Non-enzymatic CuCr₂O₄/GCE amperometric sensor for high sensing and rapid detection of nM level H₂O₂

Herein, spinel CuCr2O4 nanocrystals with multiple mixed valence states have been synthesized through a sol-gel technique and simply modified on the surface of bare glassy carbon electrode (GCE), which achieved high response of non-enzymatic CuCr2O4/GCE to nM-level H2O2 for the first time. In 0.1 M sodium hydroxide solution, the fabricated CuCr2O4/GCE amperometric sensor exhibited a large sensitivity of 886 mu A mM(-1) cm(-2) to H2O2 during linear detection range of 0.3 mu M similar to 8.1 mM. Meanwhile, its detection limit is as low as 160 nM. This superior electrochemical sensing ability is mainly attributed to the synergism of its relatively large electrode active area, high electric conductivity and valence-mixed Cu/Cr redox couplings. In addition, the modified electrode can also accurately detect traces of H2O2 in milk whey, mouthwash and disinfectant solutions, which in turn has potential applications in the above related fields.