I have samples (dyes and its hydrol. products) which contain lot of sodium
salts. The presence of high concentrations of sodium is caused by the
nature of the dying process (alkaline medium and presence of the large
amount of sodium salts in an exhausting dyeing process) and our primary aim
was to make the monitoring of the hydrolysation process as simple as
possible. So we decided to optimise the determination of our compounds
using ammonium salt to suppress the formation of sodium adducts. Moreover,
we were limited to the negative range only (under no conditions we were
able to obtain signals in positive mode) and the concentration of ammonium
salt we choose was optimal, showing minimal number of sodium adduct
signals. Additional desalting step will be quite uneasy because of the very
low pKa of the sample itself (SO3- groups). Also the acidic nature of the
matrix used, HBB, helped to reduce the number of sodium adducts signals.
Well, the question is, do I have another possibility to reduce the
influence of sodium adducts?
Thanks in advance,
Jan Havlis, Ph.D.
Laboratory of HPLC
MALDI TOF MS Laboratory
Department of Analytical Chemistry
Faculty of Science, Masaryk University
Kotlarska 2, CZ-611 37 BRNO, Czech Republic
phone.: 420-5-41129495, 420-5-41129276
fax: 420-5-41211214
e-mail: jdqh@chemi.muni.cz
URL http://www.chemi.muni.cz/~jdqh/index.html
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