Methods of investigation Determining functionality of polyols by micro-thin layer chromatography

A description is given of the thin layer chromatography of polyols using 6 × 6 cm plates coated with KSK silica gel, the chromatograms being developed with a Dragendorf reagent based on solvents with adsorption properties similar to those of central polyol units. Under these conditions Rƒ of polyol is only sensitive to the contents of hydroxyl groups (functionality), but is insensitive to molecular weight. The method developed may be used for determining impurities in oligomeric polyols of low functionality. For quantitative analysis use is made of the dependence of Rƒ of the “point” of the chromatographic spot on the amount q of the polyol contained. The linear relation between Rƒ and q is maintained in the concentration range which differs by 2 orders of magnitude and enables impurity content to be analysed with an accuracy of ∼ 3%.