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GC Capillary Columns


 
 
Choosing the Right Phase for Your Separation
So how can you use this elaborate explanation of phases and bonding types?
The answer is simple in resolving complex mixtures and a "one-phase fits all" is more a hope than a reality . Here a polarity scale to assist the chromatographer to choose the best combination of phases which provide an orthogonal solution rather than a simple variation of a theme. Take for example the separation of aromatics on the polyethylene glycol capillary column BP20 (H-bonding) compared to BP1 where the primar y interaction is Van der Waals. Whereas para- and meta-xylene are unresolved on BP1, they are clearly resolved on BP20 with a corresponding change in elution order to the alkanes. This is an interesting
interaction because the aromatic xylenes ha ve been attracted by the H-bond rich BP20. It is not a totally 'one or the other' situation when judging the contribution of H-bond and p-bond affinities, because they have some affinity for each other. A higher component separation is demonstrated with a series of hydrocarbons run on a relatively non-polar phase (BPX5, on the x-axis in figure above right) and on a highly polar
 
BPX90 with the retention times plotted on the y-axis. If the hydrocarbon family is split up on the basis of unsaturated groups, this extra dimension shown in color (chemical group) reveals that the plot shows strong correlations for retention characteristics and functional chemistry.

In this case, the hydrocarbon alkanes (light blue) are completely non-polar. They are retained on the phase only because the phase has sufficient non-polar character to interact with them. In the case of BPX90, it is so polar that it does not offer alkanes the opportunity for interaction. As a result, the alkanes tend to elute almost unretained. The alkanes show almost perfect orthogonality here. Retention on BPX5 versus no retention on BPX90 - they lie almost along the x-axis. We can now reason that if pure hydrocarbons (Van der Waals or non-polar interactions) give little or no BPX90 retention mechanism.
 
In conclusion, polar phases offer selectivity based on functionality rather than on Van der Waals interactions and are an ideal choice for the separation of analytes that were unresolved on non-polar or moderately polar phases.
 
 
The primary advantages of considering phase selectivity include:
  • 2D GC - the choice of orthogonal chemistries f or the 1st and 2nd dimensions.
  • Ubiquitous FAMEs methods.
  • Fast GC - highly retained analytes on non-polar phases elute much earlier on polar phases.
  • Separation of unresolved analytes due to alternative functionality
 
SGE GC Capillary Column Phase Cross Reference Table
SGE Phase Description Capillary Column to Replace
BP1 100% Dimethyl Polysiloxane DB-1, HP-1, Ultra-1, SPB-1, CP-Sil, SCB, RSL-150, RSL-160, Rtx -1, ZB-1, ® CB-1, OV -1, PE-1, 007-1(MS), SP-2100, SE-30, RH-1, CC-1, CP-Sil SCB MS, VF-1ms, P etrocol DH
BP1-PONA 100% Dimethyl Polysiloxane Petrocol DH, DB-Petro
BPX1 100% Dimethyl Polysiloxane DB-HT Sim Dis, DB-2887, Rtx-2887, HP-1, P etrocol 2887, Petrocol EX2887
SolGel-1ms™ SolGel + 100% Dimethyl Polysiloxane Unique highly inert phase
BP5 5% Phenyl Polysiloxane DB-5, DB-5.625, Rtx-5, HP-5, Ultra-2, PTE-5, PB-5, MDN-5, CP-Sil 8CB, VB-5 & ZB-5
BPX5 5% Phenyl Polysilphenylene-siloxane DB-5, DB-5ms, HP-5, Ultra-2, Rtx -5, Rtx-5Sil MS, Rtx 5MS, A T -5, A T -5MS, ® 007-5MS, SPB-5, CP-Sil 8CB, VF-5MS, RSL-200, CB-5, O V -5, PE-5, 007-2(MPS-5), SE-52, SE-54, XTI-5, PTE-5, CC-5, RH-5ms, ZB-5
BPX35 35% Phenyl Polysilphenylene-siloxane DB-35, DB-35ms, Rtx-35, HP-35, HP-35MS, SPB-35, MDN-35, VB-50, ZB-35
BPX608 35% Phenyl Polysilphenylene-siloxane DB-608, Rtx-35, SPB-608
BPX50 50% OV-17, SP-2250, DB-17ms, DB-17ht, Rtx-50, SPB-50, HP-50+, HP-17, VB-50/608, ZB-50
HT5 5% Phenyl Polysilphenylene-siloxane MXT -1 SimDist, HT -SimDist, DistCB, MXT -500
HT8 8%Phenyl Polysilphenylene-siloxane No equivlent, unique high temperature capillary column with special selectivity (standard for PCB)
BP225 50% Cyanopropylphenyl Polysiloxane HP-225, DB-225, Rtx-225
BP10(1701) 14% Cyanopropylphenyl Polysiloxane DB-1701, Rtx-1701, HP-1701, SPB-7, CP-Sil 19CB, VB-1701, ZB-1701
BP624, BPX-Volatiles Cyanopropylphenyl Polysiloxane DB-624, HP-VOC,, Rtx Volatiles, Rtx 624, VOCOL, VB-624, ZB-624
BPX70 70% Cyanopropyl Polysilphenylene-silxone DB-23, CP-Sil 88, VF-23ms, SP-2330, SP2380, Rtx -2330, 007-23, A T -Silar, PE-23
BPX90 90% Cyanopropyl Polysilphenylene-silxone Unique highly polar phase
BP21 (FFAP) Polyethylene Glycol (TP A treated) DB-FFAP , HP-FF AP , Stabilwax-DA, CP Wax 58CB, VB-FFAP , ZB-FF AP
BP20 (Wax)™ Polyethylene Glycol DB-Wax, Rtx-Wax, Stabilwax, HP20M, HP-Wax, HP-INNOWax, Supelcowax-10, A T -Wax, Nukol, CP Wax 2CB, VB-WAX, ZB-WAX
SolGel-Wax™ SolGel + Polyethylene Glycol Unique highly inert phase
CYDEX-B Permethylated Beta Cyclodextrin Cyclodex-B, Rt-BDEXM
 
 
 
 
 

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