The key problem with coupling IR technique is very strong absorption by solvents especially water. FTIR is not sensitive either, ATR makes it worse. Still people have coupled LC-FTIR.

Article Liquid Chromatography–Fourier-transform Infrared Spectrometry

Dear Sherif,

The FTIR detector is suitable for the HPLC analysis of metabolites with poor UV absorptions. We used this detector for the preparative HPLC separation of steroidal saponins and the detection was very nice (https://www.researchgate.net/publication/307549944_Trifasciatosides_A-J_Steroidal_Saponins_from_Sansevieria_trifasciata ).

Best regards,

It depends on your molecules. Better if you can check their FTIT-ATR spectra prior in the pure form and confirm yourself.

Otherwise, this is not as suitable as UV-Vis or MS.

- Thanks M. Farooq Wahab , Rémy Bertrand Teponno and interesting application Udaya Jayasundara for your comments.

- dr M. Farooq Wahab , This paper was from a very long time and I think the technique has evolved a lot since that date. In our previous publication:

Article Attenuated Total Reflectance Fourier Transformation Infrared...

we used ATR-FTIR as a detector in a continuous flow circulation and it was applicable for determination of certain metabolite in a deficit matrix. this encourage us to suggest connecting ATR-FTIR to HPLC. I want to know if anyone has a previous experience with this ?

- this main issue is that FTIR can record one spectrum each minute "nearly". I do not know can I decrease number of scans to decrease this time ?! also, what pressure can be tolerated by the prism and so on ..... I think the solvents absorption can be cancelled as a blank.

what do you think ?

Sherif Mohamed Eid , The sampling rate is another major limiting factor. If you are talking about a complete scan is one minute, this rate is nowhere near the sampling rate employed in UV-Vis or other HPLC detectors. If you are looking for one specific band, then it is another story. The typical rate in HPLCs is about 20 Hz (20 data points per second). Modern UHPLCs operate around 160 to 250 Hz. Check the literature to see others have done in LC-FTIR.

The outlet pressure of a liquid chromatography detector is same as atmospheric pressure.

Hi Sherif,

have a look at this article by Peter Kilz and Harald Pasch:

https://www.pss-polymer.com/uploads/tx_pss/pdf/publication/hyphenated%20techniques%20in%20EAC.pdf

Although it deals with the analysis of polymers, it can also be transferred to smaller molecules.

Regards

Markus

You may use Photo Diode Array ( PDA ) detector .