Chromatography - Bartelt

ChromatographyChromatography columns/HPLCVarioPrep preparative columns NUCLEODUR ® C18 Gravityparticle size 10µm, 18% CLLG CHROMATOGRAPHY CATALOGUEMACHEREY-NAGELInt.Length PK Cat. No.diam.mmmm40.0 250 1 4.004 782NUCLEODUR ® C18 Isis phase with high steric selectivityC18 phase with special polymeric, crosslinked surface modification - USP L1pore size 110 Å, particle sizes 1.8µm, 3µm and 5µm; 20%Chigh steric selectivityoutstanding surface deactivationsuitable for LC/MS due low bleeding characteristicspH stability 1 - 10broad range of application: steroids, (o,p,m-) substituted aromatics, fat-soluble vitaminsMACHEREY-NAGELSurface modificationBy use of specific C 18 silanes and appropriate polymeric bonding technologiesa dense shield of alkyl chains protects the subjacent silica matrix.Elemental analysis of NUCLEODUR ® C 18 Isis shows a carbon load of 20%.The target crosslinking of the C 18 chains on the surface enables the separationof compounds with similar molecular structure but different stereochemicalproperties. The technical term for this feature is steric selectivity.Steric selectivity of NUCLEODUR ® C 18 IsisColumns: 125 x 4 mm; NUCLEODUR ® C 18 Isis, monomericallycoated C 18 phase, C 18 phase with polar endcappingEluent:methanol – water (90:10, v/v)Flow rate: 1 ml/min, temperature 35 °CDetection: UV, 254 nmInjection volume: 5 μlPeaks:1. o-Terphenyl22. m-Terphenyl3. p-Terphenyl144. Triphenylene3C 18 , polar endcappingThe separation of o-terphenyl and triphenylene is a concrete example toevaluate the selectivity potential of a reversed phase column in terms ofthe different shape of two molecules. The phenyl rings of o-terphenyl aretwisted out of plane while triphenylene has a planar geometry.The separation factor (α value) is a measure for the steric selectivity. As isshown in the following chromatograms the α value is considerable larger onNUCLEODUR ® C 18 Isis compared to a conventional C 18 column.Steric selectivity of NUCLEODUR ® C 18 IsisColumns 125 x 4 mm; eluent methanol – water (80:20, v/v)Flow rate: 1 ml/min, temperature 40 °CDetection: UV, 254 nm, injection volume 1 μlPeaks: 1. o-Terphenyl, 2. Triphenylenemonomericallycoated C 18 phase12NUCLEODUR ®C 18 Isis12monomeric C 18C 18 Isis0 1 2 3 4 min 5= 1.350 5 10= 1.930 5 10 minEC analytical columns NUCLEODUR ® C18 Isis, 1.8µmparticle size 1.8µm, 20% CMACHEREY-NAGELInt.diam.mm2.03.04.04.62.03.04.04.62.0Length PK Cat. No.mm30303030505050501001111111114.004 5014.004 5024.004 5034.004 5044.004 4974.004 4984.004 4994.004 5004.006 01962E & OE.