Extraction and Determination of Total Bromine,Iodine and Species in Atmospheric Aerosol
The species of bromine and iodine in aerosol samples were extracted using ultra-pure water-ultrasonic method with different time in-length and pressurizing decomposition with dilute ammonia,respectively.The efficiency of extraction and the stability of bromine and iodine species were compared under different extraction conditions.Results showed that(1) the efficiency of extraction using pressurizing decomposition,which might destroy some unknown form of organic iodine,was relatively higher than the one by ultrasonic method;(2) I-was unstable in added standard cellular blank filter during ultrasonic assisted extraction for long time;(3) The optimum condition was ultra-pure 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 than CF under different kinds of extraction conditions.Based upon the extraction results,HPLC-ICP-MS approach was developed to analyze bromine and iodine species in atmospheric aerosol.The total iodine,bromine and species in the aerosol samples collected in Hefei were then determined accordingly.The levels of total bromine and iodine in Hefei aerosols were 883 and 231 pmol/m3,respectively.Br-was found to be dominant species with 68%,while BrO-_3 was undetectable.70% of total iodine occurred as unidentified forms including soluble organic iodine and insoluble iodine.