Portable platform for rapid and indirect photometric determination of water in ethanol fuel samples

We have developed a simple, fast, portable, inexpensive, and indirect method for the determination of water in ethanol fuels. The addition of an excess amount of water is the most simple and common method of adulterating these fuels. Such procedure can adversely affect the performance of the vehicle. Our system uses a laboratory-made photometry device to monitor the formation of complexes between ethanol and cerium(IV). These reactions produce deep orange–red solutions. The limit of detection and the analytical sensitivity were estimated to be 0.22% v/v (water in ethanol) and 0.11 (% v/v)−1, respectively. The developed platform was satisfactorily robust with respect to the changes in temperature and stability of the reagents during storage. The measurements were accurate at the 95% confidence level compared with data obtained by Karl Fischer titration.