Expanding our Knowledge of Wet and Total Deposition through Resin Technology: Laboratory-Scale Development at the NADPís Central Analytical Laboratory

L. Green
Central Analytical Laboratory,
National Atmospheric Deposition Program,
Champaign, IL USA

Field and laboratory studies reported in the literature have demonstrated the use of ion exchange resins in monitoring networks to provide time-integrated measures of both wet and total deposition of several ionic species. Such methods may provide a cost-effective way to expand the capacity of NADP monitoring stations to better characterize wet, dry, and total deposition in areas with complex patterns of topography or land cover. In collaboration with the Bates College and the Cary Institute of Ecosystem Studies, the NADP Central Analytical Laboratory (CAL) has embarked on further laboratory-scale testing of resin technology for future network deployment by the NADP.

Researchers have evaluated bulk deposition of sodium, potassium, calcium and magnesium using 1M HCl as the ion extractant, and deposition of sulfate, nitrate and chloride using 1M KI as the extractant. Mixed bed resins have also been evaluated for ammonium and nitrate measurements using 2M KCl as the extractant, and other cations and anions using KI as the extractant.

The CAL is developing analytical methodologies and bench-scale protocols to demonstrate its capability to reproduce the results reported in the literature, and further develop research efforts by Bates College and the Cary Institute. The CAL is currently measuring known samples to verify Method Detection Limits (MDLs), and other data quality parameters. Various commercially-available ion exchange resins and extractant solutions will be evaluated for their ion capture and extraction efficiency. A bench-scale setup will be used to load ion exchange resins with NADP/National Trends Network samples to directly compare previously measured precipitation samples with recoveries from resins.