SRM 955c - Toxic Elements in Caprine Blood /Level 3
An alternative replacement material for SRM 966 is SRM 955c Toxic Elements in Caprine Blood, which was issued as Lead in Caprine Blood by NIST in 2007 with support from the CDC. SRM 955c is heavily relied upon for quality assurance of clinical blood Pb measurements, and is certified for Pb at four concentration levels: a base level and three progressively elevated levels. When SRM 955c was produced at the Wadsworth Center, New York State Department of Health (NYDOH), it was also spiked with As, Cd, iHg, MeHg, and EtHg. EtHg is a concern because it is a metabolite of Thimersol which has been used as a preservative in vaccines and is being studied in the proposed link between autism and Hg exposure. The toxicity of Hg is highly dependent on the chemical form, necessitating measurement of the specific Hg species. As, Cd, and THg are typically analyzed together as a “heavy metal screen” for diagnosis of acute poisoning utilizing a multi-element analysis method, inductively coupled plasma mass spectrometry (ICP-MS). Half of all blood analyses in the U.S. are performed using ICP-MS. SRM 955c will serve multiple measurement communities and is the first available whole blood CRM with EtHg and As values.
keywords: biological materials , body fluids , blood , trace elements , heavy metals , mercury speciation , speciation analysis , organometallics