The use of HPLC-NAA and HPLC-ICP-MS for the speciation of As in infant food

Arsenic and its inorganic species: As (III), As (V), dimethylarsenic acid (DMA) and monomethylarsenic acid (MMA) were determined in hypoallergenic formulas and grain porridges commercially available on Polish market, dedicated for infant 0-8 months. After quantitative extraction with 0.5% HNO3, separation of individual species was performed by high performance liquid chromatography (HPLC), and their determination by neutron activation analysis (NAA) and inductively coupled plasma mass spectrometry (ICP-MS). Due to relatively low content of As in the analysed samples, it was only possible to determine DMA using the HPLC-ICP-MS mode. HPLC separation coupled with off-line determination by NAA enabled the determination of more extracted As species (especially inorganic) with good accuracy. Certified reference material (CRM) Rice Flour SRM 1568b (NIST) was used for the validation of both procedures.