Title: Determination of (+)-, (−)-, and Total Gossypol in Cottonseed by High-Performance Liquid Chromatography
Author: R.J. Hron Sr., H.L. Kim, M.C. Calhoun, and G.S. Fisher
Journal: Journal of American Oil Chemist's Society
Year: 1999
Volume: 76(11)
Page: 1351 - 1355

Abstract: Gossypol, a pigment in cottonseed, is a polyphenolic, binaphthyl dialdehyde. Due to steric hindrance between the functional groups of the molecule at the bond connecting
the two naphthyl rings, gossypol exists as (+)- and (−)-isomers. Gossypol is physiologically active with the (−)-isomer appearing to be more active and causing temporary infertility in males. It is thus important to know the amounts of isomers in livestock feeds. A quantitative high-performance liquid chromatography (HPLC) procedure was developed for the separation of (+)- and (−)-gossypol contained in cottonseed. This method involves derivatization of gossypol with (R)-(−)-2-amino-1-propanol followed by HPLC separation employing either a Phenomenex Prodigy (5 µ, ODS-3, 100 ×3.2 mm) or a MetaChem Inertsil (5 µ, ODS-3, 100 ×3.0 mm) reversed-phase column eluted with 80% acetonitrile and 20% 10 mM KH2PO4 adjusted to pH 3.0 with H3PO4 at 1.0 mL/min. The (+)- and (−)-gossypol-2- amino-1-propanol complexes eluted at roughly 1.4 and 2.6 min, respectively. It was found that gossypol from Upland (Gossypium hirsutum) seed was rich in the (+)-enantiomer, with the (+)- and (−)-enantiomers in a ratio of about 65:35, respectively, while gossypol from the seed of a Pima (G. barbadense) cultivar (S-6) was slightly richer in the (−)-enantiomer (46.8:53.2).

1. Reference:
Hron, R., Kim, H., Calhoun, M., & Fisher, G. (1999). Determination of (+)-, (−)-, and Total Gossypol in Cottonseed by High-Performance Liquid Chromatography. Journal Of American Oil Chemist's Society, 76(11), 1351 - 1355.

2. Citation
(1) Hron et al. (1999) stated that "the complexes of the (+)- and (-)-gossypol-2-amino-1-propanol was recieved at 1.4 and 2.6 minute, respectively" (p. 1351).

(2) According to Hron et al. (1999), the (+)- and (-)-gossypol enantiomers separation by high performance liquid chromatography was success, 1.4 and 2.6 minute, respectively (p. 1351).

(edited the citation from comment)

(1) Hron et al. (1999) stated that "the complexes of the (+)- and (-)-gossypol-2-amino-1-propanol were received at 1.4 and 2.6 minutes, respectively" (p. 1351).

(2) According to Hron et al. (1999), the (+)- and (-)-gossypol enantiomers separation by high performance liquid chromatography was successful, 1.4 and 2.6 minutes, respectively (p. 1351).