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GPC/SEC-MS
Posted: Thu Sep 18, 2014 5:00 pm
by jabolko
Hello to everyone,
i am writing to ask if someone can tell me which salts can be used in GPC-MS technique, for improving separation and ionization of compounds?
Thank you in advance for answers.
Best Regards,
Jabolko
Re: GPC/SEC-MS
Posted: Fri Sep 19, 2014 2:10 pm
by JMB
Since GPC/SEC separations are based solely (or should be) on molecular size (correlates to MW, roughly) why do you think that addition of a salt would help the separation ??
Re: GPC/SEC-MS
Posted: Fri Sep 19, 2014 10:33 pm
by Karen01
Since GPC/SEC separations are based solely (or should be) on molecular size (correlates to MW, roughly) why do you think that addition of a salt would help the separation ??
It is a standard way of preventing mixed mode chromatography in GPC/SEC so that retention is due only to size exclusion.
- Karen
Re: GPC/SEC-MS
Posted: Sat Sep 20, 2014 9:22 am
by jabolko
use of salts and GPC samples prevent interaction with column..as Karen said retention is then only due to size exclusion ...
I want to connect GPC / SEC with MS detector..so I would like to know if someone doing this to tell me which salts you are using here ?? Which one kind for polar and nonpolar components for ..
Regards,
Jabolko
Re: GPC/SEC-MS
Posted: Sat Sep 20, 2014 1:08 pm
by JMB
For ESI-MS, you generally need a volatile salt, e.g. ammonium acetate, that will not deposit in the ionization source.
Some MS instruments with a particular source geometry (orthogonal) allow the use of traditional, non-volatile salts (e.g. phosphates or NaCl); but even they eventually succumb to the presence of solid deposits and cease to function properly until the source is cleaned.