Isotope labelled Equilenin (E592400), which is a naturally occuring estrogenic steroidal hormone (1,2) isolated from urine of pregnant mares (3). Not found in human urine. Component of conjugated estrogenic hormones. Estrogen. This compound is a contaminant of emerging concern (CECs). Drinking water contaminant candidate list 3 (CCL 3) compound as per United States Environmental Protection Agency (EPA), environmental, and food contaminants.
