Gel permeation chromatography (gpc) was applied to the saturate portion of a 450 deg. to 475 deg. C cut of Wilmington crude oil. Selected fractions were analyzed by mass spectrometry, which demonstrated that a separation based on the number of rings was achieved. An early fraction contained 95.5 Weight-percent no-, one- , and two-ring compounds; and a late fraction contained 95.9 Weight- percent three-, four-, five-, and six-ring compounds. The relationship of the experimental results to those predicted from calibration curves relating carbon number to both distillation and gpc is discussed.