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EVALUATION OF A MATRIX INTERFERENCE IN GROUND WATER ARSENIC MEASUREMENT BY ICP-OES
Citation:
XU, N. AND R. G. FORD. EVALUATION OF A MATRIX INTERFERENCE IN GROUND WATER ARSENIC MEASUREMENT BY ICP-OES. Presented at 2005 American Chemical Society Meeting & Exposition, Washington, DC, August 28 - September 01, 2005.
Impact/Purpose:
To inform the public.
Description:
Arsenic enters ground water systems by either the weathering of naturally occurring subsurface materials or human activities such as mining and pesticide manufacturing. The current EPA drinking water limit for arsenic is set at 50 ug/L, with the reduction to 10 ug/L in 2006. Therefore, it is necessary to examine and update our current analytical technologies so that they will be in compliance with the Agency's requirements. The major analytical approach accepted for elemental determination in ground water is ICP-OES. This method has been adopted by most of the laboratories because of its capability of detecting multielements at low concentrations simultaneously. However, one has to be careful about possible matrix interferences during the utilization of this technique. Recently, a false positive reading for arsenic in some ground water samples by ICP-OES has been observed. Statistical analysis on sample characteristics has been conducted to suggest possible sources that contribute to this artifact. Different sample treatment methods were also studied to eliminate the problem.