Attomole detection of proteins by matrix‐assisted laser desorption/ionization mass spectrometry with the use of picolitre vials

Abstract

Abstract Significant improvements in the absolute detection limits for proteins in matrix‐assisted laser desorption/ionization mass spectrometry (MALDI‐MS) are demonstrated by the application of so‐called picolitre vials. By the reduction of the sample volume from a few μL down to 250 pL and simultaneous reduction of the sample spot area from a few mm 2 down to 0.01 mm 2 , low attomole detection limits are obtained for bradykinin and cytochrome c . The detection limit in a single‐shot mass spectrum of bradykinin is estimated to be as low as 250 zeptomol. These are currently the lowest amounts of protein and the smallest volumes analyzed by MALDI‐MS.