Development of a Gas Chromatography-Tandem Mass Spectrometry Method for the Simultaneous Analysis of 19 Taste and Odor Compounds.

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Title: Development of a Gas Chromatography-Tandem Mass Spectrometry Method for the Simultaneous Analysis of 19 Taste and Odor Compounds.
Author: Viswakumar, Anjali
Advisors: Detelf Knappe, Committee Member
Joel Ducoste, Committee Member
Francis L. de los Reyes III, Committee Member
Abstract: An analytical method was developed to detect and quantify 19 compounds commonly associated with taste and odor (T&O) problems in drinking water. The method can be used by utilities during T&O episodes to quickly and reliably detect T&O compounds and determine their concentrations. Knowledge about the identity and concentration of T&O compounds will greatly aid utilities in the selection of appropriate treatment strategies. Head space solid phase microextraction (SPME) was used to concentrate T&O compounds, and gas chromatography (GC) followed by tandem mass spectrometry (MS/MS) was used to separate, detect, and quantify the T&O compounds. Method development included (1) determination of parent ion mass and retention time, (2) optimization of the ion trap MS/MS instrumental parameters, (3) development of calibration curves, and (4) determination of the method detection limits (MDLs) and limits of quantitation (LOQs) for each compound. For 12 of the 17 targeted T&O compounds with known odor threshold concentrations (OTCs), LOQs were below the OTC. This result suggests that the developed method is capable of detecting developing T&O problems for these 12 compounds and allow utilities to implement treatment strategies before consumers can detect objectionable tastes and odors in their water. The developed method was tested by analyzing three water samples from North Carolina ponds and lakes that experienced algae/cyanobacteria blooms. In addition, Raleigh source and tap water samples were analyzed. Of the 19 targeted T&O compounds, all but 2,4,6 tribromoanisole were detected in the collected samples. In the bloom samples, geosmin, β-ionone, and trans-2,cis-6-nonadienal most frequently occurred at concentrations that exceeded their OTCs, sometimes by a factor of >100. A comparison of results for non-filtered and filtered (0.45 µm membrane) samples suggests that many T&O compounds were predominantly present inside algae/cyanobacteria cells. Only geosmin and β-cyclocitral were present at measurable levels in Raleigh source and tap water. Concentrations in the raw and tap water samples were similar and at levels that were at or below the OTCs of geosmin and β-cyclocitral.
Date: 2010-04-29
Degree: MS
Discipline: Civil Engineering

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