Resumo

PEREZ GRANA, R.. Validation in-house and uncertainty estimation by recovery assays in fat gravimetric determination in canned foods of combat rations Spanish Army. Sanid. Mil. [online]. 2014, vol.70, n.2, pp.88-94. ISSN 1887-8571.  https://dx.doi.org/10.4321/S1887-85712014000200004.

Objectives: Validation in-house and estimation of the uncertainty through recovery assays in determination of fat in canned foods of combat rations by gravimetríc using the information generated in the validation process. Material and methods: Fat determination is carried out by gravimetríc, previously hydrolyzed with hydrochloric acid and extraction of fat with ether of petroleum 40-60^o, by means of Soxtec System Tecator. Representative matrix and concentrations of the future routine samples are analyzed (low, medium, high) by using a nested design of three factors. The trueness of the method is evaluated by estimating the proportional bias starting from the recovery assays. The uncertainty estimate is carried out by applying the propagation law of errors, that contains terms of uncertainty of precision, recovery and standard purity. The expanded uncertainty is obtained applying a coverage factor K=2 (confidence level of 95%). Results: The accuracy of the method can be considered good. Fat recoveries are obtained between 0,95 and 1,01 for the three concentration levels. The percentages of relative expanded uncertainty that are declared for each concentration level of fat in the samples of routines are the following ones: 0,50% (17,64%); 0,50-1,00% (13,09%); 1,00-16,55% (6,62%); 16,55-35,14% (6,00%); 35,14-50% (7,00%). Conclusions: The estimated uncertainty is carried out by using the information generated during the proportional bias estimate process, and it can be applied to the future routine samples analysis by this analytic method.

Palavras-chave : Uncertainty; Recovery; Fat; Canned foods; Combat rations.

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