Chromatography Forum

Hello

I usually use pure water in calibration standards when I making the calibration curve. The water conductivity is always 0,05 µS/cm (18,18 µΩ-1 cm-1).

I had a problem with the conductivity sensor, and I used water with conductivity next to 3 µS/cm. I don't know if the peak's areas are changing because of that or if it's just a coincidence.

Could you help me, please?

The detector is FID.

Thank you

I don't know if the FID would detect the difference in the water conductivity, but would the standards themselves be affected? Difference in solubility?

If the background is higher because of an organic contaminate in the water then maybe it would raise the baseline and cause the peaks to be smaller.

What are your target analytes?

I don't know if the FID would detect the difference in the water conductivity, but would the standards themselves be affected? Difference in solubility?

If the background is higher because of an organic contaminate in the water then maybe it would raise the baseline and cause the peaks to be smaller.

What are your target analytes?

The analytes are:
acetaldehyde
ethyl acetate
methanol
1-propanol
2-methyl-1-propanol
1-buthanol
2-methyl-1-buthanol
3-methyl-1-buthanol
furfural
internal stardart: 4-methyl-2-pentanol

Water is solvent which vapor takes most volume than any other solvents.
So part of sample will be purged out with amount of vapor not fit in liner.

Clusterization with H-O-H will change FID response factor of C-C-C... chains in 5th digit after decimal point. Or not at all.
Only MS can prove this.

Water has an expansion volume upon vaporization which is dramatic. This can cause a number of issues if it is used as a solvent/diluent in GC. The gas volume of the water can easily overload the inlet volume. This may back-flash the samples into the carrier line and other bad things. You can download the Agilent gas calculator and play with your injection volume and inlet temperature to find a set of conditions that MIGHt work better. You may be surprised at how low you'll have to go with your injection volume.

https://www.agilent.com/en/support/gas- ... alculators

The analysis of the list of volatile compounds presented clearly indicates that you are determining the amount of volatile components in alcoholic products and spirit drinks in accordance with Commission Regulation (EC) No 2870/2000 of 19 December 2000 laying down Community reference methods for the analysis of spirits drinks

You are using the 4-methyl-2-pentanol as an internal standard.

There is a simple and robust method for the direct determination of volatile compounds in ethanol-containing solutions. Practical usage of the method “Ethanol as Internal Standard” is presented, for example, here https://www.youtube.com/channel/UCXgL2c ... qtQ/videos
and here doi.org/10.1021/jf3044956 , doi.org/10.1051/bioconf/20191502030 .

Your questions, comments and suggestions are welcome.

Best regards,
Siarhei