GLC analysis of poison ivy and poison oak urushiol components in vegetable oil preparations

A procedure is described for the analysis of urushiol content of pharmaceutical preparations containing extracts of poison ivy (Toxicodendron radicans) and poison oak (T. diversilobum) in vegetable oils. The procedure involves extraction of the urushiols from the oily solutions using 90% methanol in water followed by GLC analysis of the extracts. Recoveries of both poison ivy and poison oak urushiols from solutions in corn oil, olive oil, sesame seed oil, and cottonseed oil were calculated. Correlation coefficients (r²) ranged from 0.97 to 1.00, and the coefficients of variations ranged from 3.08 to 7.90%.