Used as a reference standard in analytical laboratories for the accurate identification and quantification of 3,4-xylenol in environmental, industrial, or biological samples. Commonly applied in gas chromatography (GC) and high-performance liquid chromatography (HPLC) to calibrate instruments and validate test methods. Ensures reliability in monitoring pollutant levels in air, water, and soil, especially in industrial hygiene and environmental safety assessments. Also utilized in research settings to study degradation pathways of phenolic compounds and to assess exposure in occupational health studies.