Copper ion modified graphitic CN nanosheets enhanced luminol-HO chemiluminescence system: Toward highly selective and sensitive bioassay of HS in human plasma.

A high-efficient chemiluminescence (CL) platform for highly selective and sensitive HS detection was constructed on the basis of the quenching effect of S on the copper ion modified graphitic carbon nitride nanosheets (Cu-g-CN NSs) enhanced luminol-HO system. Cu-g-CN NSs with horseradish peroxidase-like catalytic activity were prepared and provide a great improvement for luminol-HO system. The presence of S induced the formation of CuS precipitate on g-CN NSs surface. The precipitate can block the catalytic Cu sites on the g-CN NSs surface, resulting in a great CL decrease of CL system. Based on such a mechanism, a simple, highly selective and sensitive CL biosensor for HS detection was designed. Under the optimized conditions, luminol-HO-Cu-g-CN NSs system gave a decrease of CL intensity with the NaS concentration increasing. The CL biosensor is in a linear range of 10.0 pM-50.0 nM and the detection limit for detecting NaS is as low as 2.0 pM. Moreover, the method here has enjoyed a successful application for determining HS in human plasma samples and the recovery is between 95.7% and 110.0%.