Development and Validation of Ecofriendly HPLC-MS Method for Quantitative Assay of Amoxicillin, Dicloxacillin, and Their Official Impurity in Pure and Dosage Forms

Table 4

Experimental results of robustness for the determination of AMOX and DIC with their common impurity, 6-APA, by the proposed HPLC/MS method.

Parameters (%RSD)	AMOX	DIC	6-APA
Acetonitrile/water (60: 40, vol/vol)	1.034	1.121	1.188
Acetonitrile/water (70: 30, vol/vol)	1.019	1.377	1.458
Flow rate (0.4 mL/min)	0.900	0.785	0.290
Flow rate (0.8 mL/min)	1.092	1.579	1.440