分散固相萃取气相色谱-负化学离子源质谱法测定大豆和玉米中20种农药的残留量

建立了一种大豆和玉米中20种农药残留量的分散固相萃取气相色谱-负化学离子源质谱分析方法。样品经乙腈提取并浓缩后加入N-丙基乙二胺（PSA）、石墨化碳黑和C18 3种填料进行分散固相萃取净化,气相色谱-负化学离子源质谱分时段选择离子监测技术测定与确证,外标法定量。所有农药在20～400 μg/L范围内线性均良好;方法的定量限(LOQ)均不高于2 μg/kg;在5,10和20 μg/kg 3个添加水平下所有农药的平均回收率均处于70%～130%之间,相对标准偏差(RSD)低于17%;运用该方法检测大豆和玉米样品时没有干扰现象。     

坚果中185种农药残留的气相色谱-串联质谱法测定

建立了花生仁、葵花籽、核桃仁和杏仁中185种农药多残留的气相色谱-串联质谱(GC-MS/MS)检测方法.样品经乙腈(含1%乙酸)均质提取,EN\1-18串联PSA固相萃取柱净化,在多重反应监测(MRM)模式下进行气相色谱-串联质谱法测定.185种农药在坚果样品中的检出限(S/N=5)为0.02～526.4μg/kg,定...     

基质标准校正-气相色谱-质谱法同时检测地下水中有机氯农药和多环芳烃

建立了同时检测水中17种有机氯农药和16种多环芳烃的气相色谱质谱分析方法。采用C18固相萃取技术萃取水中的有机氯农药和多环芳烃,分析了产生基质效应的主要原因,对不同基质样品进行了回收率比对试验。结果表明方法检出限(LOD)均低于2.0 ng/L,方法所评估的定量限(LOQ)均低于20.0 ng/L,回收率为70%~130%。     

溶胶-凝胶法制备C18固相微萃取头及其在有机氯农药残留检测中的应用

以十八烷基三乙氧基硅烷(C18-TEOS)、四乙氧基硅烷(TEOS)、乙醇、盐和水酸为原料,采用溶胶-凝胶法制备了十八烷基(C18)固相微萃取头,利用所制备萃取头实现了水样中11种有机氯农药的检测。在优化条件下,使用该萃取头对有机氯农药(OCPs)萃取后用气相色谱/电子捕获检测器(GC/ECD)测定,检出限为0.01～0.24μg/L,相对标准偏差为3.0%～13.3%。该方法用于鱼塘水、湖水及自来水中OCPs的检测,结果满意。所制备的萃取头在不同溶剂中浸泡后,对有机氯农药的萃取性能无明显变化。使用50次后,C18萃取头的萃取性能未变化。结果表明,所制备的C18固相微萃取头涂层均匀,具有多孔结构,稳定性高,有很好的实用价值。     

分散固相萃取-气相色谱-串联质谱法测定蔬菜中107种农药的残留量

采用分散固相萃取-气相色谱-串联质谱(QuEChERS-GC-MS/MS)建立了蔬菜中107种农药残留量的分析方法。样品由含1%冰醋酸的正己烷饱和乙腈提取、分散固相萃取法净化,采用气相色谱-串联质谱方法在分时段选择反应监测模式下进行测定,外标法定量。所有农药在0.05～1 mg/L范围内线性关系均良好;所有农药的方法定量限(LOQ)均低于10 μg/kg;在10 μg/kg的添加水平下,大蒜、青刀豆、萝卜和菠菜4种基质中绝大多数农药的平均回收率处于60%～130%之间,相对标准偏差(RSD)不大于15.3%。该方法不仅能用于多种蔬菜基质中107种农药残留的检测,而且还能较好地解决本底成分相当复杂的大蒜基质极易出现的干扰问题。     

基质固相分散-高效液相色谱法测定鲫鱼肌肉中残留的辛硫磷

建立了鲫鱼肌肉中残留的辛硫磷的基质固相分散-高效液相色谱-二极管阵列检测(MSPD-HPLC-DAD)的分析方法。通过优化样品处理条件,确定选取0.50 g鲫鱼肌肉样品与1.5 g弗罗里硅土、0.5 g无水硫酸钠混合研磨,并采用丙酮-正己烷溶液(体积比为40:60)为洗脱剂,洗脱剂用量为25 mL。优选的最佳色谱条件为：ODS色谱柱(250 mm×4.6 mm,5 μm),流动相为甲醇-水(体积比为50:50),流速0.6 mL/min,检测波长270 nm,进样量为20 μL。在上述条件下,辛硫磷质量浓度在0.01～10 mg/L范围内与响应信号呈良好的线性关系(r20.9994),检出限为3.3 μg/kg;相对标准偏差为1.1%～6.3%(n7);3个添加水平(0.05,0.1,1 mg/kg)下得到的回收率为88%～112%。该方法操作简单,耗时少,精密度高,符合农残分析的要求。     

凝胶渗透色谱净化气相色谱-质谱法检测河豚鱼、鳗鱼和对虾中191种农药残留

建立了河豚鱼、鳗鱼和对虾中191种农药多残留的气相色谱-质谱分析方法。样品用乙酸乙酯-环己烷(体积比为1:1)均质提取,凝胶渗透色谱净化,收集26～44 min的流出液并进行在线浓缩,通过气相色谱柱(DB-1701)分离后在选择离子监测(SIM)模式下进行质谱检测。分别以最低定量限和4倍最低定量限为添加浓度对河豚鱼、鳗鱼和对虾样品进行了两个水平的添加回收率实验,方法的回收率范围为50.2%～120%,其中89.5%的农药的回收率为70%～120%,相对标准偏差范围为0.6%～21.6%。方法的最小检出限和最低定量限范围分别为0.002～0.3 mg/kg和0.007～1.2 mg/kg。该方法的灵敏度、准确度和精密度均符合农药多残留检测的技术要求,适用于河豚鱼、鳗鱼和对虾等动物源性水产品中多种农药残留的检测。     

固相萃取-毛细管气相色谱法测定人参制品中19种有机氯农药的残留量

毛细管气相色谱法;有机氯农药;固相萃取;人参制品     

Determination of Organophosphorus Pesticides in Water Using C18 or Florisil Sep-Pak Cartridge and Gas Chromatography with Flame-Photometric Detection

Simple methods for the concentration and clean-up of fifteen organophosphorus pesticides in water using a C₁₈ Sep-Pak cartridge or a Florisil Sep-Pak cartridge and subsequently determining the pesticides by gas chromatography with flame photometric detection have been developed. The conditions for stepwise or simultaneous desorption of these pesticides from the Sep-Pak cartridges are given.     

Biodegradation and bioaccumulation of fenitrothion in rat liver

The biodegradation of fenitrothion O,O-dimethyl-O-(3-methyl-4-nitro phenyl) phosphorothioate was investigated in rat liver after administration of various doses (5 mg/100 g body weight and 20 mg/100 g body weight) in acute treatment and 1 mg/100 g body weight in chronic treatment. High performance liquid chromatography of the pesticide and its metabolites formed in liver in acute treatment showed time-dependent sequential conversion of pesticide into three major metabolites within 24 h. These metabolites were separated and purified to homogenity by HPLC and characterized by IR spectroscopy as O,O-dimethyl-O-(3-methyl-4-amino phenyl) phsophorothioate (metabolite 1), O,O-dimethyl phosphorothioate (metabolite II) and O,O-dimethyl phosphate (metabolite III) in the fi rst dose (5 mg/100 g body weight). Metabolite II was found to be different in the second dose (20 mg/100 g body weight) and identified as O,O-dimethyl O-3-methyl-4-amino phenyl phosphate. The results with the fi rst dose indicated reduction of the nitro group in fenitrothion as step I followed by hydrolytic clevage of the P-O-aryl bond in metabolite I and oxidative desulphurylation of metabolite II. At higher dose (20 mg/100 g body weight) oxidative desulphurylation takes place as step II followed by hydrolysis of metabolite II. The bioaccumulation of fenitrothion within 60 days during chronic treatment showed no metabolite but continuous reduction in fenitrothion concentration, indicating excretion of pesticide and its products in urine and in faeces.