An ultrasensitive chemiluminescence assay for 4-nitrophenol by using luminol-NaIO4 reaction catalyzed by copper, nitrogen co-doped carbon dots.

A chemiluminescence (CL) assay on the basis of the tremendous enhancing effect of copper and nitrogen co-doped carbon dots (Cu,N-CDs) on the luminol-NaIO4 reaction was introduced for the determination of nanomolar levels of 4-nitrophenol (4-NP). Cu,N-CDs were synthesized by a hydrothermal approach and characterized by TEM, XRD, EDX, and FTIR analysis. The potential CL mechanism was elucidated by recording the CL spectrum and by evaluating the influence of reactive oxygen species. It was found that 4-NP remarkably inhibited the luminol-NaIO4-Cu,N-CDs reaction and reduced the CL signal of the reaction. This fact was applied for developing a CL assay for 4-NP. Under the optimized conditions, 4-NP could be determined in the concentration range of 0.25 to 150 nM, with a detection limit as low as 0.06 nM. This assay was successfully exploited for the analysis of 4-NP in real environmental samples.