National Marine Analytical Quality Assurance (AQA)
|Liquid nitrogen freezers
The National Marine Fisheries Service's Office of Protected Resources (NMFS/PR) and the National Institute of Standards and Technology (NIST) have established a program of Analytical Quality Assurance (AQA) as part of the Marine Mammal Health and Stranding Response Program (MMHSRP). The goal of the AQA is to improve the accuracy and comparability of results among laboratories conducting chemical analyses of marine mammal tissues. This program consists of:
- preparation, analysis, and distribution of marine mammal tissue analytical control materials;
- development of Standard Reference Materials (SRMs) specifically designed for use in the analysis of marine mammal tissues; and
- interlaboratory comparison exercises among laboratories analyzing marine mammal tissues.
The marine mammal AQA program is administered and coordinated by the NIST Chemical Science and Technology Laboratory (CSTL) in Gaithersburg, Maryland, through its Charleston, South Carolina, satellite facility. NIST Charleston is located in the newly-constructed Hollings Marine Laboratory at the South Carolina Marine Resources Center. The CSTL is nationally recognized as the definitive source of measurements, data, models, and reference standards in chemistry, biotechnology, and chemical engineering required to ensure U.S. technological leadership.
Analytical control materials are analyzed with regular samples and the results monitored to determine whether analytical procedures are in control. Contol materials developed for the MMHSRP are derived from fresh marine mammal tissues and are distributed to analysts as fresh-frozen homogenates (not freeze-dried). Both liver and blubber control materials are available with concentration values for a selected suite of trace elements for liver and PCB congeners and chlorinated pesticides for blubber.
SRMs have certified values for analytes and are used for validating analytical measurements and methods. SRM 1945 Organics in Whale Blubber was derived from blubber collected in 1991 from pilot whales stranded on Cape Cod, Massachusetts. This material was prepared in the same manner as control materials and is also distributed as a fresh-frozen homogenate. SRM 1945 has certified values for 27 PCB congeners and 15 chlorinated pesticides, and noncertified values for two additional PCB congeners, two addditional chlorinated pesticides, two polychlorinated naphthalene congeners, 12 brominated biphenyl ethers, and co-planar PCBs.
Interlaboratory comparison exercises are held annually. These exercises involve distributing an unknown sample, a control material, a NIST-traceable SRM, and a list of analytes to be measured to participating laboratories. The participants provide their results to NIST for evaluation. Comparability of data generated by the laboratories is evalutated using z- and p-scores following guidelines of the International Union of Pure and Applied Chemistry (IUPAC). Reports on the comparability evaluation are provided to the participants and meetings are held with the participants to discuss the results and ways to improve performance.
Dr. Teresa K. Rowles
1315 East-West Highway
Silver Spring, Maryland 20910
Dr. Paul R. Becker
219 Fort Johnson Road
Charleston, South Carolina 29412