Abstract:

Objective: To develop a high-performance chromatographic method with an evaporative light scattering detector (ELSD) for the quantified determination of hydrolyzed animal protein in dairy products. Methods: Acidic hydrolysis was employed for sample pretreatment. The chromatographic column used for analyte separation was Shim-pack C18 (4.6 mm × 250 mm, 5μm) with 3.8 mmol/L heptafluorobutyric acid/methanol (8:2, V/V) as the mobile phase at a flow rate of 1.0 mL/min. The ELSD drift temperature was set at 50 ℃, and the carrier gas pressure at 350 kPa. The sample load of 10μL was adopted. The content of hydroxyproline determined under these conditions was used to characterize the level of hydrolyzed animal protein in samples. Results: The developed method displayed good linearity over the concentration range of 10 to1000μg/mL, with a determination coefficient of 0.99993 (n = 5) and its detection limit was 5μg/mL. The average spike recovery for hydroxyproline was 99.83%, with 2.77% RSD. Conclusion: This method without sample derivatization has the benefits of simplicity of operation as well as high sensitivity and accuracy, and is applicable for the determination of hydroxyproline.

Key words: HPLC, evaporative light scattering detector, dairy products, hydrolyzed animal protein, hydroxyproline