# Using IR to detect / quantify a molecule at low concentrations

I want to detect / quantify a specific terpenoid molecule from a microbiological growth medium. The molecule will however be present at very low levels approx. 10-100 mg/L.

Is it viable to use the IR spectrum to detect this molecule at such low levels? If not quantitatively at least in a qualitative sense? The idea is to have some sort of method that is amenable to reasonably high throughput screening.

A GC / GCMS which is the typical assay method is too time consuming for screening a lot of samples.

The IR spectrum is shown below. Can I just monitor a specific wavelength with max absorbance, (say) 3000 cm-1? That way I won't have to scan the whole wavelength range.

Any other ideas?

I suspect that the peak at 3000 $\mathrm{cm}^{-1}$ is an alkyl CH stretch. You're going to see similar absorption peaks in lipids and proteins, so I don't think that particular peak is going to be too promising for you.