Zorbax Extend

Fornal et al. [75] determined selectivity differences for bases in RP-HPLC under high pH conditions. They used quantitative structure retention relationships (QSRR) to model retention behavior. They reported that the stability of the columns they used (Waters XTerra MS, Zorbax Extend, Thermo BetaBasic) was limited with... 

SunFire Zorbax Extend Hypersil GOLD Platinum EPS RP-WeX Ascentis Phenyl... 

Better resolution is achieved, especially in the first part of the chromatogram. The last apolar peak is slightly delayed by the polar CN material, but this small increase in run time is a price worth paying. Moreover, we have been able to separate tricyclic antidepressants and their metabolites (a total of 12 peaks) in one isocratic run using Zorbax Bonus/Chromolith Performance and AQUA/ Zorbax Extend coupled in series. 

One works with an alkaline eluent for this and therefore has to use an alkah-resistant phase, e.g., Gemini, Zorbax Extend, XBridge, Asahipak, ZircChrom, Hypercarb. 

In the case of pure RP interactions (e.g., a difference of only an additional CH2 group, methylene group selectivity ), the stationary phase is largely unimportant. The choice of the column is of secondary importance. Therefore, one obtains only a small difference in the separation factors between Zorbax Bonus and Zorbax Extend, which are two completely different phases. If the analyte has polar groups, as in the case of hydroxybenzoates, a differentiation of columns is more easily possible and the separation factors cover a wider range. In the case of triphenylene/o-terphenyl (additional steric effect), the range is even wider. If the polar phase can display its capacity for polar interactions, a better selectivity is observed in all cases. If the difference is only a shorter alkyl chain, as in the case of Zorbax SB Cg, then no distinct positive influences are observed. 

Zorbax Extend, Nucleosil HD, XTerra MS, and Purospher Star (Chem. 24). Hypercarb (Graphite), Nucleosil 50 (high coverage together with a small pore diameter), and Fluofix INW and lEW (short alkyl chains with fluorine atoms) are oddities . 

Symmetry Shield Aqua Zorbax Extend Synergi MAX RP... 

It would be optimal to have in addition one phase with a small pore diameter (e.g., NovaPak, Nucleosil 50) and one with a large pore diameter (e.g., Zorbax SB 300, Jupiter). If one anticipates a need for separations in alkaline media, one should consider XBridge/XTerra, Gemini, Zorbax Extend, Pathfinder, or perhaps also a Hypercarb, a zirconium dioxide or a polymer phase. 

Zorbax SB Cjg/300, Zorbax Edipse XDB, Zorbax ODS, Zorbax SB Cg, Zorbax Bonus (Zorbax SB AQ, in alkaline pH Zorbax Extend)... 

Zorbax Extend Cjg EXT Agilent Bidentate bonding (Cig) 150x4.6 I.D. 5... 

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