2%, which confirms the good precision of the method. The %RSD new post values for BHT are presented in Table 2. Table 2 Repeatability and intermediate precision test results Limits of detection and quantification The LOD and LOQ for BHT were determined at a signal-to-noise ratio of 3:1 and 10:1, respectively, by injecting a series of diluted solutions with known concentrations. Precision study was also carried out at the LOQ level by injecting six individual preparations of BHT and calculated the %RSD of the area. The determined limit of detection, limit of quantification and precision at LOQ values for BHT are reported in Table 3. Table 3 Linearity and LOD-LOQ data Linearity Linearity test solutions were prepared by diluting the stock solutions to the required concentrations by covering the range from 0.

0039 to 0.64 ��g/mL of BHT [Table 4]. The solutions were prepared at six concentration levels from LOQ to 200% of specification level (LOQ, 25%. 50%, 100%, 150% and 200%). Calibration curves were plotted between the responses of peak versus analyte concentrations [Figure 5]. The correlation coefficient obtained was greater than 0.999 and % bias at 100% level are within �� 2%. The above result shows that an excellent correlation existed between peak area and concentration of BHT. The coefficient correlation, slope and y-intercept of the calibration curve and bias at 100% response are summarized in Table 3. Table 4 Linearity study concentration of BHT and peak area Figure 5 Linearity graph Accuracy Accuracy of the method BHT were evaluated in triplicate using six concentration levels LOQ (0.

0039), 0.08, 0.16, 0.32, 0.48 and 0.64 ��g/mL The percentage recoveries for BHT were calculated and varied from 98.8 to 104.8. The recovery values are presented in Table 5. Table 5 Recovery data Robustness To determine the robustness of the developed method, experimental conditions were deliberately altered and system suitability (SST) parameters for BHT standard were recorded. The variables Carfilzomib evaluated in the study were composition of the mobile phase, column temperature and flow rate. The flow rate of the mobile phase was 0.8 mL/min. To study the effect of flow rate on the SST, flow was changed from 0.6 to 1.0 mL/min. The effect of composition of mobile was studied at 90% and 110% of the method organic phase composition. The effect of the column temperature on SST was studied at 40��C and 50��C instead of 45��C. In all the deliberate varied chromatographic conditions, maximum tailing factor for BHT peak from standard solution was 1.1, minimum theoretical plate was 12059 and the %RSD of peak areas was maximum 1.9. The system suitability parameters evaluated are shown in Table 6.