Sample Preparation Methods for Organic Arsenic Species (arsenobetain, (CH3)3As+CH2COO−) in Tuna Fish Samples Followed by HG-QFAAS, GF-AAS, and ICP-MS Measurements

Determination of total arsenic was strongly influenced by the properties of the spesies. In a sample of tuna fish, the total arsenic concentration (90-95%) mostly comes from organic arsenic species, arsenobetain (AB). AB in particular, was not decomposed to arsenate which can lead to a serious error in quantification when a hydride generator step is additionally used in the analysis scheme. This research was done to compare three different types of sample preparations, namely dry ashing, water extraction, and microwave digestion, for measuring the total arsenic using HG-QF-AAS, GF-AAS and ICP-MS measurements. HG-QF-AAS and ICP-MS gave similar concentrations of total arsenic in a tuna fish sample, which were 3.49±0.08 μg g-1 and 3.56±0.014 μg g-1, respectively. Meanwhile, the result from GF-AAS measurements was about a half of the others. The results of this research can be used as a reference for determination of total arsenic in tuna fish samples.