Large Aliquot Injection Approach in the Electrothermal AAS Determination of Arsenic in Environmental Water Samples

Abstract

Determination of As by direct electrothermal atomization atomic absorption spectrometry with a pyropytically-coated graphite furnace treated with W by a single drop treatment technique was reported. The treated PG furnace made it possible to introduce a 100 μ l aliquot of sample solution into the furnace with a high precision (RSD <4%). Use of a Pd-modifier made it possible to enhance the precision (RSD <3%) and the sensitivity. A good linearity (correlation factor >0.99) between integrated absorbance and injection volume was observed in the range 0–100 μ l. The calculated detection limit and characteristic mass (sensitivity) for integrated absorbance were 22 ng l−1 and 16 pg and for maximum absorbance were 45 ng l−1 and 13 pg for a 100 μ l injection with the Pd modifier at the optimum ashing temperature of 800 °C. An interference study for environmental matrices was also carried out. The recoveries of 2 and/or 4 μ g l−1 of As added to various water samples, such as snow, cloud, river and tap waters, were 97–104%.