Developing effective analytical method for
sulfadimethoxine (
SDM) detection is highly desirable and vitally crucial for protecting environment safety and human health. Herein, a highly selective and sensitive photoelectrochemical (PEC) aptasensor for accurate detection of
SDM was proposed, which employed
zinc phthalocyanine/
graphitic carbon nitride (ZnPc/CN) nanocomposite as photosensitive material. The ZnPc/CN nanocomposite was constructed by modification of CN nanosheet with visible/near-infrared light responsive
photosensitizer ZnPc. The introduction of ZnPc into CN exhibited amplified PEC response, which was 5.7 and 18.3 times than pure ZnPc and CN, attributed to the enhanced light harvesting ability and improved photoelectric conversion efficiency of such nanocomposite. By using ZnPc/CN and
sulfadimethoxine (
SDM) aptamer as PEC response material and specific probe, a PEC aptasensor was established for
SDM detection. The aptamer was connected to the surface of
chitosan/ZnPc/CN/ITO through the formation of
phosphoramidate bonds between the amino group of the
chitosan and
phosphate group of the aptamer at 5' end. The fabricated aptasensor displayed good detection linearity of 0.1 ~ 300 nM and low detection limit of 0.03 nM (S/N = 3) under optimized conditions, and the potential applicability of the PEC aptasensor was confirmed by detecting
SDM in milk
powder samples.