Electrospray ionization mass spectrometry for the quantitation of albumin in human serum

Capillary reversed-phase liquid chromatography was coupled to electrospray ionization mass spectrometry for determining the concentration of human serum albumin (HSA) in a fresh frozen serum reference material. A biotinylated HSA (bHSA) was prepared and used as an internal standard for the serum albumin determination. The average HSA concentration of the serum sample was determined by mass spectrometry to be 41.5 +/- 2.8 g/L at the 95% confidence limit for the measured value. The HSA concentration of the fresh frozen serum was also assayed using the bromocresol green dye-binding method, producing a value of 42.3 +/- 1.5 g/L. Calibration curves generated from HSA standards spiked with bHSA showed excellent linearity and the relative standard deviation for replicate analysis of a bHSA spiked serum sample was less than 3%.