Photochemical vapor generation of iodine for detection by ICP-MS

Abstract

A systematic evaluation of UV-photochemical generation of volatile iodine species for detection by ICP-MS is described. Several UV-based systems were studied, the most advantageous design being a modified cyclonic spray chamber fitted with a 6 W mercury pen lamp supplying 1 ml min−1 sample to a glass concentric nebulizer. Optimal conditions utilized a 5% v/v solution of acetic acid as the generation medium. The presence of the UV field enhanced signal intensity approximately 40-fold, providing a (blank limited) limit of detection of 0.7 pg ml−1127I+ and a precision of replicate measurement of 4% RSD at 10 ng ml−1 iodine. Using DRC technology and O2 as the reaction gas, suppression of 129Xe+ provided an estimated LOD of 6 fg ml −1129I+ in aqueous samples.