固体进样原子荧光用于测量农产品中的镉

摘要

本文用固体进样原子荧光（AFS）对农产品样品进行了镉含量的分析测定。本工作使用配备多孔石墨管（PGT）电热蒸发器和钨丝（TC）作为镉的捕获器的固体进样原子荧光测镉仪,通过基体处理、标准曲线策略、干扰、标样测量、比对实验及实际样品测量,考察了该仪器在农产品检测领域中的应用。该仪器最大的特点是不需要任何样品消解,可直接固体进样进行测定,测量一个样品耗时不超过5min。测量结果表明,仪器的检出限为30 ng L-1（0.3 pg）;相对标准偏差小于5%。基于其捕获、二次释放式的方式可完全分离几乎所有基体干扰,有机物、无机物对此方法无显著干扰,对多种标物测试值也都在标物的不确定度范围。用实际样品和其它仪器如电感耦合等离子体质谱（ICPMS）、石墨炉原子吸收（GFAAS）、阳极溶出（PDV）测定结果相比,固体进样检测方法与这些方法测得的数据没有显著性差异;用固体进样检测方法对实际农产品样品测定,样品的加标回收率均在90%～105%之间。该仪器检测方法操作简便、耗时短,非常适用于农产品中Cd的现场测定。%A new solid sampling Atomic Fluorescence Spectrometry was applied in determination of cadmium in agricultural products,it included a porous graphite tube(PGT) as the vaporizer and a tungsten-coil(TC) as the cadmium trap.A method for cadmium measuring in agricultural products was developed by matrix interference elimination,calibration strategy and real sample analysis,respectively.The advantage of this method was pretreatment free,which could reduce the whole analysis time to less than 5 minutes.The detection limit(DL) of this method was 30 ng L-1(0.3 pg);the relative standard deviation(RSD) was less than 5% and no significant interference was found within a 10% error range.The recoveries for some certified reference materials was good,and the spiked recoveries for some agricultural products were between 90%~105%.Furthermore,this method was compared with ICPMS,GFAAS and PDV,and no significant difference was found between them.In conclusion,the methods for detecting cadmium are quick,simple and sensitive,and can meet the requirements of detection in agricultural products.