Sample pretreatment on a microchip with an integrated electrospray emitter

Peter Lindberg, Andreas P. Dahlin, Sara K. Bergström, Sara Thorslund, Per E. Andrén, Fredrik Nikolajeff, Jonas Bergquist*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

16 Citations (Scopus)

Abstract

This study presents a microbead-packed PDMS microchip with an integrated electro-spray emitter for sample pretreatment prior to sheathless ESI-MS. We prove the concept of analytical functions integrated onto a cm-sized area of a single bulk material. The microchip consists of two PDMS substrates replicated from SU-8 fabricated silicon wafer masters, bonded together after oxidation by corona discharge treatment. The channel within the microchip contains a grid structure that was used to trap 5 μm hypercross-linked polystyrene beads. The beads acted as a medium for sample desalting and enrichment. Electrical contact for the sheathless ESI process was achieved by coating the integrated emitter with conductive graphite powder after applying a thin layer of PDMS as glue. The coating as well as the bond of the PDMS structures showed excellent durability. A continuous spray was obtained from the microchip for over 800 h in a long-term electrospray stability experiment. Desalting and enrichment of neuropeptides from a physiological salt solution was successful by loading the sample onto the packed beads, followed by a washing and an eluting step. The results were obtained and evaluated using a TOF MS. An LOD of approximately 20 fmol (loaded onto the beads) for angiotensin II was obtained from a sample of neuropeptides dissolved in physiological salt solution.

Original languageEnglish
Pages (from-to)2075-2082
Number of pages8
JournalElectrophoresis
Volume27
Issue number11
DOIs
Publication statusPublished - Jun 2006

Keywords

  • Electrospray emitter
  • Microchip
  • PDMS
  • Sample pretreatment

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