Determination of As, Sb, and Se in acid extracts from coal, fly ash, and slag samples by hydride generation ETAAS

Methods for the determination of As, Sb, and Se in coal, fly ash, and slag samples involving microwave acid extraction, hydride generation, trapping, and atomization of the hydrides generated in a graphite furnace have been d eveloped. Two microwave acid extraction procedures using aqua regia and aqu a regia + hydrofluoric acid were compared. Hydrides were generated from hyd rochloric acid medium using sodium tetrahydroborate. Zr-treated graphite tu bes were used for the in situ pre-concentration of hydrides. generated. A c ollection time of 30 s and trapping temperatures of 800, 600, and 500 degre esC were used for As, Sb, and Se, respectively. The atomization temperature s used were 2100, 1600,. and 2300 degreesC, respectively. Characteristic ma sses of 40, 17, and 90 pg for As, Sb, and Se, respectively,, were achieved. The accuracy was studied using NIST-1633b (coal) and NIST-1632b (coal fly ash) reference materials. The methods were applied to several coal, coke, c oal fly ash, and slag samples.