title: On-line dual microdialysis with ESI-MS for direct analysis of complex biological samples and microorganism lysates.
abstract: A novel dual-microdialysis approach has been developed for fast and efficient fractionation and cleanup for ESI-MS and ESI MS/MS analyses of biological samples. A modified dynamic microdialyzer utilizing two mirror-image serpentine channels, which sandwich a regenerated cellulose membrane of selected molecular weight cutoff, serves as the first stage for the removal of high-molecular-weight components and cellular residue. The second stage employs a hollow microdialysis capillary to remove low-molecular-weight species (e.g., salts) which can degrade or preclude analysis ESI-MS. A protein mixture consisting of 30 microM bovine serum albumin (BSA), 4.0 microM cytochrome c, 2.3 microM ubiquitin, and 9.4 microM bradykinin in 0.5 M NaCl was used to evaluate the performance of this system. Essentially complete removal of both BSA and NaCl was achieved, resulting in high-quality mass spectra containing only the lower molecular weight proteins. After passing through the on-line dual-microdialysis system, a crude bacteria cell lysate yielded clean ESI-mass spectra in approximately 20 min. MS/MS of selected ions demonstrated abundant fragment ions and provided a second-dimension "fingerprint" of the complex cellular fraction. Preliminary application of this technique for direct characterization of microorganism lysates is presented.
authors.affiliation: Environmental Molecular Sciences Laboratory, Pacific Northwest National Laboratory, Richland, Washington 99352, USA.
authors.forename: C
authors.initials: C
authors.lastname: Liu
authors.forename: S A
authors.initials: SA
authors.lastname: Hofstadler
authors.forename: J A
authors.initials: JA
authors.lastname: Bresson
authors.forename: H R
authors.initials: HR
authors.lastname: Udseth
authors.forename: T
authors.initials: T
authors.lastname: Tsukuda
authors.forename: R D
authors.initials: RD
authors.lastname: Smith
authors.forename: A P
authors.initials: AP
authors.lastname: Synder
mesh_terms: D004926:Escherichia coli / Q000737:chemistry; D046911:Macromolecular Substances; D013058:Mass Spectrometry; D017551:Microdialysis / Q000295:instrumentation* / Q000379:methods
chemical_list: D046911:Macromolecular Substances