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Objiective: In presence of measurement uncertainty evaluation, the detection methods, with water-sodium chloride pretreatment, for health food was evaluated. Methods: A mathematical model was established to analysis of uncertainty sources. Then the individual components of uncertainty were evaluated. Finally, the combined uncertainty and extended uncertainty were calculated. Results: The uncertainty caused by several factors, including the fitting of the standard curve, the preparation of solution and standard, the repeatability of measurement, and the weigh of sample.The contents of mevastatin, lovastatin and simvastatin were 0.099 2, 0.101 0, 0.099 5 mg/kg in health foods, respectively. The relative combined standard uncertainties were about 0.003 2, 0.005 6, 0.005 1 mg/kg, k=2. Conclusion: Water-sodium chloride pretreatmen can reduce the interference of matrix and the uncertainty introduced by repeatability. |
