| Author | Message | ||
     Tony Davies (td) Moderator Username: td Post Number: 228 Registered: 1-2001 |
Hi Benjamin, Welcome to the group! I'm sorry I have been a bit busy recently and didn't see your question. I'm wondering if you cann't make use of the phenol group in your agent. Would you like to make your spectrum available? I think you should have a rather broad peak around 2100 nm from the OH. However this broadening is due to hydrogen bonding (Actually this is a guess I'm not sure if I have worked with any phenols - do they hydrogen bond?). If you put this in a dilute solution of any hydrocarbon solvent the peak will become sharp and you might be able to use it for quantitative analysis. Good luck and best wishes, Tony | ||
| Mike Zapf (mzapf) New member Username: mzapf Post Number: 2 Registered: 1-2006 |
There was a "recent" paper in Applied Spectroscopy (3-6 months, 2010, 2009?) where the author had measured organic compounds in the presence of organic solvents. | ||
| Howard Mark (hlmark) Senior Member Username: hlmark Post Number: 314 Registered: 9-2001 |
Benjamin - you should check the Chemical Handbook under Freons (probably in the Industrial Chemicals section). There are several that are fully halogenated. While some of those are refrigerants and therefore have low boiling points, there are a couple (unfortunately I don't remember the exact designations) that have boiling points up around 80 - 110 degrees C. These have no -CH and are completely clear in the NIR, of course their suitability as a solvent for your analyte would need to be verified. Howard \o/ /_\ | ||
| David W. Hopkins (dhopkins) Senior Member Username: dhopkins Post Number: 139 Registered: 10-2002 |
Hi Benjamin, I'm assuming that your initial studies were with the agent as a liquid. I think that defining the extinction coefficient at several temperatures and reporting the pathlength of the cell would be a first step. Then you need to decide why you are doing this. If someone is interested in using the information as a guide to determining the concentration of a sample, you should use a solvent that they would likely use. Is there any such solvent in which it is routinely dissolved? Or, if you are interested in other solvents, I wonder whether cyclohexane would be a good choice? At least, I'd expect that you could readily subtract its spectrum. With your agent, I would expect solvent effects on the spectra, and certainly solute-solute interactions until the solute is sufficiently dilute, so you need to consider your purpose. Best wishes, Dave | ||
| Art Springsteen (artspring) Advanced Member Username: artspring Post Number: 25 Registered: 2-2003 |
Benjamin, If I remember correctly, and it has been a long time, we used tetrachloroethylene, which is much less toxic than carbon tetrachloride, as a solvent. It's still not great and 'friendly' but it's a lot better than carbon tet. I wouldn't think there would be many absorbances that coincide with the peaks in 2.6-diisopropylphenol. | ||
| Benjamin Weber (benjaminweber) New member Username: benjaminweber Post Number: 1 Registered: 4-2010 |
Hi everybody, I am working on a project regarding the detection of an organic agent (2,6-diisopropylphenol) using NIRS (1�m-2�m). My first guess was to measure the transmission using an air-filled cuvette as reference and a sample cuvette filled with the substance of interest. So I measured a nice spectrum and could assign the peaks/bands to its functional groups. To determine the molar extinction coefficent accurately, I'm planning to measure the transmission of the substance in solution, referencing to the transmission of the solvent itself. Here is the problem: Which solvent is preferable for this range? I know (and made the experience myself), that organic solvent are not useful, since their absorption interferes with the sample absorption. I read a lot about CCl4, yet I am looking for a more "friendly" solvent. Regards, Benjamin |