On-site determination of heavy metals in drinking water by disk solid-phase extraction/handheld X-ray florescence analysis

Abstract

A rapid and simple method using handheld X-ray fluorescence analysis after disk solid-phase extraction was developed for the on-site determination of Mn, Fe, Cu, Zn, Cd, Hg and Pb in drinking water. A 50 mL aqueous sample was adjusted to pH 5 with acetate buffer, and then passed through an iminodiacetate chelating disk to preconcentrate heavy metals. The chelating disk was coated with adhesive cellophane tape, and then dried at 100 °C for 60 s. The disk was examined by handheld X-ray fluorescence spectrometer. The detection limits were 6.6 µg L-1 for Mn, 9.4 µg L-1 for Fe, 4.0 µg L-1 for Cu, 3.6 µg L-1 for Zn, 7.6 µg L-1 for Cd, 4.4 µg L-1 for Hg and 3.2 µg L-1 for Pb. Spike tests comprised of 40 µg L-1 and 100 µg L-1 of heavy metals in natural mineral water and well water samples demonstrated that quantitative recoveries were achieved (89.0-110 %). Since the proposed method did not require an electronic power supply and toxic reagents in an analytical step, it is suitable for on-site determination of heavy metals in water.