Abstract: An analytical method using isotope dilution cold vapor inductively coupled plasma mass spectrometry (ID-CV-ICPMS) was developed for the determination of total mercury in the eggs of seabirds. Components including error magnification, verification of method accuracy and assignment of analytical uncertainty are presented in the context of collecting mercury data for single sample aliquots. Forty-one egg samples collected from common murre (Uria aalge) colonies on Little Diomede and Saint George Islands in the Bering Sea and East Amatuli and Saint Lazaria Islands in the Gulf of Alaska yielded mercury mass fraction values ranging from approximately 0.010 µg g-1 to 0.360 µg g-1. Relative expanded uncertainties for the individual determinations ranged from 1.2% to 4.4%. A one-way analysis of variance including pairwise comparisons across the colonies showed that mercury levels in eggs collected from the Gulf of Alaska colonies were significantly higher than their counterparts in the Bering Sea. Mercury data from each colony were normally distributed, suggesting a ubiquitous regional deposition of mercury and corresponding incorporation into local foodwebs.

Abstract: An isotope dilution cold vapor inductively coupled plasma mass spectrometry (ID-CV-ICPMS) method featuring gaseous introduction of mercury via tin chloride reduction has been developed and applied to the quantification and certification of mercury in various NIST standard reference materials: SRM 966 Toxic Metals in Bovine Blood (30 ng mL-1); SRM 1641d Mercury in Water (1.6 µg mL-1); and SRM 1946 Lake Superior Fish Tissue (436 ng g-1). Complementary mercury data were generated for SRMs and NIST quality control standards using cold vapor atomic absorption spectroscopy (CVAAS). Certification results for the determination of mercury in SRM 1641d using two independent methods (ID-CV-ICPMS and CVAAS) showed a degree of agreement of 0.3% between the methods. Gaseous introduction of mercury into the ICPMS resulted in a single isotope sensitivity of 2 x 10(6) counts s-1 ng-1 g for Hg-201 and significantly reduced the memory and washout effects traditionally encountered in solution nebulization ICPMS. Figures of merit for isotope ratio accuracy and precision were evaluated at dwell times of 10, 20, 40, 80, and 160 ms using SRM 3133 Mercury Spectrometric Solution. The optimum dwell time of 80 ms yielded a measured Hg-201/Hg-202 isotope ratio within 0.13% of the theoretical natural value and a measurement precision of 0.34%, on the basis of three replicate injections of SRM 3133.