石墨炉原子吸收光谱法测定高钙食品中镉

GF-AAS Determination of Cadmium in High Calcium Food

将高钙食品置于瓷坩埚中,加入硝酸低温加热消解并蒸至近干,残渣用硝酸（1＋1）溶液溶解,并补足至25 mL。采用石墨炉原子吸收光谱法测定试液中镉的含量。以硝酸镁为基体改进剂,选择灰化温度和原子化温度分别为750℃和1 100℃。镉的质量浓度在5μg·L^-1以内呈线性,方法的检出限（3s/k）为3.3μg·kg^-1。方法用于高钙食品样品分析,加标回收率在90.0%-103.3%之间,相对标准偏差（n=7）在2%-3%。

Sample of food with high calcium content was digested with HNO3 in a porcelain crucible by heating at low temperature,and evaporated to near dryness.The residue was taken up with HNO3（1＋99）,and made up to 25 mL.Calcium in the sample solution was then determined by GF-AAS with Mg（NO3）2 added as matrix modifier.Temperatures of 750 ℃ and 1 100 ℃ were chosen for ashing and atomization respectively in the operation of graphite furnace.Linearity range of calcium was kept in the range within 5 μg·L^-1 with detection limit（3s/k） of the method 3.3 μg·kg^-1.The proposed method was applied to the analysis of samples of calcium supplementary food,and values of recovery obtained by standard addition method were in the range of 90.0%-103.3%.Values of RSD′s（n=7） found were ranged from 2% to 3%.