| Pesticides, as one of the major pollutant sources of environment and food, now are becoming more concerned by publics and many countries in the world with the increases of varieties and usage of pesticides. In recent years, new analytical methods, especially multiresidues analysis methods, have been developed greatly. In this paper, through the dynamic study of the pesticide multiresidues in muskmelon, the methods are presented for their simultaneous determination by high-performance liquid chromatograph (HPLC) and liquid chromatography-mass spectrometry (LC-MS). These methods are available to be applied to the dynamic analysis of the pesticides involved in muskmelon during storage and transportation and also to the pesticide residues in vegetable and fruit in regulatory production and daily life. This paper consists of five chapters.1. A review concerning the analytical methods of the pesticide residues is presented. The regulatory and recent developed technologies of the extraction and instrumental analysis are discussed. The significance of the research in this paper is also given.2. The procedures purifying pesticide products for analysis standards , i.e., thiabendazole(TBZ), thiophanate methyl(TFM), iprodione(ID), carbendazim(MBC), imazalil(IMZ), are reported. These methods are presented according to the variety of the market pesticide products and the properties of the pesticides mentioned above. The purities of thereferences extracted are verified by melting points, molecular mass and elementary analysis.3. A HPLC method for the simultaneous determination of the amounts of IMZ and TBZ in muskmelons is investigated. The samples were extracted with ethyl acetate followed by a simple clean-up procedure to separate the analytes from the coextractives. Liquid chromatographic separation was performed on an InertsilC8-3 column with acetonitrile-water (75:25) as mobile phase. The method was quantified by an external standard mode. The detection limits of the method were 1 ng for TBZ and 2 ng for IMZ, and the coefficients of variation, recoveries were 1.5-4.2%, 87.5-98.0%, respectively. The method has been applied to the quantitative determination of IMZ and TBZ in muskmelons with satisfactory results. The method is simple, rapid, and accurate.4. A HPLC method is investigated for simultaneous determination of carbendazim (MBC), thiabendazole (TBZ) and thiophanate-methyl (TFM) in muskmelons. Analyses were performed with simply clean-up procedure followed by HPLC-DAD(diode array detector) detection on a reversed-phase column eluted with acetonitrile- 8 mM phosphate buffer (35:65, v/v). The recoveries of MBC, TBZ and TFM from muskmelon samples were in the range of 80.9-86.4%, 90.8-96.0% and 92.5-97.3% respectively with coefficients of variation ranging from 0.8% to 3.2%. The method was applied to determining MBC, TBZ and TFM in the muskmelons during storage, and the results were satisfied.5. A HPLC-MS method is presented for the simultaneous determination of the micro amounts of TBZ, TFM, ID in muskmelon samples by HPLC-MS. The method involved a simple and rapid extraction procedure and liquid chromatography coupled to electrospray mass selective detection. lonization was performed at atmospheric pressure in an electrospray-type source (+) and quantitative detection was carried out using the selected ion monitoring (SIM) mode. Limits of detection were 0.1 pg for TBZ, 10 pg for TFM, 3 ng for ID. The average recoveries and relative standard deviations ranged from 81.0-110% and from 1.5-16.8%, respectively. The method was applied to the determination of TBZ, TFM and ID in melon samples with satisfactory results.
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