Linearity solutions of all the impurities were prepared at sevenconcentration levels ranging from the LOQ to 150% of the specificationlevel (LOD—0.75 g/mL). The peak area of the analyte versusconcentration was analyzed by least squares linear regression(Table 1). The calculated parameters of the calibration curves indicatedsatisfactory linearity. The correction response factor (CRF)was calculated from the ratio of the slope of principal componentsand impurities by linear regression. The results indicate that the response factors of all impurities are within 0.89–3.23 (Table 1).