Analytical method development for measurement of unregulated organic contaminants in aqueous samples using liquid chromatography - tandem mass spectrometry.

摘要

Organic wastewater contaminants (OWCs) such as pharmaceuticals, hormones, and perfluorinated compounds (PFCs) are of growing environmental and public health concern. These OWCs were found in U.S. drinking water supplies according to nationwide studies by the U.S. Geological Survey. Many OWCs are not, however, regulated or routinely monitored in drinking water.;The objective of this dissertation was to develop and optimize analytical methods for trace analysis of unregulated organic contaminants in drinking water sources. Furthermore, household water treatment-processes were studied to measure the efficacy of removal of these unregulated organic contaminants from drinking water samples.;Two liquid chromatography-ion trap mass spectrometry systems (LC-IT-MS/MS) were compared for rapid, reliable and sensitive detection of the most abundant PFCs, perfluorooctanoic acid (PFOA) and perfluorooctanesulfonic acid (PFOS). An ultra performance LC-linear IT-MS/MS achieved the lowest detection limits measured, 0.03pg and 0.24pg for PFOA and PFOS respectively, which were approximately two orders of magnitude more sensitive than an LC-IT-MS/MS. With the increased sensitivity, the direct analysis of PFOA/S without solid phase extraction pre-concentration steps was also demonstrated. In addition, MS methods using Full Scan, Single Ion Monitoring, and MS/MS were compared and optimized for a sensitive analysis of PFCs.;A novel rapid method was created by switching polarity for the simultaneous analysis of twenty unregulated compounds, including pharmaceuticals. Sensitive method detection limits were achieved in the range of sub ng/L to hundreds ng/L for all target compounds. An optimized analytical method was applied to quantify low ng/L levels of these target compounds in field water samples from regions throughout New Jersey. Eight target compounds were measured below 1mug/L and two target compounds (i.e. metformin and estradiol) were measured slightly above 1mug/L in the field water samples.;Finally, granular activated carbon (GAC) and ion resin (Brita(TM)) filtration, ozonation, and microwave heating were tested for efficacy at removing 20 target compounds in drinking water samples. The GAC/ion resin mechanism with adsorption properties demonstrated greater removal of the target compounds than the other two mechanisms. Even this water treatment-process only partially removed these target compounds with its mean removal of ≤66%.