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 µg g^-1 for Cl, Br and I, respectively.