Determination of Arsenic in Milk Powder by Atomic Absorption Spectrophotometry

Abstract

Determination of micro amounts of arsenic in milk powder was carried out by atomic absorption spectrophotometry attaching arsine generating apparatus. About 1.0g of sample was dry-ashed at about 600°C in the presence of magnesium salts. The addition of magnesium salt was to prevent the sublimation of arsenic at high-temperatures' dry-ashing. The ashes were dissolved in hydrochloric acid and the arsenate was changed to arsine gas by potassium iodide, stannous chloride, and zinc powder. And the arsine gas conducted to the atomic absorption spectrophotometer. The absorbance was proportional to arsenic over a wide range of its content. This method was successfully applied to the determination of the arsenic content in commercial milk powder by which obtained values were within 0.05 to 0.13 ppm.