A multinebulization technique for the determination of trace metals in a marine biota sample by on-line isotope dilution inductively coupled plasma mass spectrometry (OID-ICP-MS)

Abstract

A new concept of a nebulizer (i.e., multinebulizer) has been employed for trace element (e.g., Cd, Cu, Hg, Ni, Pb, and Zn) determination in marine biota samples (e.g., fish sample). To this end, an analytical methodology based on the combination of a multinebulizer with an isotope dilution (ID) calibration strategy and inductively coupled plasma mass spectrometry (ICP-MS) has been proposed. In this way, the on-line isotope dilution (OID) is accomplished by the simultaneous introduction of the liquid samples/standard and the isotopic reference solution (i.e., spike) into the plasma with an efficient mixing between them, which takes place at the inner cavity of the multinebulizer tip. The proposed OID-ICP-MS analytical methodology allows the fast determination of Cd, Cu, Hg, Ni, Pb and Zn in a biota sample certified reference material (CRM) (e.g., IAEA-476) with limits of detection of 0.006, 0.4, 0.09, 30, 0.2 and 4 ng g⁻¹, respectively, and recovery values ranging from 97 to 103%. The primary advantage offered by the proposed analytical methodology is that the time-consuming spiking step in the conventional ID analysis is avoided. This yields savings in both the total time and cost of the analysis per sample. Hence, it has been proved that OID-ICP-MS using a multinebulizer is a promising solution for the trace element analysis of samples with a high matrix content, which simplifies operation and significantly increases sample throughput and productivity.