Determination of perchlorate at parts-per-billion levels in plants by ion chromatography

A method for the analysis of perchlorate in plants was developed, based on dry weight, and applied to the analysis of plant organs, foodstuffs, and pl ant products. The method reduced greatly the ionic interferences in water e xtracts of plant materials. The high background conductivity, due to the pl ant matrix, was reduced sufficiently to allow quantitation of perchlorate w ith little or no matrix interference. Ion chromatography (IC) on a microbor e AS16 anion-exchange column and a conductivity detector was used for separ ation and detection of perchlorate from the ionic plant extract. The extrac t was heated to precipitate proteins, centrifuged, exposed to alumina, and filtered through a cartridge filled with divinylbenzene to yield a water cl ear extract for IC analysis, even from highly colored solutions. Heating th e extract and treatment with alumina reduced substantially the ionic conten t of the extracts without loss of perchlorate. (C) 2000 Published by Elsevi er Science B.V.