Development of a method for quantitative analysis of the major whey proteins by capillary electrophoresis with on-capillary derivatization and laser-induced fluorescence detection.
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 beta-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.
Veledo
María Teresa
MT
Institute of Organic Chemistry, Juan de la Cierva 3, 28006 Madrid, Spain.
de Frutos
Mercedes
M
Diez-Masa
José Carlos
JC
D019075:Electrophoresis, Capillary / Q000379:methods*; D007834:Lasers; D008894:Milk Proteins / Q000032:analysis*; D012015:Reference Standards; D013050:Spectrometry, Fluorescence / Q000379:methods*; D000067816:Whey Proteins
D008894:Milk Proteins; D000067816:Whey Proteins