FAAS Determination of Cobalt in Soil with Microwave Assisted Sample Digestion

The soil sample was digested with a mixture solution of HNO3,HCl,and HF(5+3+2) by microwave assisted sample digestion,and Co in the solution was determined by FAAS.The choices of digestion system,digestion time,and digestion temperature were studied and optimized.The proposed method was used in the determination of cobalt in soil,giving values of recovery in the range of 96%-106%.Analytical results of environmental soil sample obtained by microwave assisted digestion were compared with those obtained by the conventional digestion with acid mixture heated on electric heating plate,as verified by t-test at the confidence level of a=0.05,no significant difference was found between the two digestion methods.