Abstract
In the present work, we developed a simple, sensitive and inexpensive method to determine dopamine hydrochloride using potassium ferricyanide-Fe(III) by spectrophotometry. The results show that Fe(III) is deoxidized to Fe(II) by dopamine hydrochloride at pH 4.0, and then Fe(II) reacts with potassium ferricyanide to form a soluble prussian blue (KFeIII[FeII(CN)6]). The absorbance of this product was monitored over time using a spectrophotometer at an absorption maximum of 735 nm, and the amount of dopamine hydrochloride could be calculated based on the absorbance. A good linear relationship of the concentration of dopamine hydrochloride versus absorbance was observed, and a linear regression equation of A = 0.022 + 0.16921C (μg mL−1) was obtained. Moreover, the apparent molar absorption coefficient for the indirect determination of dopamine hydrochloride was 3.2 × 104 L mol−1 cm−1. This described method has been used to determine dopamine hydrochloride in pharmaceutical, banana, urine and serum samples with satisfactory results.
