Electrospun modified PAN-porphyrin nanofiber electrode for caffeine detection

Abstract

In this work, caffeine sensitive electrospun polyacrylonitrile-(5,10,15,20-tetra(4-tert butylphenyl)-porphyrin)/carbon felt electrode (PAN-Por/CFE) nanofiber (NF) electrochemical sensor was fabricated. In this manner, this work presents a new approach for simple, improvable and cost-effective electrochemical caffeine sensor by including coating of CFE with PAN-Por NF via electrospinning method. To the best of our knowledge, this is the first study that covers the fabrication of caffeine sensitive electrospun electrochemical sensors that included (5,10,15,20-tetra(4-tert butylphenyl)-Por). In order to obtain this modified electrode, PAN-Por precursors were prepared and then deposited on CFE via electrospinning. Physicochemical characterizations of NFs obtained by adding pure PAN and different ratios of Por were conducted by using scanning electron microscopy, fourier transform infrared, ultra violet visible and polarization optical microscope techniques. Electrochemical characterization of PAN-Por/CFE was performed by cyclic voltammetry, linear sweep voltammetry and differential pulse voltammetry. For the developed caffeine sensor, limit of detection was calculated as 14.06 μM in the linear range of 15–1000 μM. Meanwhile, the limit of quantification was defined as 42.60 μM while for 50 μM caffeine, the relative standard deviation value was calculated as 0.58%. Accordingly, the proposed method was successfully applied for the determination of caffeine in different coffee samples with recoveries ranging from 99.3% to 102.4%.