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|Título: ||Measurement uncertainty of food carotenoid determination|
|Autor: ||Dias, M. Graça|
Camões, M. Filomena
Oliveira, Luísa M.
Composição de Alimentos
|Issue Date: ||2012|
|Citação: ||Accred Qual Assur. 2012;17:183-189|
|Resumo: ||For consistent interpretation of an analytical
method result it is necessary to evaluate the confidence that
can be placed in it, in the form of a measurement uncertainty
estimate. The Guide to the expression of Uncertainty
in Measurement issued by ISO establishes rules for
evaluating and expressing uncertainty. Carotenoid determination
in food is a complex analytical process
involving several mass transfer steps (extraction, evaporation,
saponification, etc.), making difficult the application of
these guidelines. The ISO guide was interpreted for analytical
chemistry by EURACHEM, which includes the
possibility of using intra- and interlaboratory information.
Measurement uncertainty was estimated based on laboratory
validation data, including precision and method
performance studies, and also, based on laboratory participation
in proficiency tests. These methods of uncertainty
estimation were applied to analytical results of different
food matrices of fruits and vegetables. Measurement
uncertainty of food carotenoid determination was 10–30%
of the composition value in the great majority of cases.
Higher values were found for measurements near instrumental
quantification limits (e.g. 75% for b-cryptoxanthin,
and 99% for lutein, in pear) or when sample chromatograms
presented interferences with the analyte peak (e.g. 44% for
a-carotene in orange). Lower relative expanded measurement
uncertainty values (3–13%) were obtained for food
matrices/analytes not requiring the saponification step.
Based on these results, the saponification step should be
avoided if food carotenoids are not present in the ester form.
Food carotenoid content should be expressed taking into
account the measurement uncertainty; therefore the maximum
number of significant figures of a result should be 2.|
|Arbitragem científica: ||yes|
|Versão do Editor: ||http://www.springerlink.com/content/m9w3744701053h51/?MUD=MP|
|Appears in Collections:||DAN - Artigos em revistas internacionais|
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