Colorimetric determination of cyanide in enzyme-hydrolyzed extracts of dried sorghum leaves

The purpose of this study was to develop a simple and effective procedure for assaying large numbers of sorghum leaf samples for their potential to release cyanide. The procedure involves drying the tissue at 75 degree C (this was accomplished without loss of the cyanogenic glucoside dhurrin), grinding the dry tissue, extracting with water, digesting the extract with an almond meal extract to release cyanide, and determining cyanide in the digest colorimetrically. Results obtained were comparable to those based on distillation of digested samples and potentiometric determination of cyanide in the distillates. The equipment and supplies required for the procedure are relatively inexpensive, and a skilled technician can conveniently assay 70-80 samples/day.