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New liquid chromatographic methods for the analysis of cationic tensides

Bromilow, Ian David (2001) New liquid chromatographic methods for the analysis of cationic tensides. PhD thesis, University of Leeds.

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Abstract

Cationic tensides are important oleochemicals that are used to prevent adulteration of pharmaceutical preparations and personal care products, as well as being the conditioning agents in domestic fabric softeners. The widespread use of these materials requires quantitative methods for characterising them in raw materials and fully formulated products, whilst "down-the-drain" release necessitates similar methods for trace environmental analysis. Unfortunately, current methods used to quantify cationic tensides are generally non-specific, problematic, or are ill-suited to environmental analysis. There is currently no generic method that can be applied to the quantitation of these materials in all necessary matrices. The aim of this work was to develop new liquid chromatographic (LC) methods for the analysis of the cationic preservative and fabric conditioner actives, before attempting to build the foundations of generic cationic tenside analysis. The development of a new normal phase LC method is reported for the quantitation of the cationic actives present in domestic fabric conditioners. The method yielded high resolution and repeatability, and allowed the quantitation of the homologues endemic in commercial samples. Subsequent hyphenation with mass spectrometry demonstrated the potential for the quantitation of these materials in environmental matrices. -The optimisation and validation of a reverse phase LC method for the analysis of cationic tenside preservatives is reported. Excellent repeatability and resolution were again attained, whilst the new method was also found to demonstrate the inherent sensitivity required for trace environmental analysis. Subsequent hyphenation unfortunately showed that method sensitivity was compromised by ion-suppression, highlighting the need for compromise in the development of LC/MS methods. For both methods, stationary and mobile phase parameters were varied to assess the influence on analyte resolution, and also to gauge the potential for developing a generic liquid chromatographic method for the analysis of these materials. It was observed that many of the commonly held beliefs on the analysis of cationic tensides by reverse phase LC were misconceived. As a result, new insights were made into cationic tenside analysis, which should facilitate the development of a generic LC method applicable to the quantitation of cationic tensides and their hydrophilic biodegradation products in the future.

Item Type: Thesis (PhD)
Academic Units: The University of Leeds > Faculty of Maths and Physical Sciences (Leeds) > School of Chemistry (Leeds)
Depositing User: Ethos Import
Date Deposited: 12 Jan 2012 10:57
Last Modified: 07 Mar 2014 11:21
URI: http://etheses.whiterose.ac.uk/id/eprint/1674

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