Thermal behaviour of organochlorine pesticides in the presence of alkaline substances

Selected organochlorine pesticides, namely lindane, PCNB,p,p′-DDT andp,p′-methoxychlor, and some related compounds (p,p′-DDE andp,p′-DMDE) were heated in the presence of powdered KOH, Na₂CO₃, CaO and CaCO₃ in order to check whether degradation of the compounds is feasible in moderate conditions and temperatures. Thermal analyses, as well as investigations concerning the search for the reaction products revealed that processes occurring at atmospheric pressure are either simple volatilization of organic molecules, observed upon heating of mixtures containing lindane, PCNB,p,p′-DDE andp,p′-DMDE, or volatilization accompanied with decomposition towards HCl andp,p′-DDE andp,p′-DMDE, noted when heating mixtures ofp,p′-DDT andp,p′-methoxychlor with alkaline substances, respectively. Complementary theoretical calculations enabled insight into the mechanism of HCl elimination fromp,p′-DDT andp,p′-methoxychlor.     

不同柱前压控制方式对毛细管气相色谱法分离测定多种有机磷农药的效果比较

不同柱前压控制方式对毛细管气相色谱法分离测定多种有机磷农药的效果比较周昱，刘胜利，庄无忌（厦门进出口商品检验局厦门３６１０１２）（中国商检技术研究所北京１０００２５）１前言１９９２年美国惠普（ＨＰ）公司推出了带有电子压力控制（ＥＰＣ）功能的毛细管分流...     

有机溶剂对某些有机磷农药的MECC洗提影响的研究

以有机磷农药甲基对硫磷、对硫磷等为被试验物质，探讨了在十二烷基硫酸钠、硼砂电解液中加入甲醇、乙醇、异丙醇、乙腈等有机溶剂对某些有机磷农药的毛细管胶束电动色谱分离的影响。并从电解液的物理化学性质和毛细管色谱动力学两方面阐明了其影响机理     

HPLC检测煤、石油产品中的极性化合物

本文以高效液相色谱(HPLC)分析为主要手段,对煤、石油加工产品中的含氧、含氮的极性物进行了检测。试样中极性物的富集,采用经典柱液体色谱法、组分的分离,采用双ODS柱、以色谱保留值和质谱核实作定性测定。文中,以石脑油裂解产品及煤超临界抽提产品为对象,列举了它们的某些含氧、氮的极性物的定性、定量检测结果及典型色谱分离谱图。     

Production and characterization of monoclonal antibodies against urea derivatives

A panel of monoclonal antibodies was generated against the ureabased haptenN-(2-N-chloroacetylaminobenzyl)-N′-4-chlorophenylurea as a tool for building up sensitive immune assays to detect urea derivatives and to screen them for catalytic antibodies (Abs). Eleven hybridomas were obtained that produced Abs reactive to the hapten. All Abs were of IgG class. Crossreactivities of the Abs to different haptens were examined, especially to a possible transition-state analog. Only four of the hybridomas (R2-DA10/F7, R2-GE7/H2, R2-HC2/A5, R2-HD6/F7) produced Abs crossreactive with the transition-state analog. From the 11 hybridomas, hybridoma B76-BF5 was chosen for further characterization. Compared to the other Abs, B76-BF5 showed the strongest binding and had a rather restricted specificity. These Abs could be used to build up a sensitive enzyme immunoassay for the detection of the hapten. All Abs were screened for crossreactivity with the pesticides monuron and diuron. No reactivity could be detected. In addition, the nucleotide sequences of the variable light and heavy chain genes of the similarly reactive Abs B76-BF5, B76-BB3, R2-DA10/F7, and R2-GA6/G3 were determined to clarify whether structure and binding specificity of these Abs showed any correlation.     

Optimization by orthogonal array design of solid phase extraction of organochlorine pesticides from water

Summary A two-level orthogonal array design (OAD) to optimize the solid phase extraction of organochlorine pesticides is described. Parameters including eluting solvents, SPE cartridges packed with C₁₈-bonded silica from different manufacturers, duration of air drying, pH, salinity and humic acid have been examined using OAD. This systematic approach was then used to optimize the relevant parameters required for off-line solid phase extraction of organochlorine pesticides from water. The optimized parameters were employed to perform extraction of the pesticides from natural waters.     

Modified flame ionization detector for the analysis of large molecular weight polar compounds by capillary supercritical fluid chromatography

The modifications made to a flame ionization detector (FID) to facilitate the detection of large molecular weight polar compounds analyzed by capillary supercritical fluid chromatography are described. Some specific examples are given to demonstrate that polar compounds can be effectively eluted using deactivated fused silica capillary columns and supercritical carbon dioxide at 40°C.     

A study of solid surface polarity using inverse gas chromatographic retention data

Summary Sensitivities of a solid surface to dispersive and nondispersive (polar) interactions can be readily estimated by a multiple regression analysis of inverse gas chromatographic retention data of a set of probe solutes. This analysis is based on linear free energy relationships (LFERs). The sensitivity to the latter type of interactions can be used as a measure of the surface polarity of the solid. This has been shown in the case of a graphitized carbon fiber and the method is also applicable to other solids.     

High resolution GC of unsaponifiable matter and sterol fraction in vegetable oils

Summary The analysis of both the total unsaponifiable matter and the sterol fractions in vegetable oils has been performed with a new polar column (TAP, Chrompack). The use of a polar column, which is characterized by high thermal stability, has led to the identification of a greater number of constituents than the use of a nonpolar column (i.e. SE 52, SE 54). The polar column enhances the separation of the main classes of unsaponifiable matter (sterols, 4-methyl sterols and 4,4-dimethyl sterols). When used for the unsaponifiable and sterol fraction analyses, it offers a powerful tool for characterizing the lipid source.     

GC-NPD investigation of the recovery of organonitrogen and organophosphorus pesticides from apple samples: The effect of the extraction solvent

Summary A gas chromatographic method employing a capillary column and a selective nitrogen/phosphorus detector (NPD) has been developed for the determination of organophosphorus (OP) and organonitrogen (NP) pesticides in horticultural samples (apples). The separation of sixteen pesticides and the internal standard was performed in thirteen minutes. The analytical characteristics of the method, including linear response ranges, detection limits, and reproducibility, have been studied using a 11 mixture of ethyl acetate and xylene as extraction solvent. The possibility of mutual interference between pesticides has also been studied. A procedure for the quantitative extraction of the sixteen pesticides from apple samples has also been developed; for fifteen of the pesticides recoveries >85% were obtained after 90 minutes extraction. The effect of different solvents both on recovery and on the sensitivity of the subsequent chromatography were also investigated. It was found that the sensitivity required must be considered when the solvent for sample treatment is selected.