Date of Award


Document Type

Master Thesis

Degree Name

Masters of Science (Research)


Department of Physical Science

First Advisor

Dr. K.N. Kilcawley

Second Advisor

Dr. A. Furey


Quantification of free fatty acids (FFA) in dairy products by gas chromatography flame ion'^ation detection is an important requirement for qua'ity, research, nutritional, authenticity and legislative purposes. Common procedures are typically variants of either the fatty acid methyl esterification (FAME) or direct on-column injection methods developed more than two decades ago. This study involved the development of an alternative novel derivatization method using butylation, incorporating automation, reducing solvent usage that is applicable for a wide range of dairy products. The accuracy, precision, linearity, limits of detection and limits of quantification of all three methods were assessed for the quantification of FFA in seventeen dairy products. Significant limitations were evident with both the direct on-column and FAME methods. The direct on-column method experienced accumulative column phase deterioration and irreversible FFA absorption due to the acidic nature of the injected extract. The FAME method experienced issues with co-elution of the injection solvent peak with butyric acid that impacted on its quantification, loss of polyunsaturated free fatty acids and the interference from artefact peaks. Quantification of all FFA was achieved across all samples with the novel derivatization method. The novel butylated derivatization step was automated, reducing solvent usage and increasing sample throughput and accuracy. Limits of quantification and detection were comparable to the other methods and the method has significant potential for research and industrial applications.

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