Monolithic capillary microextraction on-line combined with ICP-MS for determining Ni, Cu and Cd in biological samples

Abstract

In this study, an ethylenediamine modified poly(glycidyl methacrylate-co-divinyl benzene) monolithic capillary column was prepared, and a novel method based on monolithic capillary microextraction on-line combined with inductively coupled plasma mass spectrometry (ICP-MS) was developed for determining Ni, Cu and Cd in biological samples. In order to improve the sample throughput, two polymer monolithic capillary columns were on-line parallelly combined with ICP-MS by employing a flow injection system. Various factors affecting the extraction efficiency, such as pH value, sample flow rate, sample volume, elution conditions and coexisting ions, were investigated in detail. Under the optimal conditions, the limits of detection were 14.7, 17.1 and 1.5 ng L⁻¹ for Ni, Cu and Cd, with the relative standard deviations (c = 50 ng L⁻¹, n = 7) of 3.0%, 3.9% and 3.5% for Ni, Cu and Cd, respectively. The proposed method was successfully applied to Ni, Cu and Cd analysis in human hair and urine samples with the recovery for the spiked samples in the 85–114% range.