Determination of total arsenic in seawater by hydride generation atomic fluorescence spectrometry

摘要

In this work, the determination of total As in seawater by hydride generation atomic fluorescence spectrometry was studied. The influence of the chemical, flow and instrumental parameters were investigated and optimized. The pre-reduction of As(V) to As(III) was performed using KI plus ascorbic acid in 3.5molL~(-1) HCl medium. No multiplicative interference was present and external aqueous calibration could be used. The limit of detection was 36ngL~(-1), while the repeatability was 2% (n=10), at a 500ngL~(-1) concentration level. The sample throughput was 15h~(-1) if triplicate measurements were made. The accuracy was assessed by the analysis of a seawater certified reference material and excellent agreement between the obtained and certified values was verified. The procedure was used for the analysis of seawater offshore samples collected at the Brazilian coast and results ranging from 860 to 1200ngL~(-1) were found.