Determination of beta-2 microglobulin levels in plasma using a high-throughput mass spectrometric immunoassay system

A high-throughput mass spectrometric immunoassay (MSIA) system for the anal ysis of proteins directly from biological fluids is reported. A 96-well-for mat robotic workstation equipped with antibody-derivatized affinity pipet t ips was used for the parallel extraction of specific proteins from samples and subsequent deposition onto 96-well arrayed matrix-assisted laser desorp tion/ionization time-of-flight mass spectrometry (MALDI-TOFMS) targets. Int erferences:from nonspecificalIy bound proteins were minimized through choic e of appropriate affinity pipet tip derivatization chemistries, Sample prep aration for MALDI-TOFMS was enhanced through the use of hydrophobic/hydroph ilic contrasting targets, which also presented functionalities found to pro mote matrix/analyte crystal growth, Automated mass spectrometry was used in the unattended acquisition of data, resulting in an analysis rate of simil ar to 100 samples/h (biological fluid --> data). The quantitative MSIA of b eta (2)m levels present in human plasma samples is given as illustration.