stigmasterol in standard solutions are also applicable to other sterols. Linearity (95% confidence interval) was given for mass ratios of stigmasterol to dihydrocholesterol ranging from 0.01 to 20 (corresponding to 0.05–100 mg stigmasterol used for silylation, final volume 200 ml). Depending on the sample matrix and on the content of closely eluting sterols, LODs in samples were between 0.1 and 0.5 mg/100 g and LOQs (defined as the lower end of the linear range) ranged from 0.5 to 1.0 mg/100 g.
The inter-day variability of the total analysis method (expressed as RSD for N ¼ 8) was 0.9% for the total sterol content and below 5.0% for contents of individual sterols greater than 5 mg/100 g. Stigmasterol added prior to sample preparation could be recovered to 98.9% and 99.4%, respectively, at the investigated spike levels.