Fish otolith reference material for quality assurance of chemical analyses

Abstract

A certified reference material (CRM) for major, minor and trace element analysis was prepared from sagittal otolith of red emperor ( Lutjanus sebae ) at National Institute for Environmental Studies (NIES), Japan in collaboration with Western Australian Marine Research Laboratories (WAMRL), Australia. Otoliths (1.4 kg) were cleaned, pulverized, sieved to pass a 105-μm screen and homogenized, and 375 vials, each containing 3 g, were prepared. Certified value was determined for Na, Mg, K, Ca, Sr and Ba through a collaboration involving NIES and five other laboratories. The certified value (mean of the means reported from the collaborating laboratories plus or minus the 95% confidence interval) were 97.0±4.2 μmol/g (0.223±0.010%) for Na, 0.88±0.06 μmol/g (21±1 μg/g) for Mg, 7.21±0.20 μmol/g (282±8 μg/g) for K, 9.69±0.11 mmol/g (38.8±0.5%) for Ca, 26.9±0.5 μmol/g (0.236±0.005%) for Sr and 21.1±0.6 nmol/g (2.89±0.09 μg/g) for Ba. Reference values were given for Cu [12 nmol/g (0.74 μg/g)], Zn [7.2 nmol/g (0.47 μg/g)], Cd [0.025 nmol/g (0.0028 μg/g)] and Pb [0.11 nmol/g (0.023 μg/g)] based on definitive analyses at NIES. This CRM will be of practical value for the quality assurance of solution-based elemental analysis of fish otoliths and other marine aragonites .