ac400472q_si_001.pdf (1.02 MB)
Coupling Isoelectric Focusing Gel Electrophoresis to Mass Spectrometry by Electrostatic Spray Ionization
journal contribution
posted on 2013-05-07, 00:00 authored by Liang Qiao, Elena Tobolkina, Baohong Liu, Hubert H. GiraultGel electrophoresis has been used
for decades as a high-resolution
separation technique for proteins and protein isomers but has been
limited in the coupling with MS because of low throughput and poor
automaticity compared with LC–MS. In this work, we have developed
an ambient ionization strategy, electrostatic spray ionization, for in situ ionization of proteins or peptides inside a surfactant-free
polyacrylamide gel. The samples can be first separated by isoelectric
focusing in a gel and then quickly in situ detected
by scanning the gel with the electrostatic spray ionization mass spectrometry.
With this strategy, nanograms of proteins or peptides inside a band
are enough to be ionized for MS detection. This method for protein/peptide
spots visualization is sensitive, providing sample molecular weight
information while avoiding spot staining and chemical extraction procedures
that can introduce contaminants and sample loss. Proof-of-principle
results have demonstrated that the electrostatic spray ionization
can produce sample ions from a complex background, and with a spatial
resolution matching the isoelectric focusing, it is therefore a good
choice to couple directly isoelectric focusing gel electrophoresis
with mass spectrometry.