Study On Determination Of Metaxyl In Wine

Metaxyl is a low poisonous bactericide which can be absorbed by root, culm and foliage, it can transfer to each apparatus with water in plant and can be used to dispose culm and foliage, seed and soil to prevent some diseases of grape. The residual analytical method of this bactericide is singularly reported, its national standard method has not been established yet.The purpose of the paper was to set up the standard method for measuring metaxyl in table wine. The paper mainly describes the sample-pretreated methods for analyzing metaxyl in table wines in combination with a gas chromatographic/mass spectrometric (GC/MS) system. Parameters were optimized of the sample-pretreated methods including liquid/liquid extraction, accelerate solvent extraction, solid phase micro extraction and solid/liquid extraction. Furthermore, the method for determining metaxyl in grape juice was established. Following the upward study, the results were as follows:The optimized parameters of the accelerate solvent extraction of table wine were: hexane:acetone=1:1,pressure was 1200psi,temprature was 50℃,time was 10min,circle was 2 times. Using the established method, the recoveries and the precision of metaxyl were between 90.50～101.2% and 1.46～3.28%,The limits of detection were 0.01μg/mL.The optimized parameters of the liquid/liquid extraction of table wine were: the wine samples were extracted by acetone and ethyl acetate, the recoveries and the precision of metaxyl were between 74.0～112.8% and 1.54～3.58%,The limits of detection were higher than 0.05μg/mL.The optimized parameters of the solid phase microextraction of table wine were: the wine samples were extracted by dichloromethane, the extracted liquid passed the C18 columella,the recoveries and the precision of solid phase microextraction were between 79.12～87.2% and 1.54～3.58%,The limits of detection were higher than 0.05μg/mL.SPME was not fit for extracting metaxyl from wine.Stability test indicated: The standard solution of metaxyl (diluted with dichloromethane ) at 4.85μg/mL can be stored two months at 4℃;Metaxyl in extract solution of wine can be stored two weeks at 4℃or at -20℃.The developed standard method of determination of metaxyyl in table wines was simple, fast, reproducible and accurate, and the method could be applicable for routine determination of metaxyl in table wines.