Evaluation of sample preservation methods for analysis of selected volatile organic compounds in groundwater at the Idaho National Laboratory, Idaho

First posted September 15, 2022 For additional information, contact: Director, Idaho Water Science CenterU.S. Geological Survey230 Collins RdBoise, 83702-4520 During 2020, water samples were collected from 25 wells completed in the eastern Snake River Plain aquifer and 1 well perched groundwater above at National Laboratory to determine effect of different sample-preservation methods on laboratory determinations concentrations volatile organic compounds. Paired-sample sets each well. One sample set was preserved with hydrochloric acid, one without. Both chilled after collection during shipping for analysis. The analyzed 61 compounds U.S. Survey Quality cooperation Department Energy. A comparison reproducibility analyses co-located unpreserved by a relative percent difference method determined that all pairs statistically equivalent. Using normalized absolute method, 81 found be This study confirms results historical samples, which chilling only, are comparable being currently both acid chilling, thus valid use future geochemical evaluations.