Tin determination in marine sediment, soil, coaly fly ash and coal slurried samples by hydride generation-electrothermal atomic absorption spectrometry

摘要

Different procedures of tin hydride generation from aqueous and acidified slurries of marine sediment, soil, coal fly ash and coal samples, coupled to electrothermal atomic absorption spectrometry were optimized by suing factorial designs. A batch mode generation system and Ir-treated graphite tubes were used of the hydride generation and atomization, respectively. Eight variables, affecting the hydride generation and hydride transport efficiency) trapping temperature and trapping time) and the atomization efficiency (atomization temperature) were studied and optimized. In addition, acid pre-treatment procedures assisted by ultrasonic energy were used for soil and coal matrices, to obtain acidified slurries and acid lactates. The involved variables were hydrochloric and nitric acid concentration, exposure time to ultrasound, particle size and leaching solution volume. Adequate accuracy (41.5 +- 0.8 and 1.4 +- 0.2 mg kg~(-1), for PACS-1 (sediment marine) and NIST-1633b (coal fly ash), respectively) were obtained by using aqueous slurry reference materials. In addition, values of 6.2 +- 0.6 and 1.2 +- 0.1 mg kg~(-1) were assessed by analysis GBW-07401 (soil) and NIST-1632c (coal) certified reference materials.