GF-AAS Determination of Fe in Sulfur with Microwave Assisted Digestion

Sample of sulfur was digested with nitric acid using microwave digestion method. The content of Fe in the sample solution was determined by GF-AAS. Solution of 1 g·L-1 magnesium nitrate (10 μL) was used as matrix modifier. The ashing temperature was 1 200 ℃ and the atomization temperature was 2 000 ℃. Linear relationship between values of absorbance and mass concentration of Fe was kept in the range of 3.0-25.0 μg·L-1, with detection limit (3s/k) of 0.5 μg·L-1. Precision of the method was tested at the sample of industrial sulfur, value of RSD (n=6) found was 2.2%. Test for recovery was performed by standard addition method, giving recovery in the range of 99.5%-101%.