Highly sensitive electrochemiluminescent sensing platform based on graphite carbon nitride nanosheets for detection of pyrophosphate ion in the synovial fluid

Graphite carbon nitride nanosheets (g-C3N4 NSs) are the promising metal-free polymer-like semiconductor nanomaterials, which exhibit excellent electrochemiluminescence (ECL) behavior. The g-C3N4 NSs modified the glass carbon electrode showed the obvious ECL response using 10 mM S2O82− as the co-reactant at the scan rate of 0.1 V/s. The presence of Cu2+ would quench ECL emission due to the photo induced electron transfer (PET). Pyrophosphate anion (PPi), an important anion in several bioenergetics and metabolic processes, can chelate with Cu2+ with a strong affinity. The introduction of PPi could release Cu2+ from Cu2+-g-C3N4 NSs system, resulting in the ECL recovery. The dosage of Cu2+ and the ECL recover time were further investigated. Under the optimized condition PPi can be detected in the range of 2.0-800 nM with the detection limit of 75 pM based on 3ơ/slope. This ECL sensor also possessed good selectivity to PPi, and has been used to detect PPi in the synovial fluid.