顶空-气相色谱法测定葡萄中乙烯利的残留量

GC Determination of Residual Amount of Ethephon in Grapes with Headspace

称取葡萄样品于预先加入氯化钠的顶空瓶中,再加入饱和氢氧化钾溶液,采用顶空-气相色谱法测定上述混合液中乙烯利的残留量。顶空温度为75℃,顶空时间为90min,采用HP-5色谱柱(30m×0.32mm,0.25μm)分离,氢火焰离子化检测器测定。乙烯利的质量浓度在0.500~50.0mg·L^-1内与其对应的峰面积呈线性关系,检出限(3S/N)为0.010 0mg·kg^-1。方法用于葡萄样品的分析,加标回收率为99.9%~104%,测定值的相对标准偏差(n=6)为1.9%~3.5%。

The grape sample was weighed and put into the headspace bottle with sodium chloride added in advance.The saturated potassium hydroxide solution was added then.GC was applied to the determination of residual amount of ethephon in the above mixture with headspace.The temperature and time of headspace were set at 75℃and 90 min.The analyte was separated on HP-5 chromatographic column(30 m×0.32 mm,0.25μm)and detected by hydrogen flame ionization detector.Linear relationship between values of peak area and mass concentration of ethephon was kept in the range of 0.500-50.0 mg·L^-1,with detection limit(3 S/N)of0.010 0 mg·kg^-1.The proposed method was applied to the analysis of the grape sample,giving values of recovery found by standard addition method and RSDs(n= 6)of determined values in the ranges of 99.9%-104% and1.9%-3.5%respectively.