As Gas Chromatography separates on the basis of volatility and water is not volatile at normal temperatures so GC is suitable for aqueous phase or not?
Generally no. It depends on your molecule of interest and whether it is volatile and detectable. Most molecules are soluble in water and thus use liquid chromatography (example HPLC) as a means of separation and detection.
Water samples have been injected into a GC equipped with wax column. But, we are talking about 1 uL and only 1 injection and not hundreds of injections (100 uL each). If your molecules are dissolved in water I would strongly suggest HPLC that is equipped with an MS detector.
Yes. You can analyse liquid samplea! Even crude oil can be directly analyzed (check SIMDIS method).
@Anurag take first book on GC!
Regards
GB
If you perform a liquid-liquid extraction of the water sample with Hexane and inject the hexane layer you might.
It sounds like you are asking whether it is possible to use a GC like an LC. No. As others have said it is possible to inject water based samples or use some sort of automated sample prep like head space.
Anurag,
Most GC Columns are not amenable to water -albeit we do use a Carbowax column with a H2O solvent rinse to measure residual Methanol and Ethanol, but run isothermally at 50C, so way below the BP of H2O.-Paul D. Dodson
Not conventionally, but possible if you absolutely have to? I tend to lyophilize aqueous samples and then redissolve in ACN. For high-throughput analysis, move towards LC-MS I would say..
You're probably going to experience issues obtaining reproducible data. If you can, change the solvent (aqueous being water) of your sample to be suitable for GC. I'm not sure what type of column your GC has, but if its not AQUAWAX column or something similar, wouldn't go through with it. Don't want your column breaking down.
Yes, it is possible, but after drying the extract with the drying process ( lyophilization) , then the powder is dissolved in a solvent DMSO
Gas Chromatography is suitable for aqueous phase, but there are a number of limitations. Do not inject water into a packed or capillary column with hydrophilic sorbents: silica gel, zeolite, alumina et al. In the case of capillary columns, the sample volume should be no more than 0.5 μl. Most modern quartz capillary columns are suitable for the analysis of water if a flame ionization detector is used. Do not inject water when using photo-ionization, electron-capture and some other detectors.
I do not agree to Mr. Darbinyan. Water can be injected on GC-FID systems with most types of capillary columns. Furthermore a simple LLE-step (liquid-liquid-extraction) with e.g n-hexane as solvent makes most organic substances in aqueous solutions available for every type of GC instrumentation.
Relatively all the commentators give good response. HPLC is the most suitable chromatographic technique for analyzing aqueous samples. Direct injection of water-containing sample into the GC column will lead to bleeding and destruction of the expensive column. Water can also react with the components of the instrument including detector resulting to their damage. Hence, the best way to analyse an aqueous sample in GC is to dry it either through lyophilization or other promising methods and dissolves it in an organic solvent for GC analysis.
Porapak packed columns can be used in gas chromatography for aqueous samples
GC can be used for aqueous samples. Be very careful with polar columns like Carbowax ( PEG Columns). Reduce the sample quantity. If you are using a TCD, you can get a water peak. FID will not respond to water, so if water is the solvent in your sample, you will not get a solvent peak. If you are using FID, keep a high temperature for the detector to avoid accumulation of water vapour. Otherwise the flame may be put off.
Split splitless, DB1, FID, no problem. Start everything hot enough to vaporize the water.
I agree Oleg Vasilievich Rodinkov.
Gas Chromatography is suitable for aqueous phase, but there are a number of limitations. Do not inject water into a packed or capillary column with hydrophilic sorbents: silica gel, zeolite, alumina et al. In the case of capillary columns, the sample volume should be no more than 0.5 μl. Most modern quartz capillary columns are suitable for the analysis of water if a flame ionization detector is used. Do not inject water when using photo-ionization, electron-capture and some other detectors.