Spectrophotometric determination of methyldopa via diazotization- coupling and area under curve methods

Sahar Abdullah Fathi; Nabeel Sabeeh Othman; Amer Thanoon AL-Taee

المؤلفون

Sahar Abdullah Fathi University of Mosul, College of Science, Chemistry Department, Mosul, Iraq.
Nabeel Sabeeh Othman University of Mosul, College of Science, Chemistry Department, Mosul, Iraq
Amer Thanoon AL-Taee University of Mosul, College of Science, Chemistry Department, Mosul, Iraq

الكلمات المفتاحية:

Diazo-coupling reaction، area under curve، spectrophotometric determination of methyldopa

الملخص

Two spectrophotometric methods have been proposed for measuring purified methyldopa (MeD) in pharmaceutical preparations (tablets). The first procedure relies on the diazo - coupling of methyldopa with diazotized p-Nitroaniline (D-PNA) in a basic medium in order to produce a stable and water-soluble azo dye with a colored pigment, measured at 610 nm. The calibration curve from 2 to 17 μg. mL^-1 and the molar absorptivity value is 0.7223 x10⁴ L.mol^-1. cm^-1. The LOD value was 0.0727 μg. mL^-1and the LOQ value was 0.242 μg. mL^-1 The second method based on the area under the curve between 596 to 622 nm. The calibration curve from 1 to 20 μg. mL^-1 is more sensitive than first method and it has a molar absorptivity equal to 0.5470x104 L.mol^-1. cm^-1. The two methods gave good recovery, accuracy and precision that applied in assay of MeD in it is dosages the tablets from two drug companies.

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