A Novel Voltammetric Sensor Developed Based on Nickel Molybdate and Graphene Oxide Nanocomposite for Simultaneous Determination of Acetaminophen and Tryptophan

A highly sensitive hybrid nanocomposite electrode based on nickel molybdate (NiMoO 4 ) and graphene oxide (GO) was developed for the simultaneous determination of acetaminophen (ACP) and tryptophan. To improve the electrochemical performance of the nanocomposite, the ratio of NiMoO 4 :GO was changed, and the best results were obtained with NiMoO 4 (5%)+GO(95%) nanocomposite structure. The electrode surface morphologies, chemistry, and electrochemical properties were identified by scanning electron microscopy, X‐ray photoelectron spectroscopy, X‐ray difraction, and electrochemical impedance spectroscopy. The nanocomposite electrode significantly increased the electrochemical response of ACP and TRP relative to a bare GCE, GO//GCE, and MoO 4 )(5%)+GO(95%)/GCE. The developed nanocomposite electrode demonstrates a linear response toward ACP and TRP. The calibration curves were constituted for ACP with two different linear parts at NiMoO 4 (5%)+GO(95%)/GCE: the first linear part was obtained from 0.1 µM to 1.0 µM and the second linear part from 2.0 µM to 10.0 µM, and the calibration curve was constructed in the concentration range of TRP from 0.6 to 60.0 µM. The detection limits were calculated as 10.0 nM for ACP and 79.8 nM for TRP, respectively. The NiMoO 4 (5%)+GO(95%)/GCE was applied for the quantification of ACP and TRP in a synthetic urine sample with a good recovery range from 89.30 to 105.8, respectively.