Rapid Determination Trace Of Arsenic In Food Using Hydride Generation-Atomic Fluorescence Spectrometry

There is a continuing interesting challenge in the trace determination of arsenic because of its high toxicity and ability to bioaccumulate in many organisms and its abundance in all environmental compartments. The high toxicity of arsenic (As^III and As^V, which together constitute inorganic arsenic) and some of its compounds requires its determination at very low concentrations in a variety of samples. Since the arsenic levels in real samples are very low, state-of-the-art enrichment methods and instrumentation are required. Hydride generation atomic fluorescence spectrometry (HG-AFS) has been used for determination of hydride-forming elements because of its high sensitivity, simplicity, and low costs.In Chapter I, the methods for determination of arsenic, hydride generation and atomic fluorescence spectrometry with its research and application were reviewed.In Chapter II, a novel pretreatment method without evaporating and exhausting the excess nitric acid used for digesting biological sample was developed based on the evaluation of the interference of nitrite and nitric acid on the determination of arsenic using HG-AFS. After microwave sample digestion, the interference from nitrite ion generated during sample digestion was removed by adding urea. The excessive nitric acid was neutralized by sodium hydroxide. L-cysteine was used to prereduce As(V) to As(III) in low hydrochloric acid concentration. The pretreatment mothod is fast and accurate and was successfully applied to the determinationof As in a variety of biological samples. In addition, the proposed pretreatment method can prevent sample contamination and loss during exhausting the excess nitric acid . The experimental environment and hazards to staff's health are also greatly improved.