Simultaneous determination of bovine alpha-lactalbumin and beta-lactoglobulin in infant formulae by ultra-high-performance liquid chromatography-mass spectrometry.

A reliable ultra-high-performance liquid chromatography-mass spectrometry method for simultaneous determination of bovine alpha-lactalbumin (alpha-La) and beta-lactoglobulin (beta-Lg) was developed. Compared to the previous methods, the developed approach with mass spectrometer operated in selected area monitoring mode offered increased speed and enhanced lower detection limit. A linear gradient mobile phase, consisting of (A) water containing 0.1% trifluoroacetic acid (TFA) and (B) acetonitrile containing 0.1% TFA, and an Acquity UPLC BEH300 C18 column (150mmx2.1mm, 1.7microm) were employed to obtain the best resolution of the target analytes. The accurate quantitation was achieved by employing human alpha-lactalbumin as the internal standard. The established method was extensively validated by determining the linearity (R(2)>or=0.9991), sensitivity (limit of quantitation, 0.15-0.19microgmL(-1)), recovery (94.0-98.7%), precision (relative standard deviation<or=11.1%) and repeatability (relative standard deviation<or=5.7%). It was shown to be a suitable method for simultaneous determination of the major whey proteins in biological samples. Current validated method was successfully applied to the nutrient investigation of infant formulae. Copyright 2010 Elsevier B.V. All rights reserved.