GPC/SEC-MS

[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

[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 ??

[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

[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

[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.