A carbon paste electrode modified with Al₂O₃-supported palladium nanoparticles for simultaneous voltammetric determination of melatonin, dopamine, and acetaminophen

The authors have modified a carbon paste electrode with Al₂O₃-supported palladium nanoparticles (PdNP@Al₂O₃) to obtain a sensor for simultaneous voltammetric determination of melatonin (MT), dopamine (DA) and acetaminophen (AC). The PdNP@Al₂O₃ was characterized by scanning electron microscopy and energy-dispersive X-ray spectra. The sensor can detect DA, AC, MT and their mixtures by giving distinct signals at working voltages of typically 236, 480 and 650 mV (vs. Ag/AgCl), respectively. Differential pulse voltammetric peak currents of DA, AC and MT increase linearly in the 50 nmol L⁻¹ - 1.45 mmol L⁻¹, 40 nmol L⁻¹ -1.4 mmol L⁻¹, and 6.0 nmol L⁻¹ - 1.4 mmol L⁻¹ concentration ranges. The limits of detection are 36.5 nmol L⁻¹ for DA, 36.5 nmol L⁻¹ for AC, and 21.6 nmol L⁻¹ for MT. The sensor was successfully used to detect the analytes in (spiked) human serum and drug samples.

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