Used as a reference standard in analytical laboratories for the accurate determination and quantification of endosulfan and related pesticide residues in environmental and agricultural samples. Commonly employed in chromatographic techniques such as gas chromatography (GC) or high-performance liquid chromatography (HPLC) to calibrate instruments and validate test methods. Ensures reliable monitoring of endosulfan sulfate, a persistent and toxic degradation product of endosulfan, in soil, water, and food samples. Essential for compliance with regulatory limits and safety assessments in environmental and public health studies.