Pre-treated pencil graphite modified electrode sensor for melatonin

Since hormones are essential for controlling a wide range of physiological processes in living organisms, sensitive and precise hormone detection methods are needed. In this work, a pencil graphite electrode was pre-treated in 0.1 M KOH solution over many potential cycles. A potential pretreated pencil graphite modified electrode (PPGME) was developed for detecting bioactive molecules and the hormone melatonin (MEL), using phosphate buffer solution as the supporting electrolyte. Various electrochemical parameters, including pH effects, sweep rates, and studies of different concentrations, were investigated for the determination of melatonin. The PPGME was employed for the simultaneous analysis of melatonin and paracetamol. Interference studies for both analytes showed excellent selectivity and a significant peak current response using the PPGME. The detection limit for MEL was determined to be 0.442 µM and this modified PPGME was also applied for the detection and recovery of MEL in a pharmaceutical sample.