Improved Gas Chromatographic Determination of Sorbitan Fatty Acid Esters in Confectionery Products

A method is described for gas chromatographic (GC) determination of sorbitan fatty acid esters in confectionery products as sorbitan monostearate. A sample is homogenized with chloroform, filtered, dried, and saponified with 0.1N NaOH in ethanol 1 h at 80°C. The saponification mixture is acidified, washed with hexane, and dried. Isosorbide, 1,4-sorbitan, and D-sorbitol are each derivatized at 70°C with pyridine, hexamethyldisilazane, and trimethylchlorosilane. GC separation of the polyols as TMS (trimethylsilyl) derivatives was performed on a 2% Dexsil 300 column temperature-programmed from 120 to 250°C at 107 min. The sorbitan monostearate content of the sample was calculated from the polyols, using the appropriate conversion factor. The procedure was applied to ice creams, cakes, and other confectionery products. Average recoveries from samples spiked with 1.0% Span 60 (sorbitan monostearate) were 91-96% for isosorbide, 83-99% for 1,4-sorbitan, and 82-98% for D-sorbitol. The detection limit was approximately 0.01%.