Feasibility of using Total Reflection X-ray Fluorescence Spectrometry for Drinking Water Analysis

The quantitative elemental measurements in drinking water are a very important task since Brazilian legislation establishes the threshold limit value for each element. Besides Atomic Absorption Spectrometry (AAS) and Inductively Coupled Plasma Optical Emission Spectrometry (ICP OES) have been routinely used for this purpose, Total Reflection X-ray Fluorescence spectrometry (TXRF) seems to be a very interesting alternative. It provides a fast and easy sample preparation, low analytical operation and maintenance costs. This study shows the feasibility of using TXRF for monitoring simultaneously the presence of arsenic, barium, lead, copper, chromium, nickel, selenium, uranium, iron, manganese and zinc in drinking water samples. All measurements were performed using TXRF spectrometer, equipped with an air cooled low power X-ray tube (Mo target). For internal calibration, 950 mu L of sample was mixed with 50 mu L of a standard solution containing 10 mg L--(1) of gallium. For most of the elements, the direct quantification by TXRF using Ga as internal standard could be used. For the Cr, Ni and U measurements, analytical calibration curves have to be adopted. The limits of detection for proposed method are appropriate for all elements investigated. In addition, the method showed good precision and accuracy and seems to be a very interesting alternative to be used in the routine analysis involving elemental measurement in drinking water samples analysis.