4.1 The presence of pentane and lighter hydrocarbons in gasolines, naphthas, and similar petroleum distillates interferes in Test Method D2789. Pentane and lighter hydrocarbons are separated by this test method so that the depentanized residue can be analyzed and so the pentane and lighter hydrocarbons can be analyzed by other methods, if desired.

4.2 Under the conditions specified in the test method some C₅ and lighter hydrocarbons remain in the bottoms, and some C₆ and heavier hydrocarbons carry over to the overhead. Expressed as volume percent of charge, the amounts are typically 2 % or less, which is considered adequate for the purpose designated under Scope. It should be recognized, however, that when expressed as volume percent of overhead or of bottoms the percentages can be higher, making this test method unsuitable for any purposes not designated under Scope.