Equation for calculating surface coverage from end-capping of chromatographic bonded phases

Authors
Citation
Je. Sandoval, Equation for calculating surface coverage from end-capping of chromatographic bonded phases, J CHROMAT A, 852(2), 1999, pp. 375-381
Citations number
16
Language
INGLESE
art.tipo
Article
Categorie Soggetti
Chemistry & Analysis","Spectroscopy /Instrumentation/Analytical Sciences
Journal title
JOURNAL OF CHROMATOGRAPHY A
ISSN journal
0021-9673 → ACNP
Volume
852
Issue
2
Year of publication
1999
Pages
375 - 381
Database
ISI
SICI code
0021-9673(19990813)852:2<375:EFCSCF>2.0.ZU;2-K
Abstract
An equation was derived to calculate the surface density of trimethylsilyl groups (alpha(TMS)) on bonded chromatographic stationary phases that have u ndergone primary as well as secondary ('end-capping') chemical modification . The new equation is an extension of that published by Berendsen-de Galan for calculating primary surface coverage and, likewise, alpha(TMS) is calcu lated in terms of the carbon content (% by weight) of the bonded material b efore and after end-capping, specific surface area of the starting silica a nd structural information (molecular weight and number of carbon atoms) of the anchored groups. The new equation is valuable when a thorough character ization of bonded stationary phases is desirable and, if used along with th e Berendsen-de Galan equation, it affords total ligand coverage information . Application of the new equation to correct for measurable carbon content of the starting support leads to a more accurate expression for surface cov erage from primary as well as secondary bonding. The scope and limitations of the new equation are discussed. (C) 1999 Elsevier Science B.V. All right s reserved.