High performance liquid chromatography hydride generation in situ trapping graphite furnace atomic absorption spectrometry: A new way of performing speciation analysis using GFAAS as detector

A new procedure for the speciation analysis of hydride forming elements using GFAAS as detector is proposed. The separation of the species is performed by HPLC and the eluent flow is merged with HCl and NaBH₄ solutions moved by peristaltic pumps controlled by a flow injection apparatus. As the species emerges from the column, its respective hydride is formed and carried through the autosampler capillary to an Ir treated graphite tube pre-heated at 300 °C, where it is trapped. After the hydride collection, the autosampler arm is moved from the tube and atomization takes place. The sequence is repeated for the next emerging species. The feasibility of the system was evaluated for the speciation of As (III) and As (V) in waste water samples. The retention times were previously determined using a more concentrated mixed analytical solution and a quartz tube as atomizer. The analytical curves obtained by the proposed procedure showed similar slopes for both species as well as coefficient of regression better than 0.99. Limits of detection were 0.2 ng/mL for both species, 50 times better then the same assembly using a quartz tube atomizer. In the analysis of certified reference materials the sum of the As (III) and As (V) species concentrations were in close agreement with the arsenic concentration certified for total arsenic.