Understanding the Capillary GC Column

1 Understanding the Capillary GC ColumnMark SInnottApplication EngineerThings to Is it Volatile enough to chromatograph by GC? Is it stable enough to survive vaporization? Is it a Gas or a Liquid? How are we getting the Sample Injected? What is the sample Matrix? Can we do sample clean up? Is it an established method?--EPA, ASTM, USP What do we Know about the analytes? What else MAY be present in the sample?Group/Presentation TitleAgilent RestrictedPage 2 Group/Presentation TitleAgilent RestrictedPage 3 Capillary Column TYPESL iquid PhaseCarrier GasPorous Layer Open Tube (PLOT)Wall Coated Open Tube (WCOT)

2 Solid ParticlesCarrier GasGroup/Presentation TitleAgilent RestrictedPage 6 STATIONARY PHASE POLYMERSSiRROSiRROSiRRSiRROnmOSiRRnSilox aneSiarylene backboneR=methyl, phenyl, cyanopropyl, trifluoropropylOHCH2CH2O nPolyethylene GlycolGroup/Presentation TitleAgilent RestrictedPage 7 Stationary Phase% Substitution --polysiloxanes% = # of sites on silicon atoms occupiedBalance is methylOSiRRnSiloxaneR=methyl, phenyl, cyanopropyl, trifluoropropylGroup/Presentation TitleAgilent RestrictedPage 8 Stationary PhasePoly(ethylene) Glycol100% PEG (DB-WAX)Less stable than polysiloxanesUnique separation characteristicsHOCH2CH2 OHnGroup/Presentation TitleAgilent RestrictedPage 9 Poly(Ethylene) GlycolModified Base deactivated (CAM) Acid Modified (DB-FFAP) Extended Temperature RangePLOT columns are primarily, but not exclusively, used for the analysis of gases and low boiling point solutes ( , boiling point of solute is at or below room temperature).

3 PLOT Column Types Agilent J&W PLOT columns begin with the designation of GS (Gas Solid) or HP-PLOT followed by a specific name CP (ChromPack) followed by name 10 stationary phases GS-OxyPLOT/ CP-Lowox GS-Alumina HP-PLOT Al2O3 M HP-PLOT Al2O3 S HP-PLOT Al2O3 KCl / CP-AL2O3/KCl HP-PLOT MoleSieve/ CP-Molsieve5A GS-CarbonPLOT/ CP-CarboBOND HP-PLOT Q / CP PoraBONDQ HP-PLOT U / CP-PoraBONDU GS-GasPro/ CP-SilicaPLOT GS-OxyPLOT: oxygenates HP-PLOT Molesieve: O2, N2, CO, Methane HP-PLOT Alumina and GS-Alumina: complex hydrocarbon gas matrices, ethylene and propylene purity, 1,4-butadiene HP-PLOT Q: freons, sulfides HP-PLOT U: C1 to C7 hydrocarbons, CO2, Polar Hydrocarbons GS-GasPro: freons, sulfurs, inorganic gases GS-CarbonPLOT.

4 Inorganic and organic gasesIntegrated Particle Trap PLOT ColumnsGroup/Presentation TitleAgilent RestrictedPage 12 Particle trap is on both ends of the columnOn the front end to help facilitate backflushingwithout blowing particles back into the inlet / valveUltra Inert PhasesGroup/Presentation TitleAgilent RestrictedPage 14DB-1msUIHP-1msUIDB-5msUIHP-5msUIDB-17m sUIDB-624 UIDB-Select 624UI 467DB-WaxUISame Selectivity, more Inertness!Group/Presentation TitleAgilent RestrictedPage 15 Three Types Of Low Bleed Phases Phases tailored to mimic currently existing polymersExamples: DB-5ms, DB-35ms, DB-17ms, VF-1701ms New phases unrelated to any previously existing polymersExamples: DB-XLB Optimized manufacturing processesDB-1ms, HP-1ms, HP-5ms, VF-5msSiRROSiRROSiRRSiRROnmSiarylene backboneGroup/Presentation TitleAgilent RestrictedPage 16 What is Column Bleed?

5 ?? Back Biting Mechanism of Product Formation+RepeatSiSiSiSiSiSiSiOOOOOOOHCH 3CH3CH3CH3CH3CH3CH3CH3CH3CH3CH3CH3CH3CH3 OHSiSiOSiOSiOCH3CH3CH3CH3CH3CH3CH3CH3 SiOOOCH3H3CH3CH3 CSiSiCH3CH3 OOOOOOSiHOH3 CCH3CH3CH3CH3 SiSiSiSiSiSiCH3CH3CH3CH3CH3CH3CH3CH3CH3 Cyclic products are thermodynamically more stable!Group/Presentation TitleAgilent RestrictedPage 17DB-5ms StructureCH3 SiSiSiSiOOOODB-5 StructureDB-55% PhenylSiSiSiSiOODB-5ms to match DB-5 as closely as possibleCH3CH3CH3CH3CH3CH3CH3CH3CH3CH3CH 3CH3 Group/Presentation TitleAgilent RestrictedMonth ##, 200 XDB-35MS VS STANDARD 35% PHENYLB enzo[g,h,i]perylene, 35% PhenylDB-35msGroup/Presentation TitleAgilent RestrictedPage 19 Solid line:DB-5ms 30 m x.

6 25 mm x .25 mmDashed line: DB-5 30 m x .25 mm x .25 mmOven:60oC isothermalCarrier gas: H2at 40 cm/sec1: Ethylbenzene2: m-Xylene3: p-Xylene4: o-XyleneChromatograms are offset on x-axisfor easier viewingDB-5msDB-5 Group/Presentation TitleAgilent RestrictedPage 20k2= partition ratio of 2ndpeakk1= partition ratio of 1stpeakWhy is stationary phase type important?Influence on 12kk RsNkk=411+ - Group/Presentation TitleAgilent RestrictedPage 21 Selectivity Relative spacing of the chromatographic peaks The result of all non-polar, polarizable and polar interactions that cause a stationary phase to be more or less retentive to one analytethan anotherGroup/Presentation TitleAgilent RestrictedPage 22 Optimizing Selectivity ( )

7 Match analyte polarity to stationary phase polarity- like dissolves like Take advantage of unique interactions between analyte and stationary phase functional groupsGroup/Presentation TitleAgilent RestrictedPage 23 AnalytePolarityNonpolar Molecules-generally composed of only carbon and hydrogen and exhibit no dipole moment (Straight-chained hydrocarbons (n-alkanes))Polar Molecules-primarily composed of carbon and hydrogen but also contain atoms of nitrogen, oxygen, phosphorus, sulfur, or a halogen (Alcohols, amines, thiols, ketones, nitriles, organo-halides, etc.)

8 Includes dipole-dipole interactions and H-bonding)Polarizable Molecules-primarily composed of carbon and hydrogen, but also contain unsaturated bonds (Alkenes, alkynes and aromatic compounds)Group/Presentation TitleAgilent RestrictedPage 24 Selectivity Interactions Dispersion Dipole Hydrogen bondingGroup/Presentation TitleAgilent RestrictedPage 26 Dispersion Interaction Solubility And Retention30 m x mm ID, mHe at 35 cm/sec50-170 C at 15 /min100% PEG(polar)100% Methyl(non-polar)C10C12 Hexanol02468 HexanolC10C1202468 Hexanol158oCDecane174oCDodecane216oCGrou p/Presentation TitleAgilent RestrictedPage 27 Dispersion Interaction DHvapVapor pressure : good approximationBoiling point.

9 Poor approximationGroup/Presentation TitleAgilent RestrictedPage 35 SelectivityInteraction StrengthsPhaseDispersionDipoleH BondingMethylStrongNoneNonePhenylStrongN oneWeakCyanopropylStrongVery StrongModerateTrifluoropropylStrongModer ateWeakPEGS trongStrongModerateGroup/Presentation TitleAgilent RestrictedPage 36 PolarityPolarityStabilityTemperature RangeCompounds PropertiesGroup/Presentation TitleAgilent RestrictedPage 38 CompoundStructurePolarAromaticH-BondingD ipoleTolueneNoYesNoInducedHexanolYesNoYe sYesPhenolYesYesYesYesDecaneNoNoNoNoNaph thaleneNoYesNoInducedDodecaneNoNoNoNoGro up/Presentation TitleAgilent RestrictedPage 39100% Methyl PolysiloxaneStrong DispersionNo DipoleNo H Bonding1.

10 Toluene (A-ID) 110oC2. Hexanol (P-H-D) 158oC3. Phenol (P-A-H-D) 181oC4. Decane(C10) 174oC5. Naphthalene (A-D) 218oC6. Dodecane (C12) 216oC0246810121416123456 Group/Presentation TitleAgilent RestrictedPage 405% Phenyl (aromatic phase) Strong DispersionNo DipoleWeak H Bonding02468101214165% Phenyl12345,60246810121416100% Methyl1345621. Toluene (A-ID) 110oC2. Hexanol (P-H-D) 158oC3. Phenol (P-A-H-D) 181oC4. Decane(C10) 174oC5. Naphthalene (A-D) 218oC6. Dodecane (C12) 216oCGroup/Presentation TitleAgilent RestrictedPage 4150% Phenyl (more aromatic)Strong DispersionNo DipoleWeak H Bonding0246810121416100% Methyl13456250% Phenyl10246810121416243651.