Residues In Vegetables And Environmental Behavior In The Soil-vegetable System Of SAs

A simple and efficient residue analytical method was examined for the analysis ofSDZ, SM2and SMZ in vegetables in this dissertation, the sensitivity and precision of themethod was investigated. The investigation of3SAs residues in vegetables was carried out.The environmental behavior of three SAs in the soil vegetable system was studied, and theeffects of combined pollution of drugs, pH of irrigation water, soil moisture content,illumination condition, etc. were also studied. The degradations of SM2in greengroceryand soil were studied too. This article has practical signification to transference of SAs insoil vegetable system and production safety of vegetables. The main results weresummarized as following:(1) A high performance liquid chromatographic method with fluorimetric detectorwas examined for the simultaneous determination of three sulfonamides in vegetablesamples. The limit of detection was1.02~1.29g/g and the limit of quantification was3.4~4.3ng/g (fresh weight) for three sulfonamides in vegetable. The average recoverieswere higher than87%, RSD was lower than10%for all samples spiked with0.2~1.0ng/gof sulfonamides. The average recoveries were higher than74.1%, RSD was lower than10.62%for all samples of different species vegetables spiked with0.1ng/g ofsulfonamides. The results showed that the method accords with demands of residueanalysis of SAs in vegetables.(2) The three sulfonamides were detected in vegetables in different levels, but thecontamination levels varied significantly with different sulfonamides. SM2was detected in97.3%of the samples, the maximum concentration was0.5824mg/kg; SMZ was detectedin24.5%of the samples, the maximum concentration was0.0296mg/kg; SDZ wasdetected in22.8%of the samples, the maximum concentration was0.0298mg/kg. Thecontents of sulfonamides varied significantly in different kinds of vegetables, thecontamination of sulfonamides in leaf vegetables and root vegetables was severe; SM2wasmainly distributed in leave and root of vegetable. The detectable rate of SDZ and SMZ invegetables sold in winter was higher than in summer. The contents of sulfonamides variedsignificantly in different vegetable produce bases, the residues of SM2in vegetables ofvegetable produce base B were severe than other vegetable produce bases. The evaluationresult showed that the contamination of SM2was the most serious, the over standard ratewas96.3%; the contamination level of SDZ and SMZ was relatively low, the over standardrates were1.8%and24.5%, respectively. The results showed that the residues contamination of sulfonamides in vegetables were serious.(3) The residues of SAs in greengrocery and soil were affected by category of drugs, combined pollution of drugs, pH of irrigation water, soil moisture content, and illumination condition. When the soil was polluted by singular sulfa-antibiotic, the residue of SM2in greengrocery was severe than SDZ (ND) and SMZ. The residues of SAs in soil and greengrocery were severe when the soil was polluted by combined pollution of drugs. The residues of SM2in greengrocery and soil were higher when the pH of irrigation water was8; the residues of SM2in greengrocery were lower when the pH of irrigation water was7. The degradation rate of SM2in soil could be accelerated by raise the soil moisture content. The degradation rate of SM2in soil could be accelerated by illumination. The dissipation equation of SM2in soil was Ct=0.3151.e-0.1063t, the half life period was4.52d; the dissipation equation of SM2in greengrocery wasCt=1.4435·e-0.1533t,the half life period was6.51d.