The separation and characterisation of sorbitan esters using gas and liquid chromatographic techniques

Humphrey, Julie L.

Abstract

The aim of the work carried out was to develop an analytical method for characterising sorbitan ester surfactants, which could be used to monitor their manufacture and establish structure activity relationships. HPLC was the first analytical technique used, however despite evaluating various stationary and mobile phases a repeatable method could not be found. High temperature GC with splitless injection was then tried. A range of single polyol esters of varying fatty acid chain lengths were prepared and analysed to establish the ester species that would elute from the column. Using optimised conditions for the injector, detector and final oven temperature of 380 degC and a DB1-ht column, it was found that all possible ester species elute for the short chain fatty acid esters studied. However as the chain length increases the number of ester species eluting decreases, for the longer fatty acid chain length esters based on oleic and stearic acid the sorbitan and sorbitol tri esters are the largest esters to elute. HT-GC analysis of a range of manufactured sorbitan mono esters based on palmitic, stearic and oleic acid was successful with all the mono ester species separated and identified and these separated from the di and tri esters. Validation of the method with sorbitan mono oleate showed that the method was precise and therefore a suitable method for characterising sorbitan mono esters. HT-GC with on-column injection was also investigated and it was found that for the longer chain fatty acid esters more ester species eluted than when using splitless injection. Validation would be required to establish the precision of the method, however it may also be a suitable method for characterising sorbitan esters.

Citation

Humphrey, J. L. (2007). The separation and characterisation of sorbitan esters using gas and liquid chromatographic techniques. (Thesis). University of Hull. Retrieved from https://hull-repository.worktribe.com/output/4208710

• Thesis Type: Thesis
• Deposit Date: Aug 15, 2011
• Publicly Available Date: Feb 22, 2023
• Keywords: Chemistry
• Public URL: https://hull-repository.worktribe.com/output/4208710
• Additional Information: Department of Chemistry, The University of Hull
• Award Date: Nov 1, 2007