Simultaneous separation and preconcentration of Cr(III), Cu(II), Cd(II) and Pb(II) from environmental samples prior to inductively coupled plasma optical emission spectrometric determination

Abstract

We have developed a new method of the separation, preconcentration, and determination of Cr(III), Cu(II), Cd(II) and Pb(II) ion in water samples. It is based on the use of activated carbon that was modified with rhodamine 6G to yield a solid-phase sorbent. The experimental conditions for adsorption were optimized. Cr(III), Cu(II), Cd(II) and Pb(II) can be quantitatively adsorbed at pH 4, and adsorbed Cr(III), Cu(II), Cd(II) and Pb(II) can be completely eluted with 1 M hydrochloric acid. The maximum adsorption capacity is 37.8, 47.8, 56.5 and 41.7 mg g −1 for Cr(III), Cu(II), Cd(II) and Pb(II). Cr(III), Cu(II), Cd(II) and Pb(II) ions were then determined by inductively coupled plasma optical emission spectrometry. The detection limit (3 σ) is under 0.35 ng mL −1, and the relative standard deviation is lower than 3.5% ( n = 11). Common potentially interfering ions do not interfere with the adsorption and determination of the analytes. The method displays selectivity, sensitivity and reproducibility, and was successfully applied to the determination of biological and water samples.