Detection of Toxic Contaminants in Alcohol-Based Hand Sanitizers Using Infrared Spectroscopy

Recent fatalities due to methanol and 1-propanol toxicity in alcohol-based hand sanitizers has led the U.S. Food and Drug Administration (FDA) to ban 594 different hand sanitizer brands. The FDA also introduced methanol testing in alcohol-based hand sanitizers before allowing the products to enter the United States This requirement creates a need for inexpensive, rapid, and portable testing methods to measure methanol and 1-propanol concentrations in alcohol-based hand sanitizers. Here we study the performance of infrared (IR) spectroscopy for measuring methanol and 1-propanol concentrations in an alcohol-based hand sanitizer, and compare the performance of two portable spectrometers, Texas Instruments near-infrared (NIR) spectrometer (TI NIR) and NeoSpectra mid-infrared (MIR) spectrometer. The IR absorbance spectra were measured in transmission mode at different path lengths for 52 different hand sanitizer samples spiked with 0%–1% v/v concentrations of methanol and 1-propanol. A partial least-squares regression analysis shows ability to detect contaminant concentrations with a correlation coefficient of determination ( r 2 ) up to 0.99 and root mean square error of prediction as low as 0.34% v/v.