In
chromatography
In chemical analysis, chromatography is a laboratory technique for the Separation process, separation of a mixture into its components. The mixture is dissolved in a fluid solvent (gas or liquid) called the ''mobile phase'', which carries it ...
, endcapping refers to the replacement of accessible
silanol groups in a bonded stationary phase by
trimethylsilyl
A trimethylsilyl group (abbreviated TMS) is a functional group in organic chemistry. This group consists of three methyl groups bonded to a silicon atom minus;Si(CH3)3 which is in turn bonded to the rest of a molecule. This structural group i ...
groups. End-capped columns have much lower residual silanol group activity compared to non-endcapped columns. Endcapped columns show decreased retention for hydrogen bond acceptors, such as ionized bases, and increased retention for
protonated bases.
References
chromatography
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