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.{{cite journal |vauthors=Méndez A, Bosch E, Rosés M, Neue UD |date=31 January 2003 |title=Comparison of the acidity of residual silanol groups in several liquid chromatography columns |journal=Journal of Chromatography |volume=986 |issue=1 |pages=33–44 |doi=10.1016/S0021-9673(02)01899-X |pmid=12585320 }} Endcapped columns show decreased retention for hydrogen bond acceptors, such as ionized bases, and increased retention for protonated bases.{{cite journal |vauthors=Wilson NS, Gilroy J, Dolan JW, Snyder LR |date=13 February 2004 |title=Column selectivity in reversed-phase liquid chromatography: VI. Columns with embedded or end-capping polar groups |journal=Journal of Chromatography |volume=1026 |issue=1–2 |pages=91–100 |doi=10.1016/j.chroma.2003.11.041 |pmid=14763736 }}