Endcapping

In chromatography, endcapping refers to the replacement of accessible silanol groups in a bonded stationary phase by trimethylsilyl groups. End-capped columns have much lower residual silanol group activity compared to non-endcapped columns.^[1] Endcapped columns show decreased retention for hydrogen bond acceptors, such as ionized bases, and increased retention for protonated bases.^[2]

References

1. Méndez A, Bosch E, Rosés M, Neue UD (31 January 2003). "Comparison of the acidity of residual silanol groups in several liquid chromatography columns". Journal of Chromatography. 986 (1): 33–44. doi:10.1016/S0021-9673(02)01899-X. PMID 12585320.
2. Wilson NS, Gilroy J, Dolan JW, Snyder LR (13 February 2004). "Column selectivity in reversed-phase liquid chromatography: VI. Columns with embedded or end-capping polar groups". Journal of Chromatography. 1026 (1–2): 91–100. doi:10.1016/j.chroma.2003.11.041. PMID 14763736.