The cyclopentenone prostaglandin HPLC mixture contains all of the major UV-absorbing cyclopentenone prostaglandins and their precursors supplied in methyl acetate. This HPLC mixture contains 100 ?g of the following cyclopentane prostaglandins and precursors: prostaglandin A2, prostaglandin B2, prostaglandin D2, prostaglandin E2, prostaglandin J2, and 15-deoxy-?12,14-prostaglandin J2.