Two tuna fish reference materials containing methyl mercury were prepared. Homogeneity and stability studies and analytical work were performed for the certification of the contents of total and methyl mercury. The methods used to certify the mass fractions of total mercury (2.85 ug/g in CRM 463 and 5.24 ug/g in CRM 464, on a mass of dry matter basis) and methyl mercury (3.04 ug/g in CRM 463 and 5.50 ug/g in CRM 464, as MeHg cations on a dry mass basis) were established.
Mercury occurs in the environment in various forms e.g. elementary mercury (Hg), inorganic mercury and methyl mercury (MeHg). Elementary mercury is mainly present in the air; inorganic mercury in water; and methyl mercury occurs predominantly in the contaminated food chain (e.g. shell-fish). Methyl mercury compounds are of paramount importance: their toxicity and the risk of humain exposure are high. Because of its toxicity and abundance in the food chain, the limits of exposure to MeHg are at least 5 times less than the exposure to other Hg-compounds. The objective of the project is to develop through collaborative work of a number of experienced laboratories a methodology for accurate determination of MeHg in food. It is envisaged that in a second phase reference materials will be prepared e.g. fish and shell-fish.
Third intercomparison concluded in 1991. Certification campaign started in 1992 [mercury and methyl-mercury in tuna fish: candidate CRMs 463 (low content) and 464 (high content)].
Funding SchemeCSC - Cost-sharing contracts
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