| Author | Message | ||
     Dennis Pliutau (dpliutau) New member Username: dpliutau Post Number: 2 Registered: 5-2006 |
Thank you once again. | ||
| Michel Coene (michel) New member Username: michel Post Number: 30 Registered: 2-2002 |
Fluorescence has the great advantage that only secondary radiation hits the detector, i.e. your detector does not "see" your source. It is easier to tell the difference between nothing and almost nothing then between a lot and (a lot minus almost nothing). Are you considering NIR because it is cheaper? In that case I would say no, because what you save in equipment you will pay in calibration work (if it is at all possible). If LIF can't do the job, your only chance of success is if the elements you want to detect have strong bands FAR away from the OH bands, so you can use a large pathlength. On top of that, you will probably need accurate thermostatisation, degassing and the removing of all particles which could cause scattering. Any book on NIR will start by telling you it is not a trace element technique. Sometimes you can go quite low if you have an easy and stable matrix, but teaching an old dog new tricks should be avoided whenever possible.. | ||
| Dennis Pliutau (dpliutau) New member Username: dpliutau Post Number: 1 Registered: 5-2006 |
I was wondering if anyone could tell his opinion on whether it would be possible to apply NIR absorption spectroscopy to the determination of organic impurities in water effectively as compared to Laser Induced Fluorescence. I am particularly interested in whether the sensitivity of NIR would be enough to detect traces of organics in water. As far as I know NIR is far not that sensitive as LIF is. What is NIR sensitivity as compared to Laser Induced Fluorescence in general? Thank you. |