Photoelectrochemical platform for sensing propyl gallate in edible oil samples based on CdTe quantum dots and poly(D-glucosamine)

This paper reports the development of a photoelectrochemical platform based on indium tin oxide (ITO) electrode modified with carboxyl-functionalized cadmium telluride quantum dots (CdTe) and poly(d-glucosamine) (PDG) for the determination of propyl gallate in edible oil samples. The photoelectrochemical (PEC) sensor was designed as ITO/CdTe/PDG and characterized by amperometry and electrochemical impedance spectroscopy. The ITO/CdTe/PDG PEC sensor showed higher photocurrent response for the propyl gallatecompared to the photocurrents obtained for the bare ITO and ITO/CdTe electrodes. The amperograms showed that the photocurrent of the propyl gallate is much larger in the presence of oxygen suggesting that the presence of this molecule in the solution is essential to increase the sensitivity of the system. In addition, high selectivity was obtained when the proposed sensor was evaluated in samples containing other antioxidants and some ions. The linear range of response and detection limit for the determination of propyl gallate were 0.3 to 150 mol L-1 (n = 10) and 0.13 mol L-1, respectively. Recovery tests for propyl gallate in edible oils showed recovery percentages between96.2 and 111.3%.