毛细管气相色谱同时测定水产品中多种农药残留量

建立了固相萃取-气相色谱法快速检测水产品中11种农药残留的分析方法。样品用乙腈水溶液均质提取,经盐析作用分离出乙腈层,经C18和PSA串联柱净化后用GC-FPD检测分析,采用外标法定量。方法的检出限(S/N=3)为0.004～0.008mg/kg,在加标水平为0.01mg/kg时,方法回收率为71.2%～107%,相对标准偏差为3.9%～9.5%;在加标水平为0.02mg/kg时,方法回收率为73.5%～108%,相对标准偏差为3.5%～10%。     

有机磷中毒患者的临床护理观察与分析

目的:对有机磷中毒患者进行护理观察.方法:选取30例有机磷中毒患者,并对其实施相关护理措施且进行观察与数据统计和分析.结果:实施及时和系统的临床护理后患者总有效率为96.67%且患者生命体征均得以改善(p<0.05).结论:及时和系统的护理对降低死亡率和改善患者生活质量具有十分重要的意义.     

Cerium dioxide as a new reactive sorbent for fast degradation of parathion methyl and some other organophosphates

Cerium dioxide was used for the first time as reactive sorbent for the degradation of the organophosphate pesticides parathion methyl,chlorpyrifos,dichlofenthion,fenchlorphos,and prothiofos,as well as of some chemical warfare agents—nerve gases soman and O-ethyl S-[2-(diisopropylamino) ethyl] methylphosphonothioate(VX).CeO2 specimens were prepared by calcination of basic cerous carbonate obtained by precipitation from an aqueous solution.The CeO2 samples containing certain amounts(1 wt.%–5 wt.%) of the neighboring lanthanides(La,Pr,Nd) were prepared in a similar way from pure lanthanide salts.It was shown that ceria accelerated markedly the decomposition of parathion methyl causing the cleavage of the P-O-aryl bond in the pesticide molecule.A similar reaction mechanism was proposed for the degradation of other organophosphate pesticides and nerve agents.The degradation times(reaction half-times) were in an order of minutes in the presence of CeO2,compared to hours or days under common environmental conditions.The reaction in suitable organic solvents allowed conversions of about 90% for parathion methyl loading of 20 mg pesticide/g CeO2 within 2 h with a reactant half-life in the order of 0.1 min.The key parameter governing the degradation efficiency of CeO2 was the temperature during calcination.At optimum calcination temperature(about 773.15 K),the produced ceria retained a sufficiently high surface area,and attained an optimum degree of crystallinity(related to a number of crystal defects,and thus potential reactive sites).The presence of other lanthanides somewhat decreased the reaction rate,but this effect was not detrimental and permitted the possible use of chemically impure ceria as a reactive sorbent.A fast organophosphate degradation was demonstrated not only in non-polar solvents(such as heptane),but also in polar aprotic solvents(acetonitrile,acetone) that are miscible with water.This opens new possibilities for designing more versatile decontamination strategies.The cleavage of phosphate ester bonds is of a great importance not only for the degradation of dangerous chemicals(chemical weapons,pesticides),but also for interactions of ceria(especially the nano-sized one) in biologically relevant systems.     

有机磷杀虫剂对马铃薯腐烂茎线虫趋化性的影响

[目的]研究有机磷杀虫剂对马铃薯腐烂茎线虫趋化性的影响.[方法]将马铃薯腐烂茎线虫浸渍在三唑磷、辛硫磷、毒死蜱、丙溴磷以及对照药剂阿维菌素不同质量浓度的药液中,24 h后用灭菌水清洗3次后加入1％水琼脂平板中央,36 h后观察记录线虫对灰葡萄孢菌、半裸镰刀菌、甘薯切片和马铃薯切片等不同引诱物的趋化性.[结果]质量浓度0.01～10 mg/L,线虫经三唑磷、辛硫磷和毒死蜱药液浸渍处理后仍表现出对灰葡萄孢菌的明显趋性,且由于药剂的毒物兴奋效应(Hormesis),引诱物上能诱集到更多的线虫.结果还表明:线虫经10 mg/L丙溴磷处理后,其各引诱物的引诱率明显高于对照,且对灰葡萄孢菌、甘薯和马铃薯的趋性在0.05水平上无显著性差异.[结论]三唑磷、辛硫磷、毒死蜱及对照药剂阿维菌素在低质量浓度下对马铃薯腐烂茎线虫的趋化性无影响,10 mg/L丙溴磷处理线虫后,其趋化性发生改变.     

气相色谱法测定蔬菜中9种有机磷农药残留

建立毛细管柱气相色谱法测定蔬菜中9种有机磷农药残留的分析方法。蔬菜经均质,用乙腈提取,CARB/NH2柱净化,丙酮溶解定容,采用DB–1701毛细管柱和火焰光度检测器测定,一次进行9种有机磷农药残留检测。样品加标回收率在80.2%～102.2%之间,相对标准偏差在2.15%～5.32%之间,检出限在0.004 2～0.027 mg/kg之间。实验结果表明,该方法简便、快速、灵敏、准确,各项技术指标满足蔬菜中9种有机磷农药残留检测要求。     

环保型阻燃剂的现状及发展趋势

环保型阻燃剂主要是指不含有卤素的阻燃剂,主要包括无机阻燃剂、有机硅系阻燃剂、有机磷系阻燃剂、氮系阻燃剂、纳米级阻燃剂、膨胀型阻燃剂等。文章主要分析了环保型阻燃剂的应用、发展现状及今后此类阻燃剂的发展趋势。     

胞外聚合物和腐殖质对毒死蜱于摇蚊属生物利用率的影响

以4类有机物考察毒死蜱对摇蚊幼虫生物利用率的影响:(1)购买的胞外聚合物(EPS),(2)由沉积微生物制取的EPS,(3)购买的腐殖质,(4)从北方湖泊里提取的腐殖质.每种有机物以3种浓度,采用14C同位素示踪法确定摇蚊幼虫对毒死蜱的摄取量.幼虫对毒死蜱的常规摄取量随EPS和腐殖质的增加而减少.而EPS对幼虫摄取毒死蜱...     

有机磷农药降解酶基因Oph2的克隆及甲基对硫磷降解效果研究

摘要：目的 挖掘可高效表达农残降解酶的基因,并构建含有该表达基因的工程菌,以此提供一种高效去除有机磷农残的新方法。方法 利用基因克隆获得高效表达农残降解酶基因Oph2,采用基因工程手段将其转化至毕赤酵母表达系统,对毕赤酵母的发酵产物进行SDS-PAGE定性研究和酶活定量研究,最后通过与目标底物甲基对硫磷反应,分析工程菌表达降解酶对有机磷农残的去除效果。结果 本研究成功克隆得到了高效表达有机磷降解酶基因Oph2,基因全长1000bp,编码256个氨基酸,酶蛋白分子量为37KD,并利用表达载体pPIC9K成功将其转化至毕赤酵母GS115。构建的工程菌GS115-pPIC9K-Oph2表达有机磷降解酶活性为11.57 U/mL,对6.8 mg/L的甲基对硫磷降解效率为90%以上。结论 本研究得到的工程菌GS115-pPIC9K-Oph2可高效表达有机磷降解酶,该酶活性高,对有机磷农残降解能力强,可有效应用于有机磷农残的降解。     

鲫鱼脑乙酰胆碱酯酶（ACHE）的活性测定及对有机磷农药的敏感性研究

提取不同生长期的鲫鱼脑中乙酰胆碱酶（acetylcholinesterase，AChE）并做比较，以Ellman法测定其酶活。并用正交试验方法确定了最佳测定条件。采用体外实验法研究了在最佳条件下鲫鱼脑AChE对三种有机磷农药的敏感性。研究结果表明，以体长12cm左右的鲫鱼体内AChE活性最高，正交试验得出AChE最佳测定条件组合为：酶的剂量为40μl、底物最终浓度为120mmol／L、pH值7．5、温度35℃；时间15min。鲫鱼脑AChE对农药的敏感性为敌敌畏〉辛硫磷〉乐果。     

鲫鱼乙酰胆碱酯酶性质及对有机磷农药的敏感性研究

以鲫鱼为原料,分别提取鱼脑、肌肉和肝脏乙酰胆碱酯酶(acetylcholinesterase,ACh E),研究其酶学性质及对有机磷农药的敏感性。结果表明,鲫鱼脑ACh E最适反应温度为30℃,最适p H为8.0,米氏常数(Michaelis constant,Km)为0.548 mmol/L;鲫鱼肌肉ACh E最适反应温度为35℃,最适p H为7.5,Km为1.75 mmol/L;鲫鱼肝脏ACh E最适反应温度为30℃,最适p H为8.0,Km为0.406 mmol/L。敌敌畏对鱼脑、肌肉和肝脏ACh E的半数抑制质量浓度(50%inhibition concentration,IC50)分别为1.70,3.55和4.52μg/m L,双分子速率常数(bimolecular rate constant,Ki)分别为7.40、7.21、5.94 L/mg·min;辛硫磷对鱼脑、肌肉和肝脏ACh E的IC50分别为2.45,4.05和9.46μg/m L,Ki分别为10.54,10.11和8.32 L/mg·min;毒死蜱对鱼脑、肌肉和肝脏ACh E的IC50分别为10.89、14.33和17.00μg/m L,Ki分别为7.81,6.85和4.99 L/mg·min。鲫鱼脑ACh E对常用有机磷农药表现出了较强的敏感性,可作为环境中有机磷农药残留监测的指示酶。