I am trying to quantitate the molecular weight distribution of PEG and PEG
derivatives (ie proprionic-acid peg) by MALDI tof analysis. I have read a
paper by Williams et al. in Macromolecules (1996), 29:8144-8150 that
describes liquid-phase matrix methods to make this work, but they also
report nice spectra using 5ul alpha-CHCA in CH3CN as substrate and sat'd
sol'n of the same matrix in MeOH:H20:PEG in equal volume of 1mg/ml PEG. I
tried the a-CHCA approach, but cant seem to get it the PEG to fly under
these conditions, and I have toyed around a bit with ratios of analyte to
matrix but still no luck. I have had some helpful suggestions from the
Genetics Institute that doping the matrix with CsCl or AgCl may work (it
works for PS). Does anyone have a protocol for this method, or know of
another sure-fire way to make my peg or peg-cooh fly?
Cheers,
--Gary
=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-
Gary Van Domselaar gvd@redpoll.pharmacy.ualberta.ca
Faculty of Pharmacy Phone: (780) 492-4493
University of Alberta FAX: (780) 492-5305
Edmonton, Alberta, Canada