Smart methanol sensor based on silver oxide-doped zinc oxide nanoparticles deposited on microchips

We have prepared calcined silver oxide-doped zinc oxide nanoparticles (NPs) by a hydrothermal method using reducing agents in alkaline medium. The doped NPs were characterized by UV/vis, FTIR, and X-ray photoelectron spectroscopy, and by X-ray powder diffraction and field-emission scanning electron microscopy. The NPs were deposited on microchips to result in a sensor that has a fast response to methanol in the liquid phase. Features include high sensitivity, low-sample volume, reliability, reproducibility, ease of integration, long-term stability, and enhanced electrochemical responses. The calibration plot is linear (r(2) = 0.9981) over the 0.25 mmolL(-1) to 0.25 molL(-1) methanol concentration range. The sensitivity is similar to 7.917 mu A cm(-2) mmolL(-2), and the detection limit is 71.0 +/- 0.5 mu molL(-1) at a signal-to-noise-ratio of 3.