Selective and sensitive determination of lactose in low-lactose dairy products with HPAEC-PAD

The demand for low lactose dairy products is increasing and more different lactose free food is commercially available. The level of lactose in these products decreased during the last years and nowadays a concentration of <0.01% is generally accepted as "lactose free". For the determination of the lactose concentrations in these dairy products a sensitive analysis method is needed. We developed a method for the determination of low concentrations of lactose in a wide range of dairy products. A simple sample preparation with dilution, centrifugation and ultrafiltration is efficient for the isolation of lactose from the sample matrix. In this paper, a new HPAEC-PAD analysis on a CarboPac PA100 column gives a good separation of lactose from the other saccharides. This separation in combination with the PAD detector yields a selective and sensitive method for the quantification at the desired concentrations of lactose in low lactose dairy products.