GO/Ag2S/ZnO nanorods coatings for non-enzymatic photoelectrochemical glycine determination at trace levels

Photoelectrochemical (PEC) detection as the accurate sensor detection technology was applied to monitor the low concentration of glycine based on GO/Ag2S/ZnO nanorods coatings, which were fabricated on stainless steel. The maximum photocurrent of 116.8 μA cm−2 was obtained for the samples with the deposition time of 120 s, which was indicating that GO/Ag2S/ZnO samples with the deposition time of 120 s had excellent photochemical properties compared to other samples, including Ag2S/ZnO and ZnO samples. The PEC sensing of GO/Ag2S/ZnO nanorods coatings electrodes against glycine were tested by i-t. The results showed that the GO/Ag2S/ZnO nanorods coatings electrodes have high sensitivity of 5.44 μA−1 nM−1 cm−2, big linear range of 5 nM–99.775 μM and low detection limit of 3 nM. Hence the obtained results confirmed the possibility of the GO/Ag2S/ZnO nanorods coatings electrodes used as PEC sensors for low concentration glycine measurements. If the sensor can be applied to clinical detection, it can not only monitor the content of glycine in patients in real time, but also greatly reduce the risk of kidney stones caused by excessive glycine (Gly) in humans.