Oxidative losses of anthracene, acenaphthylene, and benzo[a]pyrene during Florisil and silica gel cleanup using diethyl ether containing peroxides

Abstract

In the analysis of samples for nonpolar trace organic compounds, a cleanup procedure is often required to remove interfering compounds. Columns of Florisil (magnesium silicate) and silica gel (silicic acid, SiO/sub 2/ x H/sub 2/O) are frequently used for this purpose. Occasionally, the occurrence of unexpected and undesired processes may be detected and eliminated before the modification is incorporated into ongoing analytical protocols. This paper describes such an experience involving acenaphthylene, benzo(a)pyrene, anthracene, and anthracene-d/sub 10/. The last compound has been recommended for use as an internal standard (IS) compound. Toward the goal of the development of a cleanup method which would allow the recovery of a range of neutral compounds following the extraction of filters used to sample ambient air, Florisil column chromatography was tested using solvent mixes of pentane and diethyl ether. Hexane:diethyl ether has been recommended for use in the cleanup of pesticide-containing extracts. Pentane was substituted here for hexane because of its greater volatility. It was hoped that the pentane:diethyl ether solvent mix ratio could be adjusted to allow the simultaneous recovery of the PAH compounds in the same eluant fraction. Recovery studies were carried out using a standard solution of pesticides and PAHs.