Qualitative and Quantitative Methods for the Quality Control of Ethanol-Based Hand Sanitizers using a Low-Cost Transmission Near Infrared Spectrometer

Alcohol-based hand sanitizers are essential for hand hygiene and help prevent the spread of infectious diseases. This work focuses on the development and validation of qualitative and quantitative methods for quality control of ethanol-based disinfectants using a low-cost handheld transmission spectrophotometer and chemometrics. Calibration and validation samples, in liquid and gel forms, were prepared with ethanol concentrations ranging from 40 to 90 % v/v. The qualitative method involved constructing a model based on data-driven soft independent modeling of class analogy, enabling the identification of hand sanitizers with an ethanol concentration between 60 and 80% v/v. A sensitivity of 100 % was achieved for both the training and validation sets. The evaluation of the specificity of the constructed model showed satisfactory results when analyzing samples containing ethanol at lower and higher concentrations, as well as samples containing other alcohols. The quantitative method was based on a partial least squares regression model for the determination of ethanol in hand sanitizers. The validation study, conducted using the accuracy profile strategy, showed that the developed method was specific, linear, fair, precise, and accurate over the ethanol concentration range of 40-90 % v/v. The developed and validated methods were successfully used to analyze various commercial ethanol-based disinfectants.