Determination of Arsenic and Selenium in Food using a Microwave Digestion–Dry Ash Preparation and Flow Injection Hydride Generation Atomic Absorption Spectrometry

A flow injection hydride generation atomic absorption spectrometry method was developed for determination of total arsenic and selenium content in food. The availability of arsenic and selenium for hydride generation was ensured by using a combination microwave digestion–dry ash preparation that destroyed the organic matrix including refractory organometallic compounds present in some foods. Hydroxylamine was used to enhance arsenic sensitivity by approximately 15%. The ratio of peak area to peak height was used to identify irregular peak profiles and potential interference. Method validation was performed with 21 foods and nine reference materials. Arsenic fortification recovery ranged from 96 to 105% in foods. Selenium fortification recovery ranged from 88 to 107% in foods. Inorganic species were used for fortification. Nine food-related reference materials were analyzed with satisfactory results. Estimated quantitation limits for a 1 g test portion were 0.01 mg/kg for arsenic and 0.02 mg/kg for selenium. Extensive quality control (QC) measures were included to support method performance.