High performance liquid chromatographic analysis of lactose-hydrolysed milk

The application of high performance liquid chromatography to the determination of lactose in milk has been investigated. Both ion-exchange and partition modes were employed, and for unmodified milk, returned equivalent values. However, for milk subjected to the action of β-galactosidases, it has been confirmed that at least one significant transferase disaccharide intermediate is chromatographically unresolved during the former resin-based mode, resulting in an erroneously high lactose estimation. Since such transferase oligosaccharides are adequately separated during partition chromatography on amine-bonded silica, it is recommended that resin-based cation-exchange columns are inappropriate for the estimation of lactose in such lactose-reduced milks.