Extraction and Determination of Total Bromine, Iodine, and Their Species in Atmospheric Aerosol

Abstract

The bromine and iodine species in aerosol samples were extracted using ultrapure water ultrasonic method with different extraction time and using pressurizing decomposition with dilute ammonia. The efficiency of the extraction and the stability of bromine and iodine species were compared under different extraction conditions. The results showed that (1) the efficiency of extraction using pressurizing decomposition, which might destroy some unknown form of organic iodine, was relatively higher than those using ultrasonic method; (2) I− was unstable in added standard cellular blank filter during ultrasonic-assisted extraction for long time; and (3) the optimum condition was ultrapure water ultrasonic-assisted extraction for 5 min. Moreover, the suitability of glass microfiber filter (GF) and cellular filter (CF) during extraction for bromine and iodine species in aerosol was also compared, which indicated that GF is favorable for species analysis compared with CF under different kinds of extraction conditions. Based on the extraction results, HPLC-ICPMS approach was developed to analyze bromine and iodine species in atmospheric aerosol. The total iodine, bromine, and their species in the aerosol samples collected from Hefei were then determined accordingly. The levels of total bromine and iodine in Hefei aerosols were 883 and 231 pmol m−3, respectively. Br−was found to be dominant species with 68%, while BrO3− was undetectable. 70% of total iodine occurred as unidentified forms including soluble organic iodine and insoluble iodine.