Sample preparation for arsenic speciation analysis in baby food by generation of substituted arsines with atomic absorption spectrometry detection

摘要

Abstract A slurry sampling procedure for arsenic speciation analysis in baby food by arsane generation, cryogenic trapping and detection with atomic absorption spectrometry is presented. Several procedures were tested for slurry preparation, including different reagents (HNO3, HCl and tetramethylammonium hydroxide – TMAH) and their concentrations, water bath heating and ultrasound-assisted agitation. The best results for inorganic arsenic (iAs) and dimethylarsinate (DMA) were reached when using 3molL?1 HCl under heating and ultrasound-assisted agitation. The developed method was applied for the analysis of five porridge powder and six baby meal samples. The trueness of the method was checked with a certified reference material (CRM) of total arsenic (tAs), iAs and DMA in rice (ERM-BC211). Arsenic recoveries (mass balance) for all samples and CRM were performed by the determination of the tAs by inductively coupled plasma mass spectrometry (ICP-MS) after microwave-assisted digestion and its comparison against the sum of the results from the speciation analysis. The relative limits of detection were 0.44, 0.24 and 0.16μgkg?1 for iAs, methylarsonate and DMA, respectively. The concentrations of the most toxic arsenic species (iAs) in the analyzed baby food samples ranged between 4.2 and 99μgkg?1 which were below the limits of 300, 200 and 100μgkg?1 set by the Brazilian, Chinese and European legislation, respectively. Graphical abstract Display Omitted Highlights ? A slurry preparation procedure for arsenic speciation in baby food is proposed. ? Hydride generation-cryotrapping-atomic absorption spectrometry is used. ? Cryotrapping device allows iAs, MMA and DMA separation. ? For slurry preparation 3molL?1 HCl provides recoveries of almost 100% for As species. <