reference materials from the National Research Council of Canada, lobster
hepatopancreas (TORT-2) and fish protein (DORM-3). Standard solutions
ofMMHgwere calibrated using a Hg(II) solution traceable to the
U.S. National Institute of Standards and Technology (NIST). All measurements
ofMMHg in DORM-3 (n=27 samples) and all but one measurement
of TORT-2 (n = 30) were within the certified ranges. The mean
(±1SD) measured concentration of MMHg in DORM-3 was 329 ±
21 ng/g dry wt. (certified range = 299–411 ng/g) and that in TORT-2
was 150 ± 7 ng/g (certified range = 139–165 ng/g). Imprecision of
MMHg analyses between procedural duplicates of soup averaged 7.7
relative percent difference (n = 7). The estimated detection limit for
MMHg was ~0.01 ng/mL in soup and 0.02 ng/g for a 0.1-g sample of dried fin.