Determination of Cl, Br and I in granola: Development of an accurate analytical method using ICP-MS

Microwave-induced combustion (MIC) system for further Cl, Br, and I determination in granola by inductively coupled plasma mass spectrometry (ICP-MS) was proposed. A high sample mass of granola was pressed as pellets and inserted into the proposed MIC system. Water and NH4OH were evaluated as absorbing solutions. The accuracy was estimated by the analysis of two certified reference materials and also by spike recoveries. Using the optimized conditions (zirconium ball milling, 1 g of granola and 6 mL of 50 mmol L-1NH4OH), the agreement with the certified values ranged from 94 to 98% and recoveries higher than 95% were obtained. Low carbon concentration in digests (<25 mg L-1) was achieved, minimizing interferences by ICP-MS. Blanks were negligible and only diluted solutions were required. The concentration in samples ranged from 322 to 896, 0.618 to 0.980 and < 0.002 to 0.181 mu g g(-1) for Cl, Br and I, respectively.