AN31 Determination of Anions in Acid Rain by Ion Chromatography

INTRODUCTION The increase in the acidity of wet and dry deposition has been attributed to the increase of S02 and N02 emis- sions from stationary and mobile sources. The problem of acid rain has reached dramatic proportions throughout many regions of the United States, Canada, Europe, and Japan. Monitoring of air and rain are essential for assess . mg the effects of pollutants on global ecology. Ion chromatography (IC) offers the analyst the uniqu advantage of selective and rapid determination of low concentrations of anions in acid rain. The trend toward decreasing anion concentrations in wet deposition for certain areas of the United States! emphasizes the need for the improved sensitivity that IC can provide over other analytical methods. Chemically suppressed IC has secure I 0 od . o t 0 bec f 0 hi h d a pace m aCI ram mom ormg ause 0 Its g egree of accuracy and reliability, and has been specified by the United States Environmental Protection Agency (EPA) as the method of choice for the determination of chloride Phos phate nitrate and sulfate(CI- PO 3- NO - SO2- )wet deposition samples}-4 Several studies employing IC have been conducted to date,5-7 This application note describes the established ion chromatographic method for the determination of anions i rainwater samples extended to the use of microbore columns and accessories. A rainwater standard from the National Institute of Standards and Technology (NIST) was analyzed, verifying the accuracy of the method.