Sample preparation and reversed phase-high performance liquid chromatography analysis of food-derived peptides

Reversed phase-high performance liquid chromatography (RP-HPLC) is an indispensable technique in food peptide research. This paper briefly reviews the methods for isolation and RP-HPLC analysis of food-derived peptides. A critical aspect is the sample preparation and clean-up. For this, selective precipitation, ultrafiltration, size exclusion chromatography, ion-exchange chromatography and solid phase extraction (SPE) are used. SPE with non-polar or ion-exchange cartridges, is an effective and rapid method for peptide isolation, fractionation and concentration. RP-HPLC is accomplished on C18 silica columns using shallow gradients of acetonitrile containing 0.1% TFA. Detection is by far-UV absorbance although selective detection by fluorometry on-line provides complementary and selective information. HPLC coupling to mass spectrometry (MS) and tandem MS/MS is increasingly applied to food-derived peptides. The research topics and the analytical strategies dealing with food-derived peptides are summarized.