IC-ICP-MS Determination of Residual Amounts of Bromate in Flour and Flour Products

Sample of flour or its products was dispersed with water (for fatty sample petroleum ether was added together with the water) and extracted ultrasonically.The mixture was centrifuged and a definite aliquot was taken for purification by passing through the On-Guard Ⅱ column to remove part of organic impuritres.Eluate from the column was used for IC-ICP-MS analysis to determined content of bromate.To achieve to the best sensitivity of the MS detection,high power parameters were adopted.The isotope 79Br was selected as the analytical isotope and the main MS interference of multi-atom was eliminated by separation on the chromatographic column.Nitric acid and aqueous ammonia were used as the mobile phase.Linearity range of the working curve was in the range within 100 μg·L-1 of BrO-3 ion.Detection limit (3σ/b) of the method found was 0.6 μg·L-1.The proposed method was used to analyze 2 kinds of samples for their bromate contents,giving value of average recovery of 97% and values of RSD′s (n=8) in the range of 3.3%-8.3%.