Chip-based nanovials for tryptic digest and capillary electrophoresis

A method for performing tryptic digests in chip-based open vials with volum es of 15 nl has been developed. Working in an enclosed environment with inc reased humidity counteracted the evaporation of water from the vials during the reaction. Peptide maps of native myoglobin were obtained with capillar y electrophoresis and compared with the results of digests performed in con ventional 100-mu l volumes. The peptide maps, after reactions performed in conventional plastic vials and chip-based vials, showed similar patterns. T he reaction showed to be more efficient in the chip-based vials compared to digests performed in conventional plastic vials. The increased efficiency was probably due to the large differences in surface-to-volume ratios and s urface dependent reactions. The lowest amount of myoglobin utilized to perf orm one single digest in a chip-based vial was 12 ng. The corresponding amo unt of trypsin used was 0.2 ng. (C) 1999 Elsevier Science B.V. All rights r eserved.