加速溶剂萃取-凝胶渗透色谱净化-气相色谱快速分析动物源性食品中残留的多种有机磷农药

建立了动物源性食品猪肉、牛肉、鸡肉及鱼肉中36种有机磷农药残留的快速分析方法。以乙腈作为溶剂,对试样采用加速溶剂萃取仪萃取,自动凝胶渗透色谱仪净化预处理,N-丙基乙二胺(PSA)填料再净化,毛细管气相色谱法分离,火焰光度检测器(磷型)检测,内标法定量。该方法分离效果良好,重现性好,灵敏度、精密度高,杂质干扰少。36种有机磷农药的检测限(LOD)为0.0012 mg/kg(乙拌磷)～0.014 mg/kg(吡唑硫磷),定量限(LOQ)为0.004 mg/kg(乙拌磷)～0.047 mg/kg(吡唑硫磷)。当试样中有机磷农药的添加浓度分别为0.05,0.1,0.2 mg/kg时,回收率为58.2%～106.3%。方法的最低检测限和添加回收率均符合农药残留分析的要求。     

用毛细管色谱柱分离有机磷农药

本文介绍了用SE-30毛细管柱、高速率程序升温分离13种有机磷农药。其分离效果较好,分析速度较快,有良好的线性关系和重复性。     

STUDIES ON ORGANOPHOSPHORUS COMPOUNDS XXXV——SUBSTITUENT EFFECT OF ORGANOPHOSPHORUS COMPOUNDS ON ~(31)P NMR SPECTROSCOPY

The linear relationship between the chemical shift of the resenant nucleus and the localvan der Waals steric energy calculated by molecular mechanics with MM2 force field wasextended to various organophosphorus compounds including alkyl-phosphates, -phosphonates,-phosphinates as well as -phosphine oxides. The conformational equilibria of a series of alkylO,O-1,3--propylene-and O, O-1,4-butylenephosphonates were studied by the molecular mechanicscalculations and the dynamic ~(31)P NMR spectroscopic method. As shown by these experimentaldata, the former existed in a chair form, and the latter in a twist boat form with an equatorialalkyl group in both configurations, either in gaseous state or in non-polar solvent.     

Electrochemical activity of rhodium complexes supported on fibrous-carbon material

The redox properties of heterogenized Rh^I, Rh^II, and Rh^III complexes with different, particularly organophosphorus, ligands were studied by cyclic voltammetry (CVA). The support is a carbon-paste electrode based on a fibrous-carbon material and activated carbon. The electrochemical reduction of Rh^III produces Rh metal, which further catalyzes hydrogen evolution. After the reduction of water-soluble binuclear Rh^II complexes, the CVA curves exhibit peaks of electrocatalytic hydrogen evolution and irreversible Rh^I→Rh^II oxidation. The Rh^II complexes with organophosphorus ligands are characterized only by the peak of Rh^I→Rh^II oxidation. After reduction, the Rh^I complexes behave as a pseudo-reverse Rh⁰/Rh^I pair. The electron-donating properties of the ligand determine the reversibility of the system. The degree of structurization of the carbon matrix and the presence of phosphorus(v) atoms in it affect the electrochemical activity of the Rh^II and Rh^I complexes. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 5, pp. 908–914, May, 1999.     

液液微萃取-甲基衍生化/气相色谱法对水中氯代酸除草剂的测定

在pH大于12的条件下使水样中的氯代除草剂全部水解为盐,用正己烷和甲基叔丁基醚混合溶剂提取有机杂质,再在酸性条件下经5 mL甲基叔丁基醚提取,重氮甲烷甲基衍生化30 min后用带微电子捕获检测器的毛细管气相色谱分析,以4,4-二溴八氟联苯为内标物进行定量.茅草枯、麦草威、2,4-D、五氯苯酚的质量浓度分别在5.0 ～500、1.0 ～200、5.0 ～500、0.5 ～100 μg/L范围内与色谱峰面积呈良好的线性关系(r= 0.994 5 ～0.998 0),检出限分别为1.0、0.5、1.0、0.1 μg/L.用该法测定南京玄武湖水样中的茅草枯,其质量浓度为7.1 μg/L,4种被测组分在高、中和低添加水平下的回收率分别为102% ～105%、96% ～110%、87% ～109%.同时建立了一种生产重氮甲烷的新原料--N-亚硝基-N-甲基脲的简易方法.     

分子印迹固相萃取-液相色谱质谱联用对4种磺酰脲类除草剂残留的测定

采用苄嘧磺隆分子印迹固相萃取柱(MISPE)对加标大米中的苄嘧磺隆、甲磺隆、苯磺隆和烟嘧磺隆4种磺酰脲类除草剂进行净化和富集预处理,并采用LC-MS方法进行定量分析.质谱条件为:正离子检测模式(M+H),检测质量范围为m/z 200 ～800 ,毛细管电压3.93 kV,锥孔电压20 V,脱溶剂温度250 ℃,辅助气流速4 L/min.4种磺酰脲类除草剂在0.01 ～0.70 mg·L~(-1)范围内线性良好.回收率为68% ～100%,表明样品液中的烟嘧磺隆、甲磺隆、苯磺隆和苄嘧磺隆能直接被分子印迹固相萃取柱中的印迹位点保留,而杂质几乎不被保留.分子印迹固相萃取柱对磺酰脲类除草剂表现出良好的识别性能.     

基质效应对有机磷农药测定的影响及其解决方法

该文以液液萃取-气相色谱法探讨了基质对乐果、甲基对硫磷、马拉硫磷和对硫磷4种有机磷测定的影响以及解决方法.研究表明,气相色谱法测定有机磷农药的过程中基质效应显著存在,其基质增强比例为1.01 ～3.46.基质效应由基质种类及含量、有机磷农药种类及浓度等因素决定,同时与萃取溶剂、测定条件(如衬管、进样口温度等)有关.不同萃取溶剂对有机磷农药的萃取效率不同,但均存在基质增强效应;当进样口温度为260 ℃时,可最大程度降低基质在衬管中的残留,且不造成有机磷农药的分解;衬管则应首选带玻璃棉的.实际样品/标准样品的交替进样方式可以降低基质效应强度,但难以达到回收率要求,而校正因子校正法及分析保护剂法则是降低或消除基质效应的可行办法.     

多壁碳纳米管-固相萃取分析有机磷农药残留

建立了多壁碳纳米管为吸附剂的固相萃取净化和火焰光度检测气相色谱法测定蔬菜中16种有机磷农药的方法.采用双柱双检测器进行定性和定量分析.建立了水相和有机相上样两种净化体系.水相上样时采用pH 5.0醋酸-醋酸钠缓冲体系,真空抽干除水,二氯甲烷为洗脱剂,只有9种农药的回收率>75%.对于正己烷溶解药物,丙酮-正己烷(5: 5,V/V)作洗脱剂的有机相净化体系,16种农药回收率均>75%.本研究提出的有机相上样净化体系用于黄瓜、卷心菜、韭菜、生姜和洋葱等样品的净化,效果良好,表明多壁碳纳米管具有较强的吸附和去除色素的能力,可以克服色素对测定的干扰.     

高效液相色谱-电喷雾串联质谱法快速测定纺织品中苯氧羧酸类除草剂残留量

建立了纺织品中7种苯氧羧酸类除草剂的高效液相色谱-电喷雾串联质谱(LC-ESI-MS/MS)快速检测方法.样品经甲酸酸化的丙酮溶液超声提取两次,无需其它净化过程.液相色谱使用C18反相色谱柱,流动相为醋酸铵水溶液和甲醇,在梯度条件下分析.在选择反应检测(SRM)负离子模式下进行质谱信号采集,采用两对同位素离子对进行定性和定量分析.选取3种有代表性的纺织品进行方法检出限(LOD)、定量限(LOQ)、线性、回收率和精密度的验证.方法的LOQ为 0.9～2.4 μg/kg; 回收率为85%～106%; 相对标准偏差为2%～11%.本方法简便、有效、可靠、灵敏,能够满足国际生态纺织品标准(Oeko-Tex Standard 100)的限量要求,适用于纺织品中苯氧羧酸类除草剂的日常检测及确证.     

Dispersive liquid–liquid–liquid microextraction combined with liquid chromatography for the determination of chlorophenoxy acid herbicides in aqueous samples

A novel sample preparation method “Dispersive liquid–liquid–liquid microextraction” (DLLLME) was developed in this study. DLLLME was combined with liquid chromatography system to determine chlorophenoxy acid herbicide in aqueous samples. DLLLME is a rapid and environmentally friendly sample pretreatment method. In this study, 25 μL of 1,1,2,2-tetrachloroethane was added to the sample solution and the targeted analytes were extracted from the donor phase by manually shaking for 90 s. The organic phase was separated from the donor phase by centrifugation and was transferred into an insert. Acceptor phase was added to this insert. The analytes were then back-extracted into the acceptor phase by mixing the organic and acceptor phases by pumping those two solutions with a syringe plunger. After centrifugation, the organic phase was settled and removed with a microsyringe. The acceptor phase was injected into the UPLC system by auto sampler. Fine droplets were formed by shaking and pumping with the syringe plunger in DLLLME. The large interfacial area provided good extraction efficiency and shortened the extraction time needed. Conventional LLLME requires an extraction time of 40–60 min; an extraction time of approximately 2 min is sufficient with DLLLME. The DLLLME technique shows good linearity (r² ≥ 0.999), good repeatability (RSD: 4.0–12.2% for tap water; 5.7–8.5% for river water) and high sensitivity (LODs: 0.10–0.60 μg/L for tap water; 0.11–0.95 μg/L for river water).