Abstract:
Ethanol-based disinfectant spray is widely used during COVID-19 to prevent bacteria and viruses. The ethanol content of the disinfectant spray must be more than 70% v/v. Analytical methods for evaluating the ethanol content in the disinfectant spray should be simple, rapid, and reliable. This study determined ethanol content in disinfectant spray through alcohol oxidation and color photo analysis via mobile phone. The chemical reagents used are potassium dichromate (K2Cr2O7) solution, ethanol standard, and ethanol spray samples. The color models (RGB) were used to monitor a color change from orange (Cr6+) to green (Cr3+) in the reaction using the application PANTONE on a mobile phone and further converted into absorbance. The red color (R) was selected for the analysis as it exhibited the best linear correlation with ethanol concentration, with a coefficient of determination (r2 = 0.9933), and the linear equation (y = -0.0022x + 0.4333). The limit of detection (LOD) for this method was determined to be 39.58 %v/v, which demonstrates the capability of this method for efficient detection of ethanol in alcohol spray. The concentration analysis of ethanol in the sample by measuring the color intensity from mobile phone camera results is similar to the analysis using UV-Vis spectrophotometry techniques. This experiment helps students develop practical skills in quantifying ethanol levels in disinfectant spray. Designed for high school chemistry labs with limited equipment, it encourages exploration of digital imaging technology and emphasizes portability, cost-effectiveness, and quick results for a comprehensive learning experience.