Abstract: An analytical method for the determination of the total arsenic (As) concentration of edible fungi using hydride generation-microwave plasma-atomic emission spectroscopy (MP-AES) was established. After wet digestion of edible fungi samples, arsenic (V) was reduced to arsenic (III) using a pre-reducing solution (containing 50 g/L thiourea and 10 g/L potassium iodide). As (III) was transformed into gaseous arsenic trihydride using a multimode sample introduction system and detected by HG-MP-AES. The spectral line of As at 188.979 nm was selected as the analytical line to avoid spectral overlap interference. The background interference was corrected by using the fast linear interference correction model. The limit of detection for As was determined to be 0.93 μg/L. Total As levels of the different varieties of edible fungi samples tested ranged from 0.087 to 0.482 mg/kg. The results of this method for total arsenic in the standard reference material GBW10022 (garlic powder) were consistent with the certified value, indicating that this method is accurate. To sum up, MP-AES proved to be a fast, accurate and reliable high-throughput method for the determination of total arsenic in edible fungi samples. MP-AES used nitrogen generated from air with a nitrogen generator as the plasma working gas, reducing the cost.

Key words: edible fungi; total arsenic; microwave plasma-atomic emission spectroscopy; hydride generation; multimode sample introduction system; fast linear interference correction