NIST and the Centers for Disease Control and Prevention (CDC) are collaborating to develop seven new SRMs to meet the expanding needs for the measurement of organic contaminants in human fluids: two serum -- one natural level (non-fortified) and one fortified, two milk -- one natural level (non-fortified) and one fortified, and three urine -- one natural level collected from non-smokers, one natural level collected from smokers, and one fortified level collected from non-smokers. Results from measurements made at NIST and CDC as well as data from interlaboratory studies will be used for value assignment of these SRMs.
The development of SRMs to support measurements for contaminants in human fluids will expand quality assurance capabilities to important species critical to human health. These SRMs will be used by the monitoring laboratories to validate methods and control materials for specific analyses. We are developing and characterizing several natural-matrix SRMs for organic contaminants: human serum, human milk, and human urine reference materials. We employ results from multiple analytical methods at NIST and data provided collaborating laboratories to assign values to chemical composition. We are also developing robust methods of analysis for use by the biomonitoring community.
Two human serum SRMs and two human milk SRMs have been value assigned for a wide range of organic contaminants based on methods performed at NIST, CDC, and four additional collaborating laboratories.
NIST and CDC are collaborating on the development of seven SRMs that will be useful to the biomonitoring community. These include SRM 1953 Organic Contaminants in Non-Fortified Human Milk, SRM 1954 Organic Contaminants in Fortified Human Milk, SRM 1957 Organic Contaminants in Non-Fortified Human Serum, SRM 1958 Organic Contaminants in Fortified Human Serum, SRM 3672 Organic Contaminants in Smokers' Urine, SRM 3673 Organic Contaminants in Non-fortified Non-smokers' Urine, and SRM 3674 Organic Contaminants in Fortified Smokers' Urine. The fortified serum and milk samples were spiked with a solution containing 172 selected contaminants. The fortified samples contain a concentration of those contaminants at levels five to ten times higher than the median concentrations found in the U.S. population. Methods have been developed at NIST and at CDC for these measurements in the human serum and human milk materials, and the results from the independent methods were combined to provide certified concentration values for contaminants in those materials. The urine samples are now being characterized by NIST and CDC.