Study On Pesticides And Heavy Meatals Of Organic Tobacco Planted In Hunan Province

Nowadays, people pay more attention to health with the r apid economic development and improvement of living standards.To bacco, as an economic crops, the guarantee of its quality has an im portant impact on our health and domestic and foreign trade. Intern ational and domestic tobacco industry attaches great importance to t he quality of the tobacco. The pesticide residues and heavy metals in tobacco, which are critical factors to affect the quality of tobacc o. In order to ensure its quality, international and domestic tobacco industry have strengthened the monitoring of pesticide residues and heavy metals in tobacco. Thus, it is important of us to enhance th e detection of tobacco and the surrounding growing areas of pestici de residues and heavy metals in tobacco quality control. In this pap er, methods, about how to analyze the content of pesticide residues and some representative harmful heavy metals, which are establish ed in this paper. The methods are applied to organic tobacco, whic h can provide certain data for the plant and evaluation of tobacco.The main points of the study are as follows:In the first part, the significance and the research progress of pesticide residues and harmful heavy metals in tobacco were introduced, including sample pre-treatment methods and detection technologies.In the second part, a method was developed for rapid determin ation of3pesticide residues in tobacco based on gas chromatograp hy coupled with electron capture detector. After the optimization of different parameters, such as the extraction solvent,elution solvent,p urificant, pesticides were extracted from tobacco with acetonitrile, cl eaned-up on a column, packed with Florisi and neutral alumina,elut ed with hexane-ethyl acetate (98:2,V/V), and then determined by G C-ECD. The recoveries ranged from73.8%-89.4%with the relative standard deviations between5.5%-10.3%. Moreover, this method wa s used to analyse the sample planted in Hunan province.In the third part, a method was developed for rapid determination of a-BHC and y-BHC pesticide residues in tobacco based on gas chromatography.After the optimization of different parameters, such as the extraction solvent, purificant, pesticides were extracted from tobacco with hexane-acetone (1:1, V/V), cleaned-up on a column, packed with4.0g Florisi and1.0g neutral alumina and0.1g activated carbon. The recoveries ranged from75.3%-88.1%with the relative standard deviations between5.7%-11.3%.Moreover, this method was used to analyse the sample planted in Hunan province.In the fourth part, a method was developed for rapid determination of butralin in tobacco by HPLC. Pesticides were extracted from tobacco with ethyl acetate, and cleaned by sodium chloride which the concentration was5%. Then the extract was purified by methylene chloride through liquid-liquid distribution. The recoveries ranged from75.2%-89.4%with the relative standard deviations between4.5%-7.8%. The accuracy and precision can satisfy the requirement of butralin in the tobacco. Moreover, this method was used to analyse the sample planted in Hunan province.In the fifth part, a method with HNO3-H2O2as digestion and determination of some harmful heavy metals such as As、Pb、Cd、Cr with ICP-AES was studied. The recoveries of the four heavy metals ranged from87.6%-97.4%with the relative standard deviations between1.6-4.3%. The accuracy and precision can satisfy the requirements of heavy metals in the tobacco.