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How can I measure Glycerol with GC/FID?
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+ Glycerol
+ Gc-fid
+ Flame ionization
+ Organic chemistry synthesis
+ Organic chemistry
Posted by
Manuel Jimenez
How can I measure Glycerol with GC/FID?
Try to sililate the sample and the model mixtures of both alcohols /with different ratios of ethanol and glycerol/, as well. Perform GLC analysis and use the method of calibration curve for their determination. However, a method of inner standard may serve better /as an IS 1,2 ethandiol or erithritol can be used/. As sililation agent hexamethyl disilazane HMDSA, or chlor-trimethylsilan /TMCS/ could be used. This could work with water free samples. Another method of glycerol determination might be GLC of glycerol triacetate. Dissolve 1ml of the water free sample in 2 ml of pyridine, add the same volume of acetanhydride. Immerse reaction vessel into the water bath of 80 oC for 60 min. After acetylation evaporate pyridine and acetanhydride in stream of N2 /at 80 oC/ and analyse the sample directly. The GLC analysis may be influenced by slight tailing caused by traces of pyridine and anhydide, however.. Use non polar filling for your column like Chromosorb 102, /80 to 100 mesh/.Use direct injecion into the 120 cm column, He or N2 as a carrier gas, and column temperature approx. betwen 80 to 140 oC. Conditions of GLC of sililated and acetylated samples may differ in the column temperature. Do not inject more than 1 - 2 microliters of the sample. It is possible to determine content of glycerol in ethanol also using Refractive index measurements. The method, however is less exact due to possible evaporation of ehanol during analysis. Evaluation of glycerol content can be done using calibration curve. Good luck, R.S.
Try to sililate the sample and the model mixtures of both alcohols /with different ratios of ethanol and glycerol/, as well. Perform GLC analysis and use the method of calibration curve for their determination. However, a method of inner standard may serve better /as an IS 1,2 ethandiol or erithritol can be used/. As sililation agent hexamethyl disilazane HMDSA, or chlor-trimethylsilan /TMCS/ could be used. This could work with water free samples. Another method of glycerol determination might be GLC of glycerol triacetate. Dissolve 1ml of the water free sample in 2 ml of pyridine, add the same volume of acetanhydride. Immerse reaction vessel into the water bath of 80 oC for 60 min. After acetylation evaporate pyridine and acetanhydride in stream of N2 /at 80 oC/ and analyse the sample directly. The GLC analysis may be influenced by slight tailing caused by traces of pyridine and anhydide, however.. Use non polar filling for your column like Chromosorb 102, /80 to 100 mesh/.Use direct injecion into the 120 cm column, He or N2 as a carrier gas, and column temperature approx. betwen 80 to 140 oC. Conditions of GLC of sililated and acetylated samples may differ in the column temperature. Do not inject more than 1 - 2 microliters of the sample. It is possible to determine content of glycerol in ethanol also using Refractive index measurements. The method, however is less exact due to possible evaporation of ehanol during analysis. Evaluation of glycerol content can be done using calibration curve. Good luck, R.S.
Try to sililate the sample and the model mixtures of both alcohols /with different ratios of ethanol and glycerol/, as well. Perform GLC analysis and use the method of calibration curve for their determination. However, a method of inner standard may serve better /as an IS 1,2 ethandiol or erithritol can be used/.
As sililation agent hexamethyl disilazane HMDSA, or chlor-trimethylsilan /TMCS/ could be used. This could work with water free samples.
Another method of glycerol determination might be GLC of glycerol triacetate. Dissolve 1ml of the water free sample in 2 ml of pyridine, add the same volume of acetanhydride. Immerse reaction vessel into the water bath of 80 oC for 60 min. After acetylation evaporate pyridine and acetanhydride in stream of N2 /at 80 oC/ and analyse the sample directly. The GLC analysis may be influenced by slight tailing caused by traces of pyridine and anhydide, however..
Use non polar filling for your column like Chromosorb 102, /80 to 100 mesh/.Use direct injecion into the 120 cm column, He or N2 as a carrier gas, and column temperature approx. betwen 80 to 140 oC. Conditions of GLC of sililated and acetylated samples may differ in the column temperature. Do not inject more than 1 - 2 microliters of the sample.
It is possible to determine content of glycerol in ethanol also using Refractive index measurements. The method, however is less exact due to possible evaporation of ehanol during analysis. Evaluation of glycerol content can be done using calibration curve.
Good luck,
R.S.
Try to sililate the sample and the model mixtures of both alcohols /with different ratios of ethanol and glycerol/, as well. Perform GLC analysis and use the method of calibration curve for their determination. However, a method of inner standard may serve better /as an IS 1,2 ethandiol or erithritol can be used/.
As sililation agent hexamethyl disilazane HMDSA, or chlor-trimethylsilan /TMCS/ could be used. This could work with water free samples.
Another method of glycerol determination might be GLC of glycerol triacetate. Dissolve 1ml of the water free sample in 2 ml of pyridine, add the same volume of acetanhydride. Immerse reaction vessel into the water bath of 80 oC for 60 min. After acetylation evaporate pyridine and acetanhydride in stream of N2 /at 80 oC/ and analyse the sample directly. The GLC analysis may be influenced by slight tailing caused by traces of pyridine and anhydide, however..
Use non polar filling for your column like Chromosorb 102, /80 to 100 mesh/.Use direct injecion into the 120 cm column, He or N2 as a carrier gas, and column temperature approx. betwen 80 to 140 oC. Conditions of GLC of sililated and acetylated samples may differ in the column temperature. Do not inject more than 1 - 2 microliters of the sample.
It is possible to determine content of glycerol in ethanol also using Refractive index measurements. The method, however is less exact due to possible evaporation of ehanol during analysis. Evaluation of glycerol content can be done using calibration curve.
Good luck,
R.S.
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