Evaluation on measurement uncertainty of correction factors of fluconazole impurities determined by HPLC standard curve method

In this paper, the uncertainties of correction factors of fluconazole impurities determined by HPLC standard curve method were evaluated, and the main common factors affecting the accuracy of standard curve method were found, so as to improve the accuracy of the method.In this study, the corresponding fitting lines of fluconazole and its impurities A, B, C, D, F and I were established respectively, and the ratio of the slope of fitting lines of each impurity and its corresponding principal component was calculated as the correction factor of the impurity.Then on the basis of GUM method, the uncertainty of each impurity correction factor determined by standard curve method was evaluated according to the established uncertainty evaluation scheme of correction factor determination process.The correction factor and uncertainty of fluconazole impurities A, B, C, D, F and I were 1.068 ± 0.046, 0.102 ± 0.005, 0.0582 ± 0.0031, 1.382 ± 0.121, 0.802 ± 0.067 and 1.383 ± 0.119, respectively, and the coverage factor k was 2.Finally, the contribution rate of each uncertainty component was calculated.In the relative combined standard uncertainties u_rel(f) of fluconazole impurities A, B, C, D, F and I correction factors, the sum of contribution rate of slope uncertainty u_rel(K) of the linear equation of principal component and its impurity is more than 85%; in the slope uncertainties u_rel(K) of linear equation, the contribution rates of uncertainties of solution concentration in 8 of 12 data groups are more than 80%, and the contribution rates of uncertainties introduced by reference substance content in solution concentration are about 80%.It can be seen that the preparation of linear solution concentration is the most influential factor in the determination of impurity correction factor by standard curve method, followed by the linear fitting process.In the preparation process of linear solution concentration, the purity of reference substance is the most influential factor, followed by weighing and pipetting times.The conclusion can help the experimenters to better formulate experimental plans and ensure the accuracy of the results when doing similar work.