Quick method for estimating free gossypol in cottonseed, meats, collets, and extracted meals

A method for estimating free gossypol (FC) has been developed that decreases sample-determination time from over 2 h to about 25 min per sample. With auto pipetters and bottle-top dispensers, six sample determinations can be completed in approximately 50 min. The method consisted of adding water and acetone separately to a fixed sample weight, mixing, filtering, diluting with 65% acetone, and reading absorbance on a spectrophotometer. Absorbance was plotted against the official American Oil Chemists' Society's FC; method for samples that contained FC between 0.02 and 0.9%. Quadratic least squares regression for 31 samples had a correlation coefficient of r(2) = 0.986 and a standard error of estimated FG of 0.032%.