Forced volatilization cleanup for gas chromatographic assay of pesticide residues

Abstract

A major deterrent to the widespread routine application of gas chromatographic segregative techniques and selective detectors to qualitative and quantitative pesticide and other residue evaluation has been “poisoning” of volatilization chamber and column by extraneous extractives. This present note is prompted by the recent publication by STORHERR and WATTS (1) of their “sweep co-distillation” cleanup method, which is a version of our “forced volatilization” cleanup technique [OTT and Gunther (2)] as applied to butterfat. The final versions of our apparatus were best suited to cleanup of certain pesticides in butterfat, but the intermediate versions, described herein and in part by Gunther (3) were applicable with good recoveries to a variety of substrate extractives including the very intractable extractives mixture from alfalfa. All these devices physically separate gas chromatographable compounds from those compounds not gas chromatographable and provide a simple and versatile approach to the cleanup of stripping solutions to eliminate many extraneous extractives for almost any subsequent analytical operations.