Development and validation of GC-FID method for the determination of ethanol residue in marjoram ointment.

Our study describes the procedure development and validation of the GC-FID method for the determination of ethanol content in marjoram ointment. At the validation procedure linearity ranged from 1 x 10(-4)% to 1 x 10(-1)%, limit of detection was 5 x 10(-5)%, relative standard deviation for precision RSD = 1.07%, relative standard deviation for intermediate precision RSD = 1.43% and good recoveries (average 97,47%) were obtained. It is suggested after the analysis of ethanol content in marjoram ointments from different producers that the method is intended for routine standardization assays of ethanol. From the data of validation criteria it is suggested that the method is suitable for the determination and for the quality identification of ethanol residue in pharmaceutical products.