Comparative Study on 3 Methods of Sample Pretreatment for Determination of Harmful Heavy Metals in Chuanxiong Rhizome

The methods of ① conventional wet acid-digestion,② acid-digestion assisted by microwave heating and ③ dryashing digestion were used individually for pretreatment of chuanxiong rhizome samples.The contents of Pb,Cu and Cd in each of the sample solutions were determined by GF-AAS,and contents by Hg and As by HG-AFS.As shown by the experimental results,values of recovery of Pb,Cu and Cd found in sample solution obtained by mtthods ① and ③ were in the range of 83.0% to 121.0%,while the values of recovery of Hg and As found in the same solution were much lower.In analyzing sample solution,obtained by method ②,higher recovery values ranged from 97.0%-127.0% were found for As,Cu,Cd and Mg,but low recovery value of 51.8% was found for Pb.On the whole,the digestion method ① was suitable to be used for determination of Pb by GF-AAS,the method ② was suitable for determination of Hg and As by HG-AFS,and the method ③ was preferred for determination of Cu and Cd by GF-AAS.