Study On The Storage Stability Of Polyoxins B In Panax Ginseng Residual Samples

Alternaria panax whetz is one of the most common and most harmful plant diseases of Panax ginseng.In generally,the incidence rate is between 20% and 30%,and it can reach more than 90% in severe cases.Polyoxins B has been considered to be the most successful agricultural antibiotics,and widely used to control the Alternaria panax whetz with excellent control effects.A simple sample pre-treatment procedure which was vortex extraction with formic acidwater and then the extraction was purified by needle filter was established.And a sensitive and reliable HPLC-MS/MS method was optimized for polyoxins B residue in Panax ginseng samples(fresh Panax ginseng,Panax ginseng plant)and Panax ginseng soil residues.At spiked levels of 0.2 mg/kg,2 mg/kg and 5 mg/kg polyoxins B,the average recoveries of the method were 76.9%~84.1%(6.0%~10.1% of RSD,fresh Panax ginseng),74.7%~94.7%(1.3%~4.2% of RSD,Panax ginseng plants)and 74.1%~79.2%(1.8%~9.2% of RSD,Panax ginseng soil).The minimum detection limits were 0.41 ng,0.05 ng,and 0.05 ng,respectively,and the quantitative detection line was 0.28 mg/kg,0.05 mg/kg,and 0.02 mg/kg,respectively,to polyoxins B in three matrixes(fresh Panax ginseng,Panax ginseng plant and Panax ginseng soil).By the test to actual sample,the analytical method was exhibited good sensitivity and accuracy.The sample pretreatment procedure is simple in operation,saves solvent,and efficiency,which can meet the requirements of pesticide residue analysis.Based on the established residue analysis method,the low temperature storage stability of polyoxins B in three matrixes was carried out.The obtained results indicated that the stable storage period was 10 months(300 days)to 1 mg/kg ~2 mg/kg polyoxins B in Panax ginseng and Panax ginseng plants and the stable storage periods of 1 mg/kg and 2 mg/kg polyoxins B in Panax ginseng soil were 120 d at-18 ? and-20 ? storage conditions.