Used in environmental and industrial laboratories for calibration of analytical instruments to measure phenol levels in water and wastewater. Ensures accurate detection of phenolic compounds, which are toxic and regulated pollutants. Commonly applied in quality control for pharmaceutical, chemical, and petrochemical industries where phenol is a raw material or byproduct. Also used in validation of test methods such as spectrophotometry and high-performance liquid chromatography (HPLC). Helps maintain compliance with safety and environmental regulations by providing reliable reference concentrations.