2,5-Di-t-amyl-p-benzoquinone: an antioxidant encountered during the analysis of human tissues.

The title compound was found in extracts of several human tissues, including neurological tumors, adult brain and fetal brain. It was also present in adhesive tapes used in the laboratory to label glassware, but not in sufficient quantities to be responsible for contamination of the tissues. No source of contamination was found in the hospital. One possible source is an antioxidant used in rubber manufacture. Analytical data are also given for related benzoquinones and hydroquinones.