Column chemistry

[prabakaranmpharm]

whats difference B/w inertsill column and shield column

[tom jupille]

"Inertsil" is a brand name for a line of columns from GL Sciences (I think); a wide range of bonded phases are sold under the Inertsil trade name. I think (but am not sure!) that they all use the same underlying silica.

"Shield" is a very general term that can mean different things depending on the vendor. You need to consult the vendor's specification sheet.

[Gerhard Kratz]

Most common meaning of "Shield" is the use of an embedded polar group as a spacer between the silica surface and the alkyl chain. It is possible that GL Science is using silica produced by a manufacturer in Japan. They deliver to many chromatography companies. That's for the basic silica. Silanes are produced by different companies, mostly not known by HPLC endusers.
But please follow Tom's advice and ask your vendor. If you want to have a list of Silanes, used to manufactur RP18 materials, please let me know. I will send it to you by e-mail.

[FragranceChem]

I've never used a "shielded" column, but I'm assuming that the embedded polar group is used to reduce interactions between basic compounds and silanols which would reduce peak broadening of basic compounds without having to use something like TEA.

As for Inertsil Tom is correct; it is a registered trademark of GL Sciences.

[carls]

SymmetryShield is the brand name for Waters' polar embedded bonded phase for example RP-18. Inertsil ODS-EP is their version of a C18 with a polar embedded group. Waters claims the polar group they use is different and patented. Due to these and other differences there's no way to know beforehand if one can be replaced with the other.

[HW Mueller]

And I thought that "polar embedding" was used to prevent dewetting and extend the use of the hydrophobic ODS to more polar compounds. Certainly, in my hands polar compounds did indeed get better "treatment" by poloar embedded columns.