Development of a method for quantitative analysis of the major whey proteins by capillary electrophoresis with on-capillary derivatization and laser-induced fluorescence detection

• Published in: Journal of separation science Vol. 28; no. 9-10; pp. 935 - 940
• Main Authors: Veledo, María Teresa, de Frutos, Mercedes, Diez-Masa, José Carlos
• Format: Journal Article
• Language: English
• Published: Weinheim WILEY-VCH Verlag 01.06.2005; WILEY‐VCH Verlag
• Subjects: Capillary electrophoresis; Electrophoresis, Capillary - methods; Lactoglobulin; Laser-induced fluorescence; Lasers; LIF; Milk Proteins - analysis; On-capillary derivatization; Quantitation; Reference Standards; Spectrometry, Fluorescence - methods; Whey Proteins
• ISSN: 1615-9306; 1615-9314
• DOI: 10.1002/jssc.200500016

The main whey proteins have been derivatized on‐capillary with 3‐(2‐furoyl)quinoline‐2‐carboxaldehyde (FQ) and analyzed using a laboratory‐made capillary electrophoresis apparatus provided with a laser‐induced fluorescence detector. Several parameters controlling on‐capillary derivatization of proteins, including pH, mixing time, reaction time, concentration of the reagents (potassium cyanide and FQ), and reaction temperature, were optimized. Coefficient variations were lower than 1% for migration time and 7% for peak height. Assay detection limits for the different proteins were in the range 5 nM to 10 nM. The method developed was applied to the separation of the major whey proteins in a laboratory‐made cheese whey and in an infant food formulated with milk. In addition, the β‐LG content of these samples was quantitated. The results showed good agreement with those given by an RP‐HPLC method and with those reported in the literature.