Used as a reference standard in analytical laboratories for the calibration of instruments such as gas chromatographs (GC) and high-performance liquid chromatographs (HPLC). It ensures accurate identification and quantification of 1,3,5-trimethylbenzene in environmental samples, air quality monitoring, and industrial hygiene testing. Commonly applied in the analysis of volatile organic compounds (VOCs) in air, water, and soil, especially in regulatory compliance testing. Also used in research and development for method validation and quality control in petrochemical and environmental testing labs.