Off-line preconcentration and inductively coupled plasma sector field mass spectrometry simultaneous determination of Cd, Co, Cu, Mn, Ni, Pb and Zn mass fractions in seawater: Procedure validation

Abstract Despite the ongoing reduction of emissions of contaminants into the environment, the ocean still represents the most anthropogenically impacted ecosystem worldwide. Sound strategies for marine chemical monitoring call for measurement systems capable of producing comparable analytical results with demonstrated quality. An analytical procedure for simultaneous measurements of the Cd, Co, Cu, Pb, Mn, Ni, Pb and Zn mass fractionsin open ocean waters was validated. Procedure validation, including systematic combined uncertainty estimations on measurement results, and the traceability of data are described and explained. Off-line analytes pre-concentration and matrix separation was performed with the commercially available automated seaFAST-pico™ system, followed by inductively coupled plasma sector field mass spectrometry (ICP-SFMS) mass fractionsdetermination. The validation approach applied in the present study is in line with the requirements of ISO/IEC 17025standard and Eurachem guidelines. Selectivity, working range, linearity, recovery (from 93% to 100%, obtained using the NASS-6 CRM from NRC, Canada), repeatability (1.5–3%), intermediate precision (2–%), limits of detection (0.00006–0.004 μg kg −1 ) were systematically assessed. The relative expanded uncertainties obtained were at range from 7.0% to 14.0% (k = 2). Excellent results were obtained when applying this procedure to the NASS-7 CRM from NRC, Canada. The potential of this analytical procedure was also tested on open seawater samples from different regions of the world. The validated procedure was applied for the characterisation of the ERM®-CA403 candidate certified reference materialand obtained results submitted as the IAEA contribution to this certification.