Comparison of some wet digestion and dry ashing methods for voltammetric trace element analysis

Abstract

Several wet digestion and dry ashing methods were compared for the precise and accurate determination of some trace elements in biological and environmental materials. The wet digestion methods were generally faster than the dry ashing methods, but required the use of large amounts of reagents and, therefore, gave higher blank contributions for some elements. The main advantages of the dry ashing method were the lower blank levels, improved (lower) background current and its ability to handle considerably larger amounts of sample. However, careful dissolution of the sample ash in a suitable reagent was necessary. Under suitable conditions, both decomposition methods allowed the reliable voltammetric determination of trace elements in biological and environmental materials with relative standard deviations of between 1 and 3%. The ultimate choice of decomposition method was influenced by the amount of sample available, the nature of the sample, the sample matrix and the analysis time available.