7%～118%。      

蔬菜中有机磷农药残留的生物传感器法检测

将乙酰胆碱酯酶(AChE)固定在醋酸纤维膜上,将该膜组装在一支pH玻璃电极敏感膜表面,制成用于测定有机磷农药的电位型生物传感器,优化其制备方法。当溶液中存在有机磷农药,酶的活性受到抑制,酶活性的降低引起pH玻璃电极电位的改变,其改变程度与溶液中农药的浓度大小有关。用本文方法测定了蔬菜中的对硫磷、辛硫磷、氧乐果、敌敌畏,结果满意。     

不同有机物料对有机磷农药污染土壤酶活性及土壤微生物量的影响

农药污染严重影响了土壤的生态和食品的安全,为了解有机物料对农药污染土壤修复的影响,本文采用室内恒温恒湿培养的方法,研究了在有机磷农药污染的土壤中加入葡萄糖、堆肥、秸秆3种不同的有机物料对土壤微生物及土壤酶活性的影响,结果表明：有机磷农药对土壤微生物生物量碳和土壤的呼吸强度都有一定的影响,具体表现为前期（0～3 d）抑制,中期（3～40 d）为促进作用,后期（40 d以后）恢复稳定。加入有机物料后,显著提高了土壤的微生物生物量碳和土壤的呼吸强度,其中葡萄糖、堆肥、秸秆处理分别在第9、30、40天时的土壤的微生物生物量碳最高,在第9、30、50天时土壤的呼吸强度最高。有机磷农药对土壤过氧化氢酶和土壤脲酶影响表现为先抑制后激活,然后恢复的变化趋势。加入不同有机物料后,堆肥和秸秆对土壤过氧化氢酶和土壤脲酶都有促进作用,显著提高了其活性。堆肥处理的土壤过氧化氢酶、脲酶活性分别在0～20 d,20 d为最高,秸秆处理的土壤过氧化氢酶、脲酶活性都在40～50 d为最高。培养结束时（70 d）,秸秆、堆肥处理的土壤过氧化氢酶、脲酶活性要高于葡萄糖、空白处理。葡萄糖处理在前期（0～40 d）对过氧化氢酶、脲酶活性有一定的影响,到后期（40～70 d）同空白之间差异不大。研究结果表明有机物料的加入可以提高土壤微生物量和土壤的呼吸强度,提高土壤酶的活性,对于农药污染土壤的修复具有积极的作用。     

Feasibility of using salivary biomarkers to assess human exposure to chlorpyrifos

The objective of this study was to determine the feasibility of using salivary biomarkers to assess chlorpyrifos exposure using data collected from laboratory controlled animal study, as well as from farmers in Thailand and Nicaragua who applied chlorpyrifos in the field. Time-matched saliva and arterial blood samples were collected from rats and adult agricultural workers, while spot saliva samples were collected from children. Specimen samples were analyzed for chlorpyrifos using a commercially available enzyme-linked immunosorbent assay. The results from both animal and farmer studies show that chlorpyrifos is excreted into saliva. Nevertheless, salivary excretion of chlorpyrifos seems to differ from other pesticides, as evidenced by the lack of correspondence of chlorpyrifos levels between saliva and plasma samples. The lower chlorpyrifos concentrations in saliva collected from rats, and from farmers and their children, may have resulted from the rapid hydrolysis of chlorpyrifos during the intracellular passive diffusion in the salivary gland. In conclusion, chlorpyrifos is excreted into saliva; however, the majority of chlorpyrifos that is excreted in saliva may have been metabolized due to base-dependent hydrolysis. Because of this finding, it was hypothesized that it would be ideal to measure its metabolite, 3,5,6-trichloropyridinol, in saliva as the biomarker for chlorpyrifos exposure.     

Photodegradation of the organophosphorus pesticides chlorpyrifos,fenamiphos and vamidothion in water

The photodegradation of the pesticides chlorpyrifos, fenamiphos and vamidothion in water containing 2–4% methanol was examined. Acetone (5%) was added as photosensitizer in the photolysis of vamidothion. A suntest apparatus equipped with a xenon arc lamp which exhibits a radiation very close to natural sunlight was employed. Analyses were performed by direct injection of the water samples containing the photoproducts into a liquid chromatograph with diode array and thermospray mass spectrometric detection. The major photodegradation products were identified by matching their diode‐array spectra with the corresponding spectra of the authentic standards, their retention times and the spectra obtained using positive and/or negative thermospray mass spectrometry. 3,5,6‐trichloro‐2‐pyridinol, fenamiphos sulfoxide and vamidothion sulfoxide were the major photodegradation products from chlorpyrifos, fenamiphos and vamidothion, respectively.     

镁碱化对土壤微生物活性和水解酶的影响

研究了镁碱度对土壤微生物生物量及其活性的影响,研究地点位于甘肃河西走廊疏勒河中游昌马洪积冲积扇缘。从10个具有不同镁碱化程度的采样点,采集土壤样品30个,测定了土样的pH、镁碱度、Mg2＋/Ca2＋、HCO3-＋CO32-、钠碱度、有机碳、全氮、微生物生物量碳、微生物熵、精氨酸氨化率、β-葡萄糖苷酶、磷酸酶、蛋白酶-casein、蛋白酶-BAA、脲酶等指标。结果表明：土壤pH和钠碱度没有明显的相关性,而和镁碱度、Mg2＋/Ca2＋、HCO3-＋CO32-显著正相关,相关系数分别为0.70、0.69和0.72。镁碱度和Mg2＋/Ca2＋显著正相关,相关系数为0.84。有机碳、全氮、微生物生物量碳、微生物熵、精氨酸氨化率的变化范围分别是6.4-18.5 g·kg-1、0.28-1.20 g·kg-1、23.1-351.9 mg·kg-1、0.37-2.52%、0.77-1.83μmol.g-1.d-1,和Mg2＋/Ca2＋之间显著负相关,相关系数分别是-0.52、-0.50、-0.59、-0.62、-0.65。β-葡萄糖苷酶、磷酸酶、蛋白酶-casein、蛋白酶-BAA、脲酶的变化范围分别是6.68-27.79μmol.g-1.h-1、7.03-25.99μmol.g-1.h-1、0.11-0.76μg.g-1.h-1、0.05-0.48μmol.g-1.h-1、0.07-0.61μmol.g-1.h-1吗,和微生物生物量碳之间显著正相关,相关系数分别是0.73、0.71、0.78、0.87、0.81,和Mg2＋/Ca2＋之间显著负相关,相关系数分别是-0.59、-0.58、-0.60、-0.56、-0.54。可见,镁碱化会造成土壤有机质含量下降、微生物生物量变小、微生物活性降低、水解酶活性低下,镁碱化是导致土地生产力低下的原因之一。     

用于有机磷农药残留检测酯酶的筛选

利用农药对酯酶活力的抑制反应,测定了不同浓度的敌敌畏对游离的不同动物肝脏酯酶的酶活性。实验采用从动物肝脏中提取的粗酶液在水解后与显色剂固兰B盐作用,用分光光度计测定其在595nm处的吸光度。结果表明,猪肝中α-乙酸萘酯酶(α-NA Esterase)的活力较高,且对较低浓度的敌敌畏也有较好的灵敏度。鸡肝和鸭肝α-乙酸萘酯酶对敌敌畏浓度变化不是很明显。