Fast determination of the degree of methyl esterification of pectins by head-space GC

A new, fast method for the quantitative analysis of methoxyl groups in pectin using head-space gas chromatography (HS-GC) has been developed. With this method, results were obtained which were in reasonable agreement with the conventional HPLC method, and the reproducibility of the measurements is high. The advantages of the HS-GC method are that only a small amount of sample (2 mg) per analysis is needed, the chromatogram shows a nice symmetrically shaped methanol peak which is very easy to integrate, the sample preparation for HS-GC is short and easy, and for soluble pectins the sample in the head space vial can also directly be used for analysis of the galacturonic acid content and the degree of acetylation.