Mono-2-ethylhexyl phthalate (MEHP) is the primary monoester metabolite of di(2-ethylhexyl) phthalate (DEHP), a common plasticizer. It is widely used in scientific research, particularly in toxicology, endocrinology, and environmental studies, to assess the biological impacts of phthalate exposure, including endocrine disruption and reproductive toxicity. As an analytical standard, MEHP serves in laboratory settings for calibration and quantification in techniques such as HPLC, GC-MS, and other chromatographic methods to detect phthalate metabolites in biological fluids, environmental samples, and consumer products. It is not typically used as a plasticizer itself but rather as a reagent or reference material. Due to its potential health risks, including hormone disruption, it should be handled with appropriate personal protective equipment and in controlled environments.