Study On The Analysis Method And Residue Digestion Of The 6 Components Of Pyrethrin On Traditional Chinese Medicinal Material Lycium Barbarum

Pyrethrins,known as natural pyrethrins,is an ingredient of Pyreyhrum cineriifoliun Trebr with obvious anti-insect activity.It is a typical nerve agent and consists of six components including pyrethrins I,pyrethrins II,cinerin I,cinerin II,jasmolin I and jasmonin II.Pyrethrins has a lot of advantages,such as good anti-insect activity,broad insecticidal spectrum,low residue after application,low toxicity to mammals and livestock,safe for plants and environment.Because pyrethrins is composed of six substances with good insecticidal activity and is not easy for insects to develop resistance,it is used to control pests on goji plants.This paper aims to establish a residual analytical approach for the simultaneous determination of six components of pyrethrins in fresh goji berries and dried goji berries by gas chromatography with tandem mass spectrometry（GC-MS/MS）.And field trials including terminal residues and dissipation dynamics experiments are carried out by spraying 1.5%pyrethrins aqueous emulsion on goji berries in Ningxia,Hebei,Qinghai,Inner Mongolia and Gansu.The results might provide data support for the residual analysis of six components of pyrethrins in other crops and proper application and safety evaluation of pyrethrins in goji plants.Six components of pyrethrins were separated on a DB-5MS（30 m×0.25 mm,0.25μm）column.The fresh and dried goji berry samples were extracted with acetonitrile.Then the mixture was vortexed,centrifuged,evaporated and purified by20 mg of C₁₈and 20 mg of PSA.The residues were dissolved in acetone and analysed by GC-MS/MS.All pyrethrins components had good linearities（R²>0.9904）.The limits of detection and limits of quantitation of six analytes in the two matrices were0.24-2.1μg/kg and 0.8-7μg/kg,respectively.The average recoveries of pyrethrin I,pyrethrin II,citrinin I,citrinin II,jasmonin I,and jasmonin II were 94.6-100.6%,94.3-105.7%,88.7-102.4%,95.0-103.7%,97.2-106.3%,and 93.2-103.4%in fresh and dried goji berries,respectively.The relative standard deviations were 1.1-7.7%,3.6-6.9%,2.7-4.7%,2.1-4.8%,0.9-6.0%和1.4-7.1%.The method had been successfully applied to determine the concentrations of six components of pyrethrins in fresh and dried goji berry samples collected from the dissipation dynamics and terminal residue trails.In the dissipation dynamic experiment,the six components of pyrethrins could not be detected in all fresh goji berry samples.The data could not be calculated by the first-order kinetic equation and only be used for monitoring.In the terminal residue experiment,the concentrations of pyrethrins,sum of concentrations of six pyrethrins components,in fresh and dried goji berry samples at harvest were<20-304μg/kg and<20-60μg/kg,respectively.Moreover,the risk assessment results indicate that the risk quotient values were far less than 100%which means the potential dietary risk of pyrethrins on goji berries could be negligible for Chinese consumers.This study could provide some data for the determination of pyrethrin residues in other crops and the proper application and safety evaluation of pyrethrins in goji plants.