Abstract
CdO-doped Fe2O3 nanocubes (NCs) were prepared by a hydrothermal method using reducing precursors in alkaline medium, and characterized by UV/vis, FT-IR, Raman, and X-ray photoelectron spectroscopy, by X-ray powder diffraction, energy-dispersive X-ray spectroscopy, and field-emission scanning electron microscopy. The NCs were then deposited on a mu-chip with a surface area (similar to 0.0222 cm(2)) to fabricate a sensor for detecting fluoride. Compared to sensor performance using gold-electrodes, the new sensor with microchip exhibits better sensitivity, a wider dynamic range, and a better long-term stability. The calibration plot is linear (r(2) = 0.9764) over the 10.0 nmolL(-1) to 1.0 mmolL(-1) fluoride concentration range. The sensitivity is similar to 2.170 mu A cm(-2) mmolL(-2), and the detection limit (DL, at an SNR of 3) is similar to 1.8 +/- 0.02 nmolL(-1). The sensor is fairly simple, works reliably, requires a sample volume of 70.0 mu L only, and can be easily integrated into a mu-chip.