Miniaturizing sample spots for matrix-assisted laser desorption/ionization mass spectrometry

The trend of miniaturization in bioanalytical chemistry is shifting from technical development to practical application. In matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS), progress in miniaturizing sample spots has been driven by the needs to increase sensitivity and speed, to interface with other analytical microtechnologies, and to develop miniaturized instrumentation. We review recent developments in miniaturizing sample spots for MALDI-MS. We cover both target modification and microdispensing technologies, and we emphasize the benefits with respect to sensitivity, throughput and automation. We hope that this review will encourage further method development and application of miniaturized sample spots for MALDI-MS, so as to expand applications in analytical chemistry, protein science and molecular biology.