Resumo de eventos cient??ficos
Preparation of biological reference materials at LAN ??? IPEN ??? CNEN/SP
Autor
MOREIRA, E.G.
MAIHARA, V.A.
CASTRO, L.
VASCONCELLOS, M.B.A.
60 YEARS OF IEA-R1: INTERNATIONAL WORKSHOP ON UTILIZATION OF RESEARCH REACTORS
Resumen
Three biological reference materials were prepared to be used in interlaboratory
programs and/or proficiency tests, as well as, for calibration of analytical instruments
and validation of analytical methods for environmental trace elements: A Perna perna
mussel reference material was produced and certified by means of an interlaboratory
comparison. The material was designed as a quality assurance tool for element
biomonitoring studies along the Brazilian seashore. For the preparation of the Brazilian
mussel reference material, 164kg of Perna perna (Linnaeus, 1758) mussels were
purchased from a single producer, from Cocanha Beach in Caraguatatuba City, S??o
Paulo State North Shore where mussels are cultivated by the longline system. After
cleaning, freeze-drying and homogenization, the mussel samples were packed in
171 bottles and, the material was irradiated with a gamma ray dose of 5 kGy to
enhance its stability. The certified mass fraction values and associated expanded
uncertainties were obtained for Al, As, Ca, Cd, Cl, Co, Cu, Fe, K, Mg, Mn, Na, Ni,
Se, Th and Zn at the certification campaign. A fish tissue reference material was
produced in the context of an International Atomic Energy Agency (IAEA) project
aiming analytical quality improvement for laboratories of the Latin American and
Caribbean region. Whitemouth croake (Micropogonias furnieri), known as corvina,
was the chosen species due to its low cost and high consumption in Latin America
countries. For preparation, about 300kg of fish was collected and only the edible
parts were used. After adequate processing, the fish material was bottled in 534
bottles with approximately 25g each. The reference values and associated expanded
uncertainty (k = 2) were established for As, Cd, Cu, Fe, K, Mn, Na, Se and Zn;
Finally, a bovine kidney reference material to be used in the quality control of meat
products was prepared using 35 kg of fresh bovine kidney from cattle reared under
controlled feeding conditions. The preparation resulted in a final batch of 175 flasks. It was possible to assign values to 20 elements with their respective uncertainties,
being 9 certified values (As, Cu, Fe, K, Mg, Mn, Na, Se and Zn), 10 indicative values
(Br, Ca, Cd, Cl, Co, Cs, Hf, Mo, P and Rb) and 1 as additional information (Hg).
All the three reference material production projects took advantage of the unique
metrological properties of Instrumental Activation Analysis (INAA) not only in the
certification process but also in the homogeneity and stability assessment following
ISO Guide 30 series recommendations.