硝酸介质-水载流-原子荧光光谱法测定膨化食品中痕量铅

Determination of trace lead in puffed food by nitric acid medium water carrier current atomic fluorescence spectrometry

目的:建立硝酸介质下原子荧光光谱法测定膨化食品中痕量铅的分析方法。方法:通过湿法消解样品,用9%(体积分数)硝酸介质提取测定膨化食品中铅的含量。比较了干法灰化和湿法消解的优劣,考察了盐酸和硝酸介质提取的效果,讨论了硝酸酸度、硼氢化钾浓度、氢氧化钠、铁氰化钾、铅增敏剂的用量以及共存离子Cu^(2+)、Fe^(3+)、Al^(3+)、Mn^(2+)的干扰。结果:0.1 mg/L以上的Cu^(2+)、Al^(3+)对铅的测定产生负干扰,方法检出限为3.55μg/kg,样品的加标回收率为92.7%~104.2%。结论:该方法前处理操作方便、检测速度快、灵敏度高,适合大批量膨化食品中痕量铅的测定。

Objective:a method for the determination of trace lead in puffed food by atomic fluorescence spectrometry in nitric acid medium was established.Methods:the samples were digested by wet method and extracted with 9%(volume fraction)nitric acid medium to determine the content of lead in puffed food.The advantages and disadvantages of dry ashing and wet digestion were compared.The extraction effects of hydrochloric acid and nitric acid were investigated.The acidity of nitric acid,the concentration of potassium borohydride,the dosage of sodium hydroxide,potassium ferricyanide and lead stabilizer,and the interference of coexisting ions Cu^(2+),Fe^(3+),Al^(3+)and Mn^(2+)were discussed.Results:Cu^(2+)and Al^(3+)above 0.1 mg/L had negative interference with the determination of lead,and the detection limit was 3.55μg/kg,the recovery rate of the sample is 92.7%~104.2%.Conclusion:the method has the advantages of convenient pretreatment,fast detection speed and high sensitivity.It is suitable for the determination of trace lead in bulk puffed food.