Actually my sample contains contains glycerol and water. There is a problem with the analysis with the sample in GC with FID detector because of the presence of water. Is it possible to analyze the mixture of glycerol and water in GC with TCD detector? I want to use nitrogen as a carrier gas.
Dear Sujoy,
You could use Standard methods ASTM D6584 or EN 14105 measure the free and total glycerin in B100 biodiesel. The condition is:
column:
MET-Biodiesel, 14 m x 0.53 mm I.D., 0.16 μm with integrated
2 m x 0.53 mm I.D. guard (28668-U)
oven:50 °C (1 min.), 15 °C/min. to 180 °C, 7 °C/min. to 230 °C, 30 °C/min.
to 380 °C (10 min.)
det.:FID, 380 °C
carrier gas:helium, 3.0 mL/min.
injection:1 μL, cold on-column
sample:B100 Biodiesel plus Butanetriol Internal Standard (44896-U) and
Tricaprin Internal Standard (44897-U), privatized with MSTFA
(394866) then diluted in heptane
e
Sujoy,
As with any such question, the simple answer is yes, a TCD can detect both materials using nitrogen as the carrier gas.
However,
The nature of the sample, the required levels of detection and the context of the analysis (research scouting, qc service lab, certified analysis, or process control lab or process control instrument) are key issues which need to be considered before deciding a specific assay. By assay I mean the sample preparation procedure, choice of gc conditions (column, temperature(s),an so on.
Sampling and sample preparation can be very important. For example: At very high water levels and low diol or polyol levels (i.e, .a hydrophilic sample matrix) a polar solvent such as THF, acetonitrile, etc, is preferable, whereas at low analyte levels in a lipophilic sample like a biodiesel, a non polar solvent such as an alkane is often more worthwhile. If these considerations are not taken into account, unreliable results can be obtained, no matter what the rest of the choices of instrument or chromatographic conditions.
Dear Scot,
I like to say thanks for your valuable opinion. But I want to use porapak Q column. The maximum operating temperature 250 C. But the glycerol boiling point is 290 C. Is it possible to detect glycerol with this column?
I am agree with Scott. TCD will be the best detector, because it detects water. If you use a FID detector you will be able to detect only the glycerol. FID detector doesn't detect water.
Dear Alberto and Scot,
Please suggest me one GC program for analysis of glycerol and water mixture with TCD detector. I like to use Porapak Q column and nitrogen as a carrier gas.
Sorry, I want to ask a question related to glycerol and water.
I am trying to quantify glycerol by Gas Chromatography. The results are not trustworthy. I know that there is water in the mixture, and I am using a polar column (CP-WAX 52 CB). Can the water interfere in the measure?
Thank you very much!
Dear Federico,
If you want to quantify the glycerol amount, then you have to use Wax column with high temperature range and FID detector in GC. Water will not interfere in the analysis. But one thing you have to take in your mind that you have to inject very less amount around 0.1 microliter or less.
The other question that comes to mind: Why use GC at all? What is in the mixture? Is it a simple 2 component mix and the goal is quantitation of the composition? If so, need not use GC at all. ATR IR is fine for such a problem. Quick, simple cheap. HPLC is another route (ri detector)
Hello all,
Please I would like to know the best column you can use for GC-FID analysis of liquid products from glycerol steam reforming?
Thank you,
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