Chemistry Forum

Hello everyone,

The company that I work for as a lab technician ( I'm the only one working in the lab as it s made of 2 containers used for production control with routine analysis as density, water content etc)is considering aquring an FT-IR ( using of a GC is a no way for them)to measure the hydrocarbons content in MEG and TEG which is used in a gas dehydration unit , where the gas is around 97% CH₄.
The main problem for me is that I am new in the spectroscopy area, the only reason they want to opt for an FT-IR is beacuse the previous analysis were done by a 3rd party laboratory. They use an in-house method which the only information they provided about the method is that they diluted the sample with water , extracted it with S₃₁₆ solvent, filtered through Florisil and then analysed with the FT-IR , and their results came as " Hydrocarbons ( n,iso,cyclo alkane) = x mg/l."
From my research I think this is kind of an adapted version of the water and wastewater TPH measurment.
Anyway my questions are:
- what kind of standards should I use to make the calibration line
- how do I make the calibration line
- can I use other kind of solvent like cyclohexane
-what kind of quvettes
-how to prepare my MEG and TEG samples to measure them
Basicly everything .
Thank you all for the attention and I m sorry if I made some grammatically mistakes.

- You will need standards with known concentrations of hydrocarbons in MEG and TEG. To create a calibration line, you will measure the infrared spectra of your standards at various concentrations. Plot the peak area or absorbance of the relevant hydrocarbon bands against the known concentrations. This will give you a calibration curve or line that you can use to determine the concentration of hydrocarbons in your samples.
- Cyclohexane can be a suitable solvent for extracting hydrocarbons from your MEG and TEG samples. However, it is important to consider the solubility of your target hydrocarbons in the solvent and any potential interference or interactions with other components.
- The choice of cuvettes will depend on the specific requirements of your FT-IR instrument. Quartz cuvettes are commonly used in FT-IR spectroscopy due to their broad spectral range.
- For MEG and TEG sample preparation, you may need to dilute your samples to fall within the linear range of your calibration curve. Follow the in-house method you mentioned, which involves dilution with water, extraction with a solvent, and filtration through Florisil.