| Abstract
| - High-throughput microfluidic processing of protein digests integrated with matrix-assisted laser desorption/ionization (MALDI) mass spectrometry on a compact disk(CD) is described. Centrifugal force moves liquid throughmultiple microstructures, each containing a 10-nL reversed-phase chromatography column. The CD enablesparallel preparation of 96 samples with volumes rangingfrom one to several microliters. The peptides in the digestsare concentrated, desalted, and subsequently eluted fromthe columns directly into MALDI target areas (200 × 400μm) on the CD using a solvent containing the MALDImatrix. After crystallization, the CD is inserted into theMALDI instrument for peptide mass fingerprinting anddatabase identification at a routine sensitivity down to the200-amol level. Detection of proteolytic peptides down tothe 50-amol level is demonstrated. The success rate ofthe CD technology in protein identification is about twicethat of the C18 ZipTips and standard MALDI steel targets.The CDs are operated using robotics to transfer samplesand reagents from microcontainers to the processinginlets on the disposable CD and spinning to control themovement of liquid through the microstructures.
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