Measurement of Alcohol Type and Concentration in Hand Gel Sanitizers During the COVID-19 Era: A Review Article for the Future World Health Pandemic Situation

The COVID-19 pandemic drastically altered public health practices worldwide, highlighting the critical role of hand hygiene in controlling viral transmission. In response, alcohol-based hand sanitizers (ABHS) became essential preventive tools, prompting unprecedented global demand, regulatory adaptations, and scientific scrutiny. This review critically examines the types and concentrations of alcohol used in hand sanitizers, the analytical techniques for their measurement, and the evolving regulatory frameworks that govern their production and use. It synthesizes current knowledge on ethanol and isopropanol efficacy, explores safety considerations such as skin irritation and ingestion risks, and evaluates global compliance challenges, particularly in the wake of counterfeit and substandard products. The review also compares advanced measurement techniques - including GC, HPLC, FTIR, and NMR - for their precision, cost, and usability in different settings. Additionally, it discusses market dynamics during the pandemic, shifting consumer preferences, and key research gaps, notably in standardized testing and long-term safety. By integrating multidisciplinary insights from analytical chemistry, public health, regulatory science, and consumer behavior, this paper offers forward-looking recommendations for improving hand sanitizer quality, safety, and pandemic preparedness. The findings aim to support researchers, manufacturers, and policymakers in developing more robust, effective, and trusted hand hygiene solutions for future global health emergencies. HIGHLIGHTS Comprehensive review of alcohol concentration measurement techniques (GC, HPLC, FTIR, NMR) used to ensure the safety and efficacy of hand sanitizers during the COVID-19 pandemic. Comparative analysis of ethanol and isopropanol in terms of antimicrobial effectiveness, formulation safety, and long-term dermatological impact. Critical evaluation of global regulatory frameworks (WHO, FDA, EU) and their role in preventing counterfeit and substandard hand sanitizers in crisis conditions. Identification of research gaps and future directions, including the need for standardized testing protocols and studies on prolonged sanitizer use. GRAPHICAL ABSTRACT