High-performance liquid chromatography (HPLC) and gas chromatography (GC) is a multipurpose and very well accepted chromatographic technique utilized for the separation of complex mixtures. HPLC and GC techniques used for identification and quantification purpose but for different intend as its function and application is different.
HPLC and GC is based on the principle where compound subjected on the surface or within a solid or liquid stationary phase by isolating it with the help of the mobile phase.
|Principal||Separation of sample is accomplished by solid stationary phase and liquid mobile phase.||Separation of sample is accomplished by liquid or solid stationary phase and gaseous mobile phase.|
|Temperature Control||Temp. control approach is not necessary or not required. Generally ambient temp. is required.||Temp. control is much more important as the column is placed inside the oven with control temp. program. Generally higher temp. required for analysis.|
|Sample State||Separation of liquid state any soluble samples usually with higher molecular weight.||Separation of volatile and thermally stable samples with low molecular weight.|
|Column||Column are generally shorter and broader diameter.||Columns are long, normally 10 to 60 meters in length and narrow diameter.|
|Column Types||Octadecylsilane, Octyl silane, Hexyl, Trimethyl Silyl, Amino, Cyano, TMS, Silica, Hillic, Diol, Ion exchange, Chiral, Phenyl, Gel permeation & Size exclusion chromatography||WCOT, SCOT, PLOT, Carbowax, Polyethylene glycol, Dimethyl polysiloxane, Phenyl methyl polysiloxane, High molecular mass esters, Amides, Hydrocarbons, Polyaromatic compound, Cyanopropyl polysiloxane|
|Separation||Separation based on the interaction of sample with mobile and stationary phases.||Separation based on the boiling point of sample.|
|Resolution Issues||Samples with identical polarity||Samples with similar molecular weight|
|Mobile Phase||Liquids, e.g. Polar solvents like water, acetonitrile, methanol, etc. Non polar solvents like Hexane, Heptane, isopropyl alcohol, dichloromethane etc.||Gases, e.g. Nitrogen, Helium, Argon, Hydrogen, Oxygen|
|Speed||Analysis speed is slow.||Analysis speed is fast|
|Peak shape||Generally, detect bigger or wider peaks which effect lower resolution.||Relatively sharp peaks observed with good resolution.|
|Detectors||UV-Visible detector, Photodiode-array detection, Refractive index detector, light scattering detector, Charged aerosol detector, Conductivity detector, Fluorescence detector, Chemiluminescence detector,|
Optical rotation detector, Mass spectrometric, IR Detector etc.
|GC detectors are sensitive and selective, e.g. Flame ionization detector (FID), Thermal conductivity detector (TCD), Electrochemical detector, Electron capture detector, Nitrogen phosphorous detector, Flame photometric detector, Electrolytic conductivity detector, Mass spectrometric, Photo Ionization detector, Reduction gas detector, Catalytic combustion detector, Helium ionization detector etc.|
|Cost||Less costly||High cost|
The selection of instrument is purely based on the nature of sample and requirement of sample.