Chelex-100树脂对铅、镉、钠的吸附性能及其应用于原子吸收光谱法测定高盐食品中铅、镉含量

Adsorbility of Lead, Cadmium and Sodium on the Chelating Resin, Chelex-100 and Its Application to AAS Determination of Lead, Cadmium in High-Salt Food

摘要: 对铅、镉和钠在Chelex-100树脂上于不同pH值的介质中的分配系数(Kd)和吸附容量进行了研究。结果表明:在pH 1~8的介质中Na+的Kd<3,即在Chelex-100树脂上无吸附;在pH>4的介质中,Pb2+和Cd2+的Kd>104,即强吸附于Chelex-100树脂上;而用0.16 mol·L-1硝酸溶液可将吸附于树脂上的Pb2+和Cd2+完全洗脱下来。在此基础上提出了一种Chelex-100树脂分离原子吸收光谱法测定高盐食品中重金属元素含量的方法。方法用于高盐食品分析,加标回收率在93.1%~102%之间,测定值的相对标准偏差(n=5)在0.5%~3.4%之间。

Abstract: The distribution coefficients (Kd) and adsorption capacity of Pb2+, Cd2+ and Na+ on Chelex-100, a chelating resin in media of different pH values were studied. It was found that in a medium of pH 1-8, the Kd of Na+ was less than 3, while the Kd of Pb2+ and Cd2+ were more than 104, hence, Pb2+ and Cd2+ were adsorbed strongly on the resin, while Na+ was not adsorbed. And Pb2+ and Cd2+ were completely eluted from resin with 0.16 mol·L-1 HNO3 as eluent. Based on these facts, a method of AAS determination of cadmium and lead in high-salt food was proposed. Sample of high-salt food was analyzed by the proposed method, giving values of recovery in the range of 93.1%-102%, and values of RSD′s (n=5) in the range of 0.5%-3.4%.