Trace element analysis of bovine liver: interlaboratory survey in Australia and New Zealand.

An interlaboratory survey of the determination of trace elements in bovine liver was undertaken. Thirty-three laboratories from Australia and 15 from New Zealand returned results. Moisture determination results were variable despite the use of a recommended drying procedure. For the 10 trace elements determined, the mean values (microgram/g) with their interlaboratory coefficients of variation (CV) were: cadmium, 1.2 (42.5%); cobalt, 0.21 (9.5%); copper, 110 (6.0%); iron, 276 (11.0%); lead, 0.6 (48.9%); manganese, 8.6 (13.9%); mercury, 0.03 (30.0%); molybdenum, 2.5 (45.6%); selenium, 1.0 (17.5%); zinc, 219 (8.2%). The intralaboratory CV for determining each of these elements was less than 9% except for the lead CV which was 20.2%. Results for the determination of sodium, potassium, calcium, and magnesium were also reported. The survey shows that while the use of a standard reference material can improve the performance of laboratories in trace element analysis, it may also introduce analytical bias.