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991.
L. Gruzdiewa P. Dokurno J. Rak J. Błażejowski 《Journal of Thermal Analysis and Calorimetry》1995,45(4):849-858
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. 相似文献
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995.
Rohde M Schenk JA Heymann S Behrsing O Scharte G Kempter G Woller J Höhne WE Warsinke A Micheel B 《Applied biochemistry and biotechnology》1998,75(1):129-137
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. 相似文献
996.
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. 相似文献
997.
B. E. Richter 《Journal of separation science》1985,8(6):297-300
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. 相似文献
998.
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. 相似文献
999.
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. 相似文献
1000.
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. 相似文献