I have a question concerning the sample preparation of DNA for MALDI analysis.
Why are users including an ammonium salt? I have used 3-hydroxy picolinic
acid with ammonium tartrate and have a good spectra that matches the expected
mass of the analyte, but there is a huge amount of adducts in the spectrum.
The mass of the main peak matches the expected mass not the mass + NH4, so why
the ammonium salt? Most of the adducts were +22 (Na). Before I go off and
investigate how to get rid of the adducts, all comments would be appreciated.
Mike Knierman
Eli Lilly