Abstract
A rapid and precise method for the determination of microamounts of arsenic in fats and oils has been studied. The samples were decomposed by wet-digestion procedure using sulfuric acid and hydrogen peroxide (30%), then, arsenic in the decomposed solution were coprecipitated as the complexes with ferric hydroxide. The coprecipitations were reduced to gaseous arsine by zinc in an acid medium, then, arsine gases absorbed into solution of silver diethyldithio carbamate dissolved in pyridine. The absorbance of the arsine reacts solution were measured at about 530 nm. The most suitable pH for the coprecipitation of arsenic was about 9.
The proposed method was evaluated with respect to recovery and reproducibility by earring out collaborative studies on the samples which were prepared by adding known amounts of arsenic to soybean oil. The results thus obtained showed good agreement with the theoretical values and satisfactory reproducibility.
