High-Performance SPME/AP MALDI System for HighThroughput Sampling and Determination of Peptides

This paper presents the performance characteristics for a new multiplexed solid-phase microextraction/atmospheric pressure matrix-assisted laser desorption/ionization (SPME/AP MALDI) source configuration for a hybrid quadrupole-linear ion trap instrument. The results demonstrate that thorough optimization of parameters such as SPME coating material, optics configurations, extraction solvents, and fiber capacity provides dramatic sensitivity improvements (>1000*) over previous reports in the literature. The multiplexed SPME plate is capable of simultaneous extraction from 16 different wells on a multiwell plate, eliminating the need for extensive sample preparation. Subfemtomole sensitivity is demonstrated for peptide standards and protein digests with run-run reproducibility ranging from approximately 13 to 31%. This highperformance SPME/AP MALDI system shows potential for high-throughput extraction from biological samples.