Rapid and sensitive determination of hydroxyproline in dairy products using micellar electrokinetic chromatography with laser-induced fluorescence detection

Many reports have focused on the determination of hydroxyproline (Hyp) in blood plasma, urine sample, meat and meat products, however, there are few concerned with the Hyp assay in dairy products for food quality assurance up to now. In this paper, we described a sensitive and automated approach for the determination of Hyp in milk powder, liquid milk, milk drink and soymilk powder samples by micellar electrokinetic chromatography (MEKC) based on in-capillary derivatization for the first time. Under the optimal conditions, derivatization and separation procedure could be completed within 7 min and the detection limit for Hyp was 1.6 ± 0.5 ng mL−1. Comparing with the existing alternatives, the present method exhibited some relevant advantages, including full automation, satisfactory sensitivity, and short analysis time for Hyp assay in dairy products.