On-Line Microdialysis-Electrospray Mass Spectrometry for Automated Desalting of Small-Volume Peptide Samples

• Electrospray ionization mass spectrometry (ESI-MS) is an important tool for biomolecule analysis. Because the salt content of small-volume peptide samples can hamper analyte ionization, such samples require treatment before ESI-MS.The approach described here consists in interfacing ESI-MS with on-line microdialysis which affords rapid desalting and buffer-exchange. On-line microdialysis was performed by means of a hollow fiber (i.d. 200 μm) coupled to fused silica capillaries. Peptide samples were introduced into the capillary flow system as plugs and transferred to the dialysis cell and the electrospray by means of hydrodynamic pressure. As a result, the ionization efficiency of peptidic analytes was increased and adduct formation with, e.g., sodium, was reduced owing to reduced levels of nonvolatile salts. The feasibility of on-line microdialysis-ESI-MS is shown with a proteolytic digest originating from two-dimensional gel electrophoresis.

Ämnesord

NATURVETENSKAP  -- Kemi -- Analytisk kemi (hsv//swe)

NATURAL SCIENCES  -- Chemical Sciences -- Analytical Chemistry (hsv//eng)

Nyckelord

Electrospray ionization

Mass spectrometric detection

Microdialysis

Peptide analysis

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