ION CHROMATOGRAPHY OF ORGANIC-RICH NATURAL-WATERS FROM PEATLANDS .1. CL-, NO2-, BR-, NO3-, HPO42-, SO42- AND OXALATE

Organic-rich natural waters from peat bogs in continental (Switzerland) and maritime (Shetland Islands, Scotland) areas were analysed for Cl-, NO2-, Br-, NO3-, HPO42-, SO42- and oxalate using ion chromatography. These anions can be determined simultaneously in the surface and pore water samples from the continental bogs using a 250-mul injection loop. Using this loop, the detection limits were ca. 5 ng/g for the monovalent anions and SO42- and 10 ng/g for HPO42- and oxalate. An organics-removal cartridge (Dionex OnGuard P) was used to remove humic materials. These cartridges did not significantly affect the measured concentrations of anions in blind standards. Analyses of deionized water treated with these cartridges are not significantly different from those for untreated deionized water. For the maritime bogs, the relatively high concentrations of Cl- (more than 100 mug/g in many samples) and SO42- (up to 50 mug/g) require two separate determinations for complete analyses. A 10-mul injection loop was used to determine Cl-, Br-, and SO42-. A 250-mul injection loop was used to measure NO2-, NO3-, HPO42- and oxalate. In each instance a Dionex OnGuard P cartridge was used to remove humic materials. In addition, a chloride-removal cartridge (Dionex OnGuard AG) was used to remove Cl- when the larger injection loop was used. This cartridge has no significant effect on the measurement of HpO42- at concentrations of 20 ng/g. In each of the bog water chromatograms there were usually a number of unknown peaks. These are probably due mainly to organic anions.