火焰原子吸收光谱法测定海木耳中3种重金属

FAAS Determination of 3 Heavy Metals in Sarcodia Ceylonensis

采用火焰原子吸收光谱法(FAAS)测定了海木耳中3种重金属(铜、铅和镉)。将海木耳样品去柄后剪碎并在烘箱中烘干至恒重,称取干燥样品1.0000g,分次用硝酸-高氯酸(9+1)混合酸10mL消解至溶解完全,定容至10mL,用FAAS按选定的仪器工作条件测定其中的铜、铅和镉量。对同一样品的上述3元素作5次平行测定,测定值的相对标准偏差依次为2.0%,3.2%及2.5%。用标准加入法测得方法的回收率为95.4%(铜),95.3%(铅)及103.0%(镉)。在测定结果中除铜量外,铅量及镉量均分别超过国家标准规定允许量的34.3倍和13.9倍。

3 Heavy metals,i.e.,Cu.Pb and Cd,in Sarcodia ceylonensis were determined by FAAS.Sample of Sarcodia ceylonensis was cut into pieces and dried in an oven to constant weight.For determination of Cu, 1.000 0 g of the dried sample was taken and digested with 10 mL portions of mixed acid of HNO_3-HClO_4（9 ＋ 1） until complete dissolution was attained.The solution was made up to 10 mL in a volumetric flask and used for FAAS analysis.In 5 determinations for the 3 elements in a same sample,values of RSD（n=5） found were 2.0%, 3.2%and 2.5%for Cu,Pb and Cd respectively.Values of recovery found by standard addition method were 95.4%（for Cu）,95.3%（for Pb） and 103.0%（for Cd）.It was found that besides the content of copper,the contenls of Pb and Cd were 34.3 times and 13.9 times higher than the specified tolerable levels given in the GB standards.