Analytical Sciences

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

Shoji IMAI,*¹Ž€Û¬enichiro FUJIKAWA,*¹ Akira YONETANI,*² Nobuaki OGAWA,*³ and Yoichi KIKUCHI*⁴

*1 Department of Chemistry, Faculty of Integrated Arts and Sciences, The University of Tokushima,Tokushima 770-8502, Japan
*2 Hitachi Instruments Engineering Co. Ltd., Hitachinaka, Ibaraki 312-8504, Japan
*3 Department of Materials-process Engineering & Applied Chemistry for Environment, Faculty of Engineering and Resource Science, Akita University, Akita 010-8502, Japan
*4 Department of Chemistry, Faculty of Education, Iwate University, Morioka 020-8550, Japan

Determination of As by direct electrothermal atomization atomic absorption spectrometry with a pyropytically-coatedgraphite furnace treated with W by a single drop treatment technique was reported. The treated PG furnace made itpossible to introduce a 100 ml aliquot of sample solution into the furnace with a high precision (RSD < 4%). Use of a Pd-modifiermade 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 ml. The calculateddetection limit and characteristic mass (sensitivity) for integrated absorbance were 22 ng l^-1 and 16 pg and for maximumabsorbance were 45 ng l^-1 and 13 pg for a 100 ml injection with the Pd modifier at the optimum ashing temperature of 800¡Ã. An interference study for environmental matrices was also carried out. The recoveries of 2 and/or 4 mg l^-1 of Asadded to various water samples, such as snow, cloud, river and tap waters, were 97 - 104%.

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