离子色谱法测定豇豆和苦瓜中对氯苯氧乙酸的残留量

摘要

采用离子色谱法测定豇豆和苦瓜中对氯苯氧乙酸的残留量.豇豆和苦瓜样品采用1.8 mmol·L-1碳酸钠-1.7 mmol·L-1碳酸氢钠溶液超声提取,固相萃取C18小柱净化.以1.8 mmol·L-1碳酸钠-1.7 mmol·L-1碳酸氢钠溶液为流动相,紫外检测器测定.对氯苯氧乙酸的质量浓度在0.05~25.0 mg·L-1内与其对应的峰面积呈线性关系,对氯苯氧乙酸在豇豆和苦瓜中的检出限(3S/N)依次为0.04,0.03 mg·kg-1.以空白样品为基体进行加标回收试验,所得回收率在96.7%~109%之间,测定值的相对标准偏差(n=5)在4.7%~7.7%之间.%IC was applied to the determination of residual amount of 4-chlorophenoxyacetic acid in cowpea and bitter gourd.The sample of cowpea and bitter gourd was extracted ultrasonically with mixture of 1.8 mmol·L-1 Na2 CO3 and 1 .7 mmol·L-1 NaHCO3 solution,and then purified with SPE C18 colunm.Mixture of 1 .8 mmol·L-1 Na2 CO3 and 1 .7 mmol · L-1 NaHCO3 solution was used as mobile phase,and UV detector was used in determination.Linear relationship between values of peak area and mass concentration of 4-chlorophenoxyacetic acid was kept in the range of 0.05-25.0 mg·L-1 ,with detection limits (3S/N)in cowpea and bitter gourd of 0.04, 0.03 mg·kg-1 respectively.On the base of blank sample,test for recovery was made by standard addition method;values of recovery found were in the range of 96.7%-109%,with RSD′s (n= 5)in the range of 4.7%-7.7%.