Determination of trace metals in seawater by on-line column preconcentration inductively coupled plasma mass spectrometry using metal alkoxide glass immobilized 8-quinolinol

Abstract

Metal alkoxide glass immobilized 8-quinolinole (MAF-8HQ) was synthesized from the solutions for the resin for analysis of ultra trace level iron determination in seawater by Nakayama and Obata. Since the blank values of trace metals in the resin are very low, the resin was applied for the determination of trace metals in seawater. A home made column of MAF-8HQ was used to separate and concentrate trace metals (V, Mn, Co, Ni, Cu, Zn, Mo, Cd, Pb and U) from seawater. An automated low pressure flow analysis method with on-line column preconcentration/inductively coupled plasma mass spectrometry (ICP-MS) was used for the determination of trace metals in seawater. Sample solutions (adjusted to pH 5.5) were passed through the column. After washing the column with water, the adsorbed metals were subsequently eluted into the plasma with 0.7 M nitric acid. Detection limits (DLs) of the trace metals in the artificial seawater were 0.008 ng ml −1 for V, 0.004 ng ml −1 for Mn, 0.004 ng ml −1 for Co, 0.014 ng ml −1 for Ni, 0.014 ng ml −1 for Cu, 0.050 ng ml −1 for Zn, 0.002 ng ml −1 for Mo, 0.003 ng ml −1 for Cd, 0.017 ng ml −1 for Pb and 0.001 ng ml −1 for U, respectively, as the concentrations of analyte metals corresponding to three times (3 σ) the standard deviation of blank signal intensities by 10 replicate measurements. By using 120 s of sample loading times, 40–66-fold enrichment factors were obtained for V, Co, Cu, Zn, Cd, Pb and U. One sample can be processed in 7 ml and 7 min. The proposed method was verified by the analysis of trace metals in the two certified reference materials (CRMs) of seawater CASS-4 and NASS-5.