Preconcentration and determination of metal ions using fluorescein-modified silica gel and inductively coupled plasma-optical emission spectrometry

Abstract

A new fluorescein modified silica gel was utilized for solid-phase extraction for the simultaneous and selective preconcentrations of Ba2+, Cd2+, Co2+, Cu2+, Mn2+, Ni2+, Pb2+, and Sr2+ prior todetermination by inductively coupled plasma-optical emission spectrometry. The sorbent was characterized using X-ray diffraction and scanning electron microscopy. The optimum conditions were 25.0 mL of sample at pH 5.0 and a 3.0 mL min(-1) flow rate. The ions were desorbed with 3.0 mL of 0.5 mol L-1 HNO3 at 3.0 mL min(-1). The relative standard deviations were below 5%, and the limits of detection were between 11.5 and 152.0 ng L-1. The preconcentration factor was 8.3 for Sr2+ and 333.3 for Ba (2+), Cd2+, Co2+, Cu2+, Mn2+,Ni2+, and Pb2+. The uptake capacity of the sorbent was between 0.29 and 1.25 mg g(-1). The accuracy was assessed by analyzing water certified reference materials. The recoveries for the standard reference materials were between 92.5 and 102.9% except for Sr2+. The method was used for the analysis of natural water samples.