Gas chromatographic and mass spectrometric determination of some resin and fatty acids in pulpmill effluents as their pentafluorobenzyl ester derivatives

Abstract

A sensitive gas chromatographic method for the determination of resin and fatty acids commonly found in pulpmill effluents is presented. The acids are extracted from effluent samples at pH 8 by methyl tert.-butyl ether and converted into their respective pentafluorobenzyl ester derivatives. After silica gel column cleanup, sample extracts are analyzed by gas chromatography with an electron-capture detector using a 30-m DB-17 column. Mass spectral data of these esters obtained under electron impact and electron capture negative ion chemical ionization conditions are also described. The abundant and characteristic (M — 181) − ions are used for the identification and quantitation of resin and fatty acids using a selected ion monitoring technique. Using an effluent with a low blank, spiked recovery of a mixture of 15 acids at 1000-, 100- and 10-μg/1 levels is quantitative. Based on a 25-ml sample and a concentration factor of 10, the method detection limit is 1 μg/1 for all acids. Application of this procedure to some Canadian pulpmill samples is also presented.