An Analytical Method For Residue And Degradation Dynamics Of Cytosinpeptidemycin In Tobacco

Cytosinpeptidemycin is one of cytosine nucleoside antibiotics invented by College of Plant Protection, Shenyang Agricultural University. Cytosinpeptidemycin is new, low toxic and high efficient to control plant virus. Based on the situation of application of cytosinpeptidemycin in field, tobacco was choosed as representative of crop. After applying cytosinpeptidemycin and sampling according to Field Trial Standard of Pesticide Residue, pre-treatment was followed referring to the cardinal principle and procedures of residue analysis of cytosinpeptidemycin, High Performance Liquid Chromatography (HPLC) equipped with an ultraviolet (UV) analysis method were adopted to detect the residue, and then the residue analysis methods of tobacco for cytosinpeptidemycin and dynamic equation were established, in order to provide scientific evidences for the reasonable and safe application of cytosinpeptidemycin in tobacco field. The study included cytosinpeptidemycin residue analysis methods, cytosinpeptidemycin degradation dynamics in tobacco plants and soil, and the final residue of cytosinpeptidemycin in fresh tobacco leaf、dried tobacco leaf and soil. The results were as follows:In this paper, we established an analysis method detecting the cytosinpeptidemycin residue in tobacco plant and soil with High Performance Liquid Chromatography (HPLC). The HPLC testing conditions has been optimized:Stationary phase is Waters Sun Fire M, C18,5.0μm,4.6×150mm; UV detector and the detection wavelength is248nm; the mobile phase is5%methanol-water solution which pH is3.0～4.0; the method of Sample extraction, separation and purification has also been optimized; Tobacco-leaf or soil samples were extracted with acetonitrile-water and treatment of PEP-SPE column by determination with HPLC equipped with an ultraviolet (UV) detector. When the addictive amount was0.05mg/kg,2mg/kg, the average recovery of cytosinpeptidemycin in fresh tobacco leafs dried tobacco leaf and soil was87.76%～89.58%,78.72%～81.5%and91.62%～97.8%, separately, and with relative standard deviation (RSD) of4.39%～4.97%,1.62%～3.18%,3.13%～5.47%respectively, and the limits of quantification of Cinosulfuron (LOQ)was7.7ng, and the limit of detection (LOD) in tobacco and soil0.05mg/kg (L).With the mentioned method, the residual dynamics and final residual level of2%cytosinpeptidemycin AS in tobacco and soil in Shandong and Hunan Province were investigated between years2010-2011. Results indicated that the linear equation of standard solution was y=32359x+655.80(r=0.997), with the linearity of0.05-10mg/L. The decline study of cytosinpeptidemycin in tobacco was carried out, the decline curves accorded with the first-order kinetics equation, moreover it had high correlation. and the half-lives of cytosinpeptidemycin in tobacco and soil were of3.4～5.1and1.3～3.1d, respectively.The method established in this paper has high sensitivity, precision and accuracy. The result is satisfying when it is used in detecting the cytosinpeptidemycin of tobacco. This method meets the pesticide residue testing standards that must be sensitive, accurate and easy to promote.