Parameters Alterations %RSD for Retention time (n=6)   %RSD for Area (n=6)   %RSD for Assay (n=6)  
    SS BH ET SS BH ET SS BH ET
  Mobile phase -2% 0.2143 0.2812 0.2018 0.2942 0.3782 0.4871 0.2431 0.3872 0.4321
Normal 0.2452 0.1466 0.2167 0.2180 0.3764 0.4813 0.2761 0.4286 0.4982
+2% 0.1462 0.1676 0.1972 0.2943 0.3842 0.4319   0.3108   0.4202  0.4874
  Flow rate -10% 0.3113 0.4961 0.4563 0.1278 0.4411 0.3042 0.4532 0.4022 0.5487
Normal 0.3871 0.5786 0.6431 0.1132 0.5039 0.1892 0.5431 0.4135 0.5982
+10% 0.3217 0.6071 0.4532 0.1484 0.4988 0.2791  0.4596  0.5014  0.4983
  pH -0.2unit 0.3924 0.4254 0.5432 0.2097 0.4373 0.3921 0.3216 0.6165 0.6732
Normal 0.3854 0.4711 0.5761 0.2243 0.4828 0.4506 0.2988 0.6746 0.6178
+0.2unit 0.4116 0.4582 0.5629 0.2198 0.5498 0.5106  0.3116   0.5153  0.6988
  Detection wavelength -0.2unit 0.3132 0.6464 0.2678 0.4173 0.5876 0.2984 0.5473 0.3628 0.2756
Normal 0.3201 0.6919 0.2891 0.4442 0.5342 0.2135 0.6759 0.3684 0.2431
+0.2unit 0.3091 0.5867 0.2289 0.4892 0.5982 0.2007 0.5192 0.3651 0.2998
Table 6: Robustness parameter of SS, BH and ET studied for HPLC method.