Environmental monitoring of total mercury content in different marine compartments after cold vapor generation and inductively coupled plasma mass spectrometry determination

Analytical procedure for environmental and seafood safety monitoring of total mercury content, based on the external calibration methodology and cold vapor generation inductively coupled plasma mass spectrometry determination, was validated according to the requirements of international guidelines and standards. Marine samples with varying levels of mercury: marine biota, marine sediment and costal sea waters were used in this study. A full validation approach in line with the ISO/IEC 17025 and Eurachem guidelines was followed. With this in mind, blanks, selectivity, working range (1.2 ng kg −1 to 240 ng kg −1 ), linearity (0.9991), recovery (97 % to 103 %), repeatability (< 2.5 %), intermediate precision (< 3.5 %), limit of detection (0.72 ng kg −1 ) and limit of quantification (1.10 ng kg −1 ) were systematically assessed. The uncertainty of measurement results was estimated according to the recommendations of the Guide to the expression of Uncertainty in Measurement. The relative expanded uncertainty was in the range between 14.2 % and 15.8 % ( k = 2) for marine biota and sediment samples, respectively, and rise up to 32.8 % ( k = 2) on the total mercury mass fraction in costal seawater at the level of 5 ng kg −1 . The major contribution to the combined uncertainty was found to come from the uncertainty associated with the correction for recovery and procedural blanks. The performance of validated procedure was demonstrated by its application to the low-level Hg content seawater samples, received in the frame of Proficiency Testing Scheme, conducted by the Quality Assurance of Information in Marine Environment Monitoring in Europe. The result for total mercury content in marine sediment IAEA-475 was used as the contribution of the IAEA in the characterization campaign of the IAEA-475 candidate certified reference material. The demonstrated SI traceability of obtained results is a prerequisite for their further comparisons with monitoring data obtained in different place and time.