A label-free photoelectrochemical sensor of S, N co-doped graphene quantum dot (S, N-GQD)-modified electrode for ultrasensitive detection of bisphenol A

S, N co-doped graphene quantum dot (S, N-GQD) materials have been composited via a one-pot pattern and used as photosensitive materials to construct a label-free photoelectrochemical (PEC) sensor. The PEC experiments show an enhanced photocurrent response toward Bisphenol A (BPA) sensing due to the increased charge transfer rate and the enhanced absorption of visible light. Compared with dark conditions, the photocurrent signal (-0.2 V vs. SCE) is greatly increased because of the effective oxidation of BPA by photogenerated holes and the rapid electron transfer of S, N-GQDs on the PEC sensing platform. Under optimal conditions linear current response to BPA is in two ranges of 0.12-5 mu M and 5-40 mu M. The limit of detection is 0.04 mu M (S/N = 3). The designed sensor has enduring stability and admirable interference immunity. It provides an alternative approach for BPA determination in real samples with recoveries of 99.3-103% and RSD of 2.0-4.1%.

Automated summary

S, N co-doped graphene quantum dot (S, N-GQD) materials were synthesized and used as photosensitive materials in a label-free photoelectrochemical (PEC) sensor. The materials exhibited enhanced photocurrent response towards Bisphenol A (BPA) sensing, improved charge transfer rate, and increased absorption of visible light. The sensor showed linear current response to BPA within two ranges, with a detection limit of 0.04 μM and good stability and interference immunity.