Detection Technique For Maleic Hydrazide Residues In Tobacco Leaves

Tobacco is one of the most important economic crops in our country,which occupied an important position in the national fiscal revenue.In order to improve the yield and quality of tobacco,a large number of farmers spraying pesticides in the process of planting tobacco,resulting in pesticide residues into tobacco leaves,and caused a potential threat to the health of smokers.Maleic hydrazide as a sprout inhibitor,mainly inhibit the growth of tobacco axillary bud.Therefore,it is very necessary to establish the detection technology of the residue of maleic hydrazide in tobacco leaves.Extracting pesticide residues in tobacco leaves of maleic hydrazide by ultrasonic,the first to do single factor experiments to obtain various factors on the impact of extract content of maleic hydrazide in tobacco leaves.Applicating UV spectrophotometry determined the content of maleic hydrazide in tobacco and optimized by response surface method,the factors were obtained:liquid ratio>ultrasonic power>ultrasonic time>particle size.The optimal solution for extraction were ultrasonic power of 220w,solid-liquid ratio of 14g/mL,ultrasonic time of 55min,crushed particle size of 80 mesh.The establishment of pesticide residues maleic hydrazide in tobacco ultrasonic extraction-ultraviolet spectrophotometry method by experiments,maleic hydrazide recovery were between 96.64%~98.02%,RSD were between 4.62%-7.38%,and the detection limit of this method was 8.8?g/g.With supercritical carbon dioxide extracting pesticide residues maleic hydrazide in tobacco,obtained various factors on the impact of extract content of maleic hydrazide in tobacco leaves by single factor experiments.Then determined maleic hydrazide content by HPLC in tobacco.It optimized the experimental technique of supercritical fluid extraction of tobacco pesticide maleic hydrazide in tobacco by orthogonal experiment and the order of each factor's impact was pressure>temperature>time>CO2 flow.The optimum extraction process for the extraction temperature was 55 °C.extraction pressure was 20 MPa,extraction time was 100min,CO2 flow was 23g/min,entrainer methanol:isopropanol wasn1:1(V:V);and entrainer The amount was 4%.The establishment of Supercritical Fluid Extraction-High Performance Liquid Chromatography determining pesticide residues maleic hydrazide in tobacco leaves,obtained maleic hydrazide recovery were between 94.08%-97.86%,RSD were between 2.43%~5.67%,and the detection limit of this method was 2.7?g/g by experiment.By comparing the two kinds of analysis methods,it suggested that Supercritical Fluid Extraction-High Performance Liquid Chromatography the detection time was short,the process was simple,detection limits was lower and more practical than Ultrasonic Extraction-Ultraviolet Spectrophotometry.