PEAK IDENTIFICATION IN LIQUID CHROMATOGRAPHY BY MEANS OF FLUORESCENCE LIFETIME DETERMINATION
Abstract
Peak identification in liquid chromatography is most often performed on the basis of retention time alone. In many cases, especially in the analysis of complex samples, this is inadequate. A number of successful attempts have been made at providing an additional means of selectivity so that peak identity can be confirmed, the vast majority of which are spectroscopic in nature. This dissertation describes a new method for positive peak identification in liquid chromatography which also relies upon spectroscopy for the additional selectivity. Specifically, the fluorescence lifetime of an eluting compound is measured, which, when combined with chromatographic retention time, provides sufficient information for the unambiguous identification of an unknown. Preliminary experiments leading up to actual "on-the-fly" lifetime measurement are described, followed by demonstration of the principles of the new technique with flow-injection analysis. A detailed discussion of the factors affecting the precision and accuracy of the method is included along with practical application to the chromatographic determination of polycyclic aromatic hydrocarbons in combustion products. Finally, suggestions for future work are made, including experiments designed to advance the understanding of the method itself, as well as potential new applications.
Degree
Ph.D.
Subject Area
Analytical chemistry
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