ON PROBE IMMUNOAFFINITY EXTRACTION BY MATRIX-ASSISTED-LASER-DESORPTION IONIZATION MASS-SPECTROMETRY/

A simple and effective method has been proposed in this work for combi nation of immunoaffinity extraction with MALDI MS. In this method, an antibody is attached to the surface of a MALDI probe tip via a thin ni trocellulose film, This allows the corresponding antigen to be selecti vely captured and concentrated on the probe tip from complex plasma so lution for MALDI MS analysis, The whole procedure can be completed wit hin 1 h, This combination offers several excellent performance feature s in the analysis of SNX-111, a therapeutic peptide, It combines the h igh specificity of affinity chromatography with the high sensitivity o f mass spectrometry in a rapid analysis, Direct mass detection provide s unambiguous determination by the observation of signals at character istic m/z values. This method has been used successfully to determine the therapeutic peptide at relevant doses.