Visible-light photoelectrochemical sensor for glutathione based on CoFe2O4-nanosphere-sensitized copper tetraaminophthalocyanine–graphene oxide

Simple, fast, and sensitive detection methods are required for reduced glutathione (GSH), a metabolic substance that acts as an indicator for a variety of diseases and is also found in numerous supplements and drugs. Herein, a sensitive and selective photoelectrochemical (PEC) sensor was developed for GSH detection. The novel PEC sensor was fabricated using CoFe 2 O 4 nanoporous spheres and copper tetraaminophthalocyanine–graphene oxide (CuTAPc-GO) as photoelectric materials. Under illumination, CoFe 2 O 4 facilitated the spatial separation of the photogenerated charge carriers in CuTAPc-GO, thereby enhancing the photocurrent signal of the PEC sensor. The influences of pH, CoFe 2 O 4 amount, coating amount, and applied bias potential on the PEC response toward GSH were investigated. Under optimized conditions, the designed PEC sensor presented a wide linear response range for GSH of 0.25–320 μM with a detection limit of 0.016 μM at a signal-to-noise ratio of 3. Moreover, this PEC sensor exhibited excellent selectivity, reproducibility, and stability, showing satisfactory results for the detection of GSH in urine and pharmaceutical drugs.