A Fully Automated Procedure for the Preparation and Analysis of Fatty Acid Methyl Esters

The determination of the fatty acid composition of lipids is an analysis that is widely performed. Typically a manual procedure is used to prepare the lipid sample for analysis, by forming fatty acid methyl esters from the triglycerides, prior to analysis by gas chromatography of the resulting mixture. An automated analogue of a manual procedure using boron triflouride and methanol as derivatisation reagents was developed and a comparison made between the two procedures. The study showed that automation of the sample preparation was viable and gave results, at least as good as the manual version of the method.

Introduction
When an analytical laboratory is faced with a large increase in the number of samples to be run; the economics of the analysis changes significantly. From a cost accounting perspective, the costs associated with any
analysis can be seen as composed of two elements: variable costs (those costs that rise in proportion to the increase in samples analysed) and fixed costs (those costs that remain the same as the number of samples analysed increases). If the aim is to minimise the total cost of the activity, when sample numbers are low, it is relatively important to minimise fixed costs, since these costs will tend to represent the major component of the total cost. However, as sample numbers rise, the proportion of the total cost represented by the fixed costs will fall sharply, the reverse argument will become increasingly true and it will become relatively more important to minimise variable costs (even at the expense of increasing fixed costs). Labour costs associated with sample preparation are usually a large part of the variable cost component of any analysis. As a consequence ,
when faced with an increasing sample workload, automation of the process will be favourable when the savings in the labour component of the variable cost, out-weighs the increase in fixed cost due to the capital spend required. Once it becomes economically favourable, increased automation also offers other significant advantages such as opportunities to: improve the precision of the analysis by reducing the effect of human variability, reduce exposure of laboratory staff to hazardous materials and to minimise the use of environmentally undesirable substances.