Selective and sensitive determination of capsaicin using polymelamine formaldehyde decorated over carbon nanotubes

Abstract

An electrochemical biosensor based on polymelamine formaldehyde (PMF) supported over oxygen functionalised carbon nanotubes (OCNTs) was designed for selective and sensitive determination of capsaicin. The synergy between the highly porous PMF and conductive OCNTs enhanced the electron transport at the electrode/electrolyte interface and eliminated the interference of common organic and inorganic ions at pH 1. The PMF/OCNT composite exhibited superior selectivity and sensitivity towards capsaicin with a low detection limit of 71.5 nM, a response time of ∼1 minute and a wider detection range of 0.1–500 μM with two linear ranges of 100 nM–240 μM and 240–500 μM and high sensitivities of 960 μA μM⁻¹ cm⁻² and 2900 μA μM⁻¹ cm⁻², respectively. The proposed sensor was successfully applied to the determination of capsaicin in different chilli samples, with the recoveries between 99.2–114%, demonstrating the practical applicability of the sensor.