Application Of Gel Permeation Chromatography In Pesticide Residue Analysis

Gel permeation chromatography (GPC) is one of the useful sample cleanup methods in pesticide residue analysis because of its automation and convenience. In the past, the use of this method is only experiential as well as time and solvent consuming.In this paper, For the first time, the influence of different chromatographic conditions which affect the cleanup efficiency were researched, including speed of mobile phase, the amount of loaded sample (corn oil ), etc, in different conditions in solvent A,B and C ,we found that solvent A and B are better than C in cleaning up oil, the amount of sample loading on the column is the main factor which affected the oil cleanup efficiency. We also researched the factors such as the molecular weight and size, the element component of the compound which influence the retention time (retention volume) of pesticide molecule in solvent A and C, based on the research, we found three regularities which affected molecular retention volume, the first one is the more polarity of solvent, the smaller size of the GPC holes and the later of the molecular retention time; the second one is if there are rings or polarity atoms in molecular, the molecular size is smaller than others which has the same molecular weight ;the third one is the polarity atoms or phenyl in the compound may occur the interaction of the compound and GPC, then the molecular will elute from the column lately . We also compared three GPC analytical columns in the clean-up efficiency and operation conditions.Based on the experience of using GPC and the research of the commercial machines, we designed and developed a new GPC auto-machine and a small GPC clean-up column, measured the main technical parameters. Based on the results of theoretical research, we mainly used GPC for sample clean-up and analysed multi-residue pesticide .We also researched the on-line GPC-SPE clean-up method to clean up some completed sample. From the results, we can see that GPC is a very effective method and using this auto-machine to clean up sample can save a lot of time and solvent, and meet all requirement of preparation for pesticide residue analysis sample.