Determination of trace anions in organic solvents

Ion chromatography along with matrix elimination was used to reliably deter mine trace levels of anionic contaminants in organic solvents. A 5-ml sampl e volume was injected directly into the instrument without any sample pretr eatment. High-purity deionized water was used to deliver the sample to a pr econcentration column, where the anions of interest were retained while the organic matrix was rinsed to waste. A sodium carbonate eluent eluted conce ntrated anions from the preconcentration column and separated them on a 2-m m pellicular anion-exchange column. The separated anions were detected by s uppressed conductivity. This method was used to determine the anionic conta minants of isopropanol, acetone and N-methylpyrrolidone. Method detection l imits for chloride, nitrate, sulfate and phosphate were all lower than 1 mu g/l. (C) 1999 Published by Elsevier Science B.V. All rights reserved.