Microfabricated polymer devices for automated sample delivery of peptides for analysis by electrospray ionization tandem mass spectrometry

Delivery of proteins and peptides to electrospray ionization mass spectrome ters (ESI-MS) has been demonstrated using glass and quartz microfabricated devices. This paper reports the construction and use of poly(dimethylsiloxa ne) (PDMS) microfabricated soft polymer devices with mass spectrometry for protein analysis. The PDMS devices were fabricated using replica molding ag ainst a patterned photoresist generated by photolithographic techniques. Th e PDMS devices were connected to the mass spectrometer via a derivatized tr ansfer capillary and samples were transferred by electroosmotic pumping. Th e formulation of PDMS wais optimized for compatibility with ESI, and the de vices were tested for performance. The practical application of PDMS device s was demonstrated by the identification of rat serum albumin separated by 2-D gel electrophoresis. Extended contact of the sample with the surface of the PDMS device did not significantly affect the sample analysis, and the limit of detection for samples run on:a PDMS device was comparable to the l imit of detection achieved on glass devices. This study suggests that PDMS devices fabricated using replica molding are compatible with ESI-MS, This w ill potentially lead to the construction of inexpensive microfabricated dev ices with complex,designs and advanced functionalities.