The Residue Determination And Biomarkers Study Of Profenofos In Rapes

ObjectiveProfenofos is a new organophosphorus broadspectrum pesticide and can kill insects by inhibiting the activities of acetylcholinesterase especially. The pollution of profenofos in vegetables is inevitable because the amount of profenofos use increases day after day. Few profenofos residue will not create immediate and direct poisoning to the human body, but it can cause cancer sterility and internal secretion turbulence if we eat these polluted vegetables for a long time because the molecular structure of profenofos is quite stable. If people massively eat these polluted vegetables, their central nervous system could be destroyed and they died of convulsion. At the present time the authority usually judge the degree of vegetable pollution by detecting the residue of pesticide ,but these examination methods are not simple fast and highly effective enough. This research intends to establish one kind examination technology of profenofos residue which is simple . fast and highly effective on one hand. On the other hand this research intends to find one kind or several kinds of quite sensitive biomarkers which can use as early diagnosis guideline in profenofos polluted vegetables.Methods1. Field experimentField experiment is taken to spray high-dose and low-dose profenofos cream in rape field. The profenofos cream was sprayed every other day and 3 times altogether. The rape samples were gathered in 0d, 1d 3d 5d 7d 9d 11d after the last time profenofos cream was sprayed. The profenofos residue the activities of antioxidant enzyme(peroxidase catalase superoxide dismutase) the content of antioxidant molecule(glutathione vitamin C) and the content of malondialdehyde were detected separately.2. The determination of profenofos residue Rape samples were withdrawn by acetone/ n-hexane purified by active carbon concentrated by rotary evaporator and detected by gas chromatography-flame photometric detector (GC-FPD).3.The detection of biomakerThe activities of peroxidase(POD) catalase(CAT) and superoxide dismutase(SOD), the content of glutathione vitamin C and malondialdehyde were measured by ABTS method ultraviolet spectrophotometry NBT assay Ellman method titration method and thiobarbituric(TBA) assay separately.Results1. The dynamic degradation of the profenofos residuesThe recovery rate of Profenofos in rapes is 96.3%-104.7% and the accuracy is 3.6%⁴.8%. This method is simple, rapid,, accurate and precise. The dynamic degradation of the profenofos residues in rapes was studied. The result showed a rapid degradation rate of the profenofos residues in rapes, and its degrading pattern is consistent with one range reaction of dynamics. The half-value period of profenofos residues in low-dose group is 1.59 days and it's degeneration equation is y= 127.15e^-0.4348x. The half-value period of profenofos residues in high-dose group is 1.66 days and it's degeneration equation is y= 1332.4e^-0.4164x.2. Effect of Profenofos on POD Activity in rapesThe activities of POD were both highly improved in both high-dose group and low-dose group. The activities of POD in processing group were higher than comparison group and the activities of POD in high-dose group were higher than low-dose group. The activities of POD in low-dose group maximized in three days and restored to basically approach with the comparison group in nine days. The activities of POD in high-dose group maximized in five days and restored to basically approach with the comparison group in eleven days.3. Effect of Profenofos on CAT Activity in rapesThe activities of CAT in low-dose group were obviously higher than the comparison group, maximized in five days, gradually droped and restored to basically approach with the comparison group in nine days. The activities of CAT in high-dose group were firstly increased and later reduced, maximized in three days and lower than comparison group in five days.4. Effect of Profenofos on SOD Activity in rapes The activities of SOD were highly improved in both high-dose group and low-dose group, and the activities of SOD in high-dose group is higher than low-dose group. The activities of CAT in low-dose group maximized in five days, were equal to 1.4 times of the comparison group, gradually reduced after that and restored to basically approach with the comparison group in eleven days. The activities of SOD in high-dose group maximized in seven days, were equal to 1.7 times of the comparison group, gradually reduced after that.5. Effect of Profenofos on MDA in rapesThe content of MDA was highly improved in both high-dose group and low-dose group, and the content of MDA of in high-dose group is higher than low-dose group. On the day of the last time profenofos cream was sprayed, the content of MDA in high-dose group equalled to 1.5 times of the comparison group and the content of MDA in low-dose group equalled to 1.3 times of the comparison group. The content of MDA in two processing group had the same change tendency and both gradually reduced6. Effect of Profenofos on GSH in rapesThe content of GSH in the two processing groups had the same change tendency, both rapidly reduced in an early time and later gradually increased. The content of GSH in high-dose group minimized in seven days. The content of GSH in low-dose group minimized in five days.and restored to basically approach with the comparison group in eleven days.7. Effect of Profenofos on VC in rapesThe content of VC in the two processing groups had the same change tendency, both rapidly reduced in an early time, later gradually increased and restored to basically approach with the comparison group in seven days.Conclusion1 .The sample pretreatment and detection which this experiment used are suitable for fast examination.under the pesticide residue2. The profenofos residues in rapes degraded rapidly3. POD, SOD, CAT, MDA, GSH, VC all can serve as the biomarker under the profenofos pollution...