title: Microfluidic chip for peptide analysis with an integrated HPLC column, sample enrichment column, and nanoelectrospray tip.
abstract: Current nano-LC/MS systems require the use of an enrichment column, a separation column, a nanospray tip, and the fittings needed to connect these parts together. In this paper, we present a microfabricated approach to nano-LC, which integrates these components on a single LC chip, eliminating the need for conventional LC connections. The chip was fabricated by laminating polyimide films with laser-ablated channels, ports, and frit structures. The enrichment and separation columns were packed using conventional reversed-phase chromatography particles. A face-seal rotary valve provided a means for switching between sample loading and separation configurations with minimum dead and delay volumes while allowing high-pressure operation. The LC chip and valve assembly were mounted within a custom electrospray source on an ion-trap mass spectrometer. The overall system performance was demonstrated through reversed-phase gradient separations of tryptic protein digests at flow rates between 100 and 400 nL/min. Microfluidic integration of the nano-LC components enabled separations with subfemtomole detection sensitivity, minimal carryover, and robust and stable electrospray throughout the LC solvent gradient.
authors.affiliation: Agilent Laboratories, 3500 Deer Creek Road, Palo Alto, California 94304, USA. hongfeng_yin@agilent.com
authors.forename: Hongfeng
authors.initials: H
authors.lastname: Yin
authors.forename: Kevin
authors.initials: K
authors.lastname: Killeen
authors.forename: Reid
authors.initials: R
authors.lastname: Brennen
authors.forename: Dan
authors.initials: D
authors.lastname: Sobek
authors.forename: Mark
authors.initials: M
authors.lastname: Werlich
authors.forename: Tom
authors.initials: T
authors.lastname: van de Goor
mesh_terms: D002851:Chromatography, High Pressure Liquid / Q000295:instrumentation* / Q000379:methods; D046210:Microfluidic Analytical Techniques / Q000295:instrumentation* / Q000379:methods; D036103:Nanotechnology; D010455:Peptides / Q000032:analysis*; D012680:Sensitivity and Specificity; D012710:Serum Albumin, Bovine / Q000032:analysis; D021241:Spectrometry, Mass, Electrospray Ionization / Q000295:instrumentation* / Q000379:methods
chemical_list: D010455:Peptides; D012710:Serum Albumin, Bovine