Used as a reference standard in analytical chemistry for the calibration of instruments such as gas chromatographs (GC) and high-performance liquid chromatographs (HPLC). Commonly employed in environmental testing to detect and quantify aromatic hydrocarbons in air, water, and soil samples. Also utilized in quality control processes within the petrochemical and pharmaceutical industries to ensure accurate measurement of trimethylbenzene isomers. Its precise concentration allows for reliable identification and quantification of 1,3,5-trimethylbenzene in complex mixtures.