AFS Determination of Total Arsenic in Sugar with Microwave Assisted Sample Digestion

The sugar sample was digested with HNO3 and H2O2 in the MWS-2 microwave sample digestion system under pressure.The solution obtained was then evaporated to expel excess nitric acid.Mixed solution of thiourea and ascorbic acid was added as pre-reductant and complexing agent and the solution,after diluting to 50 mL,was used for AFS determination of arsenic under the optimum working condition of the instrument.Linear relationship between values of peak area and mass concentration of arsenic was obtained in the range within 10.0 μg·L-1,and the detection limit (3s/k) found was 0.045 μg·L-1.Two sugar samples were analyzed by this method,and recovery was tested by standard addition method using these 2 samples as matrixes,giving values of average recovery of 96.7% and 100.0%.