Analysis Of10Pesticides Residues In Agricultural Products And Soil Of China And Sudan

In the present study, a quick, easy, cheap, effective, rugged and safe (QuEChERS) method based on liquid chromatography tandem mass spectrometry (LC-MS-MS) for simultaneous determination of four fungicides (fluopyram, tebuconazole, trifloxystrobin and trifloxystrobin acid) in vegetables (tomato, and cowpea), fruits (pear, grape, apple, and watermelon), and soil was developed. The fungicides were extracted from six fruits and vegetables matrices using acetonitrile and subsequently cleaned up only using octadecylsilance (C18) as sorbent prior to UPLC-MS/MS analysis. The target compounds were separated achieved in less than3.0min and detected with an electrospray ionization source in positive mode (ESI+). The limits of detection (LOD) and limits of quantification (LOQ) were obtained using the peak areas of the product ion obtained through MS/MS mode. The limits of detection (LOD) ranged between0.2to2μg kg-1, while the limits of quantification (LOQs) ranged between the0.5to7μg kg-1in different matrices. The recoveries and relative standard deviations (RSDs) were satisfying in different matrices at three spiked levels (0.01,0.1and1mg kg-1) by matrix-matched standards. The recovery results were from71.7%to116.4%with RSD in the range of1.3%to20%.The degradation of fluopyram and tebuconazole in tomato and soil also were investigated, with correlation Coefficients (R2) between0.9761to0.9999for fluopyram and tebuconazole in tomato and soil matrix. The dissipation half-lives of fluopyram in tomato and soil were7.0-24.5days,2.8-13.8days and8.9-21.9days for Shandong, Henan and Beijing respectively in two years2012and2013. The final residues of floupyram and tebuconazole ranged from0.12to1.35mg/kg in Shandong,1.13to1.53mg/kg in Henan and<0.06to1.221mg/kg in Beijing samples respectively.The degradation results of fluopyram and trifloxystrobin in watermelon and soil, the dissipation half-lives of fluopyram and trifloxystrobin in watermelon and soil were ranged between3.1and14.1days for Anhui and1.9to8.1days to Beijing for two years2011and2012. The final residues of floupyram and trifloxystrobin ranged from0.01to0.132mg/kg for Anhui and0.01to0.083mg/kg for Beijing samples respectively.For the second part of this thesis, the simultaneous residue analysis of six insecticides (imidacloprid, acetamiprid, thiacloprid, thiamethoxam, clothianidin and flonicamid) in Okra and Roselle was developed. The determination of the target compounds was achieved in less than2.0min using an electrospray ionization source in positive mode (ESI+) for imidacloprid, acetamiprid, thiacloprid, thiamethoxam, clothianidin but negative mode (ESI-) for flonicamid. The limits of quantification (LOQ) for the six insecticides ranged between the0.11to5.9kg-1, while the limits of detection (LOD) were ranged between0.09to17.5μg/kg-1in all matrices. The overall average recoveries in Roselle and Okra at three spiked levels (0.1,0.5and1mg L-1) and (0.01,0.1, and1mg L-1) ranged from72.4%to105.1%with RSD in the range of2.2-20%for all analytes. This study provides a theoretical basis to recommend MRLs and analytical method for these insecticides in Okra and Roselle.