Determination of Emerging Contaminants in Iowa Surface Water at Low PPT Levels Using Direct Injection and SPE LCMSMS

摘要

There is increasing interest for testing water for non-regulated contaminants, such as antibiotics, pharmaceuticals, endocrine disrupting chemicals, and others. Existing analytical methods, such as EPA 1694, tend to be labor-intensive, expensive to perform, and optimized for select classes of contaminants. There is a need for extraction procedures that are more generic in nature and accountable for many of the contaminants, as well as a need for a direct aqueous injection procedure that is rapid and cost-efficient to perform. LCMSMS testing methods are often prone to issues with instrument signal drift and/or matrix effects, especially when electrospray interfaces are used. There is a need for suitable internal standards that can appropriately correct for such issues In this study, we contrast a generic SPE extraction procedure that was developed in our lab with a newly-developed direct aqueous injection (DAI) procedure. The effectiveness of labeled internal standards was also evaluated. Spike studies were conducted with surface water samples to examine: (1) effectiveness of the SPE extraction procedure, and (2) effectiveness of selected internal standards to correct for instrument signal drift and/or matrix effects. Finally, emerging contaminants were monitored upstream and downstream of Cedar Rapids and Iowa City using both the DAI and SPE procedures.