中文摘要：

为了避免繁琐、耗时的“赶酸”操作，研究了尿素结合NaOH除去微波消解液中过量的HNO3和HNO2的干扰，继用L-半胱氨酸在低酸度下将As（Ⅳ）还原为As（Ⅲ）的样品消化和预还原方法。用氢化物发生-原子荧光法准确、快速地测定了食品中痕量砷。该方法的检出限为0．03μg/L；连续11次测定4μg／LA（Ⅲ）标准溶液的相对标准偏差为1．6％；测定国家标准物质的结果与标准值非常吻合。

英文摘要：

Abstract To avoid time-consuming procedure for evporating excessive nitric acid added for microwave digestion and nitrite ion generated during digestion, a rapid pretreatment method was developed. After microwave digestion, the nitrite ion was removed by adding urea and the nitric acid was neutralized by sodium hydroxide. L-cysteine was used to prereduce As （Ⅴ） to As （Ⅲ） with hydrochloric acid in low concentration. The proposed pretreatment mothod was successfully applied to the determination of trace amount of arsenic in foods with hydride generation-atomic fluorescence spectrometry. The method is fast and can prevent sample contamination and loss. The detection limit was 0.03 μg/L. The relative standard deviation for 11 determinations of a solution containing 4 μg/L arsenic was 1.6%. Results obtained for both standard reference materials agreed well with the certified values with a good precision.