Determination of Formoterol Fumarate in Pharmaceutical Formulations by Voltammetric Technique using a Novel Methyl Orange Layered Sensor

In this work, cyclic voltammetry (CV) and differential pulse voltammetry (DPV) methods were adopted to selectively and sensitively detect and analyze formoterol fumarate (FF) using an electro polymerized poly (methyl orange) layered carbon paste electrode (PMOLCPE). FF is a widely used bronchodilator which helps in treating bronchospasm and chronic obstructive pulmonary diseases. The characterization of the PMOLCPE and the bare carbon paste electrode (BCPE) were observed via CV technique, electrochemical impedance spectroscopy and field emission scanning electron microscopy. The electrochemically active surface area of PMOLCPE and BCPE was evaluated as 0.0364 cm² and 0.0132 cm², respectively. The characterization information revealed the enhanced electrochemical properties of the PMOLCPE. The study on the impact of the electrolytic pH inferred that the electrochemical oxidation of FF on surface of PMOLCPE involved equal number of electrons and protons. At optimal experimental conditions, the limit of quantification and the limit of detection were determined to be 0.36 µM and 0.11 µM, respectively by CV technique and 0.32 µM and 0.09 µM, respectively, by DPV method. The developed electrode produced significant results towards stability, repeatability and reproducibility, hence validating high efficiency and greater reliability. This work demonstrates the fabricated PMOLCPE as a novel sensor with high affordability and great productivity in the quantification of FF. The applicability of the proposed sensor in real sample analysis is substantiated from the analysis of medicinal sample with great recovery results.