Speciation of mercury in water and freshwater fish samples by a two-step solidified floating organic drop microextraction with electrothermal atomic absorption spectrometry

• Published in: Food chemistry 2019-03, Vol.277, p.496-503
• Main Authors: Sakanupongkul, Apinya, Sananmuang, Ratana, Udnan, Yuthapong, Ampiah-Bonney, Richmond J., Chaiyasith, Wipharat Chuachuad
• Format: Article
• Language: English
• Subjects: 4-Nitro-o-phenylenediamine (4-NOPD); Animals; Calibration; Chelating Agents - chemistry; Electrothermal atomic absorption spectrometry; Fishes; Fresh Water - chemistry; Freshwater fish samples; Mercury - analysis; Mercury speciation; Methylmercury Compounds - analysis; Phenylenediamines - chemistry; Seafood - analysis; Solidified floating organic drop microextraction (SFODME); Spectrophotometry, Atomic; Water - chemistry; Water samples
• ISSN: 0308-8146; 1873-7072
• DOI: 10.1016/j.foodchem.2018.10.131

•New and simple two-step SFODME for speciation of mercury by ETAAS was developed.•CH3Hg was extracted into 1-undecanol and Hg(II) was then complexed with 4-NOPD.•Method was applied to mercury speciation in water and fish samples.•Method used small volume of organic solvent, environmental friendly and high EF. A new and simple two-step SFODME using 4-nitro-o-phenylenediamine (4-NOPD) as a chelating agent was developed for mercury speciation in water and fish samples by ETAAS. For the first step, methylmercury was extracted into 1-undecanol and for the second step, the Hg(II) remaining in the sample solution was complexed with 4-NOPD and then extracted into 1-undecanol. Under the optimized conditions, the calibration graphs of Hg(II) and methylmercury were linear in the range of 0.83–8.0 µg L−1 and 0.78–8.0 µg L−1, with the LOD of 0.25 µg L−1 and 0.24 µg L−1 and the enrichment factor were 25.7 and 32.2, respectively. The %RSDs was in the range of 2.0–4.4% at concentrations of 0.5 and 4.0 µg L−1 (n = 5). The proposed method was successfully applied to mercury speciation in water and fish samples. The accuracy of method, tested by the analysis of SRM 1566b and DORM-4 was in good agreement with the certified values.