Abstract
Voltammetric methods hold promise for the rapid and sensitive quantification of melatonin. This study reports the direct electrochemical quantification of melatonin using carbon nanotube (CNT) fiber cross-sections as microelectrodes. Six identical highly densified CNT fiber cross-sections were employed to quantify melatonin in the range of 0.05-100 μM. The limit of detection and quantification were 10 and 35 nM, respectively, with a sensitivity of 0.1322 nA/μM. Interference studies with uric acid, hypoxanthine, and ascorbic acid demonstrate its performance. Real-world application was highlighted by measuring melatonin in food, pharmaceutical, and human urine samples.