Capillary electrophoresis to quantitate gossypol enantiomers in cotton flower petals and seed

Gossypol is a toxic compound that occurs as a mixture of enantiomers in cotton plant tissues including seed and flower petals. The (−)-enantiomer is more toxic to non-ruminant animals. Efforts to breed cottonseed with a low percentage of (−)-gossypol requires determination of the (+)- to (−)-gossypol ratio in seed and flower petals. We report a method to quantitatively determine the total gossypol and percent of its enantiomers in cotton tissues using high performance capillary electrophoresis (HPCE). The method utilizes a borate buffer at pH 9.3 using a capillary with internal diameter of 50 μm, effective length of 24.5 cm, 15 kV and cassette temperature of 15 °C. This method provides high accuracy and reproducible results with a limit of detection of the individual enantiomers of less than 36 ng/mL providing base line separation in less than 6 min.