GCGC

Schematic of a GCSchematic of a GC

Typical GCTypical GC

Carrier gas/Carrier gas/RegulatorRegulator

Varian 3350 Gas Varian 3350 Gas ChromatographChromatograph

Computer Controls forComputer Controls forMethod and Output Method and Output

SeparationSeparation

T=0

T=10’

T=20’

InjectorInjector DetectorDetector

MostMost Interaction with Stationary PhaseInteraction with Stationary Phase LeastLeast

Flow of Mobile PhaseFlow of Mobile Phase

GC – Peak BroadeningGC – Peak Broadening

Carrier gas velocity in the column

Chromatography – Dead Volume MixingChromatography – Dead Volume Mixing

GC - ColumnGC - Column

ColumnsColumns

GC – Capillary ColumnGC – Capillary Column

SeparationSeparation

GC Liquid Phases

GC – Column EfficiencyGC – Column Efficiency

Packed Capillary

GC – Sample Capacity EffectGC – Sample Capacity Effect

0.25 mm 0.53 mm

GC – Column FlowsGC – Column Flows

GC – Column PerformanceGC – Column Performance

GC – Film Thickness EffectGC – Film Thickness Effect

0.25m

1.0m

3.0m

5.0m

GC – Isothermal and ProgrammingGC – Isothermal and Programming

1050C 500C

500C 3minTo 1400C at100C/min

Mobile PhaseMobile Phase

GC – Gases PropertiesGC – Gases Properties

GC – van Deemter Plots/CurvesGC – van Deemter Plots/Curves

N2

He

H2

GC - InjectorsGC - Injectors

GCGCCapillaryCapillaryInjection Injection

ModesModes

GC – Injector InsertsGC – Injector Inserts

GC – Injector Linear & Repeatability of Peak AreaGC – Injector Linear & Repeatability of Peak Area

GC - InjectorsGC - Injectors

SPLIT INJECTORAdvantage - Limitations Injected zone narrow Small sample aliquot avoids overloading Mass discrimination of sample components (different range of volatility) Systematic errors for quantitative analysis In trace analysis: only part of analytes to detector

GC- InjectorsGC- Injectors

SPLITLESS INJECTOR Advantage - Limitations Avoids large tailing of solvent peak Allows transfer of main part of sample components into detector Trace analysis: favourable technique for

insertion of diluted samples Recondensation of solvent at top of capillary:

possible damaging stationary phase Only columns with chemically bonded phases Necessary wettability of stationary phase for

condensed solvent (droplets)

Injection Technique and Peak DiscriminationInjection Technique and Peak Discrimination

Filled Needle

Hot Needle

Cold On-Column

GC – Injector Solvent Vapours Volume GC – Injector Solvent Vapours Volume

GC – On-Column InjectorGC – On-Column Injector

GC - InjectorsGC - Injectors

Advantage of on-column injector: avoids mass discrimination effects

trace analysis: enables quantitative insertion of sample into column (and detector)

labile components not stressed thermally

GC - DetectorsGC - Detectors

GC - FID

GC – Flame Ionization Detector (FID)GC – Flame Ionization Detector (FID)

GC – FID Response to Gases FlowsGC – FID Response to Gases Flows

GC – Alkali Ionization Detector (N,P)GC – Alkali Ionization Detector (N,P)

GC – FID & AFID ResponseGC – FID & AFID Response

GC – Electron Capture Detector (ECD)GC – Electron Capture Detector (ECD)

GC - Thermal Conductivity Detector

GC – Atomic Emission DetectorGC – Atomic Emission Detector

GC – Detectors PerformanceGC – Detectors Performance

GC – IR – Detector Gas CellGC – IR – Detector Gas Cell

Peak Area IntegrationPeak Area IntegrationQualitative and QuantitativeQualitative and Quantitative

Chromatography – Sampling Rate and AccuracyChromatography – Sampling Rate and Accuracy

2 Hz

25 Hz

Chromatography – Integration ProblemsChromatography – Integration Problems

GC – Integration Problems - DeconvolutionGC – Integration Problems - Deconvolution

Kovatc’s IndexKovatc’s Index

GC – Retention IndexesGC – Retention Indexes

GC – Derivatization ReagentsGC – Derivatization Reagents

Marine Source Animal Source

Fatty Acids

Conditions Column: SP-2560, 100m x 0.25mm ID, 0.20µm filmCat. No.: 24056Oven: 140°C (5 min) to 240°C at 4°C/min, hold 15 minCarrier: helium, 20cm/sec, 175°CDet.: FID, 260°CInj.: 1µL Supelco 37 Component FAME Mix (10mg/mL total), split (100:1), 250°C

List of components on the next slide

Components for SP 2560 ChromatogramComponents for SP 2560 ChromatogramAnalyte DataAnalyte Data Component (acid methyl Component (acid methyl

ester) Weight (%)ester) Weight (%)1. C4:0 (Butryic) 41. C4:0 (Butryic) 42. C6:0 (Caproic) 42. C6:0 (Caproic) 43. C8:0 (Caprylic) 43. C8:0 (Caprylic) 44. C10:0 (Capric) 44. C10:0 (Capric) 45. C11:0 (Undecanoic) 25. C11:0 (Undecanoic) 26. C12:0 (Lauric) 46. C12:0 (Lauric) 47. C13:0 (Tridecanoic) 27. C13:0 (Tridecanoic) 28. C14:0 (Myristic) 48. C14:0 (Myristic) 49. C14:1 (Myristoleic) 29. C14:1 (Myristoleic) 210. C15:0 (Pentadecanoic) 210. C15:0 (Pentadecanoic) 211. C15:1 11. C15:1 (cis(cis-10-Pentadecenoic) 2-10-Pentadecenoic) 212. C16:0 (Palmitic) 612. C16:0 (Palmitic) 613. C16:1 (Palmitoleic) 213. C16:1 (Palmitoleic) 214. C17:0 (Heptadecanoic) 214. C17:0 (Heptadecanoic) 215. C17:1 15. C17:1 (cis(cis-10-Heptadecenoic) 2-10-Heptadecenoic) 216. C18:0 (Stearic) 416. C18:0 (Stearic) 417. C18:1n9c (Oleic) 417. C18:1n9c (Oleic) 418. C18:1n9t (Elaidic) 218. C18:1n9t (Elaidic) 219. C18:2n6c (Linoleic)19. C18:2n6c (Linoleic) 2 2

20. C18:2n6t (Linolelaidic) 220. C18:2n6t (Linolelaidic) 221. C18:3n6 (g-Linolenic) 221. C18:3n6 (g-Linolenic) 222. C18:3n3 (a-Linolenic) 222. C18:3n3 (a-Linolenic) 223. C20:0 (Arachidic) 423. C20:0 (Arachidic) 424. C20:1n9 24. C20:1n9 (cis(cis-11-Eicosenoic) 2-11-Eicosenoic) 225. C20:2 25. C20:2 (cis(cis-11,14-Eicosadienoic) 2-11,14-Eicosadienoic) 226. C20:3n6 26. C20:3n6 (cis(cis-8,11,14-Eicosatrienoic) 2-8,11,14-Eicosatrienoic) 227. C20:3n3 27. C20:3n3 (cis(cis-11,14,17-Eicosatrienoic) 2-11,14,17-Eicosatrienoic) 228. C20:4n6 (Arachidonic) 228. C20:4n6 (Arachidonic) 229. C20:5n3 29. C20:5n3 (cis(cis-5,8,11,14,17-Eicosapentaenoic) 2-5,8,11,14,17-Eicosapentaenoic) 230. C21:0 (Henicosanoic) 230. C21:0 (Henicosanoic) 231. C22:0 (Behenic) 431. C22:0 (Behenic) 432. C22:1n9 (Erucic) 232. C22:1n9 (Erucic) 233. C22:233. C22:2 (cis (cis-13,16-Docosadienoic) 2-13,16-Docosadienoic) 234. C22:6n334. C22:6n3 (cis(cis-4,7,10,13,16,19-Docosahexaenoic) 2-4,7,10,13,16,19-Docosahexaenoic) 235. C23:0 (Tricosanoic) 235. C23:0 (Tricosanoic) 236. C24:0 (Lignoceric) 436. C24:0 (Lignoceric) 437. C24:1n9 (Nervonic) 237. C24:1n9 (Nervonic) 2