An electrochemical sensor for the sensitive determination of nitrites based on Pt-PANI-graphene nanocomposites

A new sandwich structure nanocomposite of Pt nanoparticles supported on PANI modified graphene was synthesized and used for fabricating a nitrite sensor. The morphology and composition of the nanocomposites were characterized using transmission electron microscopy and X-ray diffraction. Electrochemical investigations indicated that the nanocomposites possess an excellent electrochemical oxidation ability towards nitrites. The sensor exhibited two linear ranges: one from 0.4 mu M to 0.99 mM with a correlation coefficient of 0.9974 and a sensitivity of 485.5 mu A mM(-1) cm(-2); and another from 0.99 mM to 7.01 mM with a correlation coefficient of 0.9981 and a sensitivity of 154.3 mu A mM(-1) cm(-2). The limit of detection (LOD) of this sensing system was 0.13 mu M at a signal-to-noise ratio of 3. Additionally, the sensor exhibited good reproducibility, long-term stability, and anti-interference performance.