| Author | Message | ||
     Howard Mark (hlmark) Senior Member Username: hlmark Post Number: 176 Registered: 9-2001 |
Kathryn - have you checked the new (3rd) edition of the NIR Handbook? There are several chapters where the title indicates identification: chapters 29-32, for example, and chapters 38 & 39, at least. Several of the others seem likely to include qualitative methods as well as quantitative ones. Howard \o/ /_\ | ||
| kathryn lee (kathrynlee) Junior Member Username: kathrynlee Post Number: 6 Registered: 2-2004 |
I would very much appreciate your help. I am looking for patents or technical papers that discuss the application of IR, either NIR or mid-IR, to predict product performance using a library. I think there are a lot of publications about product quality, which of course predicts product performance, but if possible, I would like references that discuss product performance directly. All references will be appreciated. Thanks | ||
| Michael C Mound (mike) Senior Member Username: mike Post Number: 42 Registered: 7-2007 |
David, An interesting idea. However, the comment made to me had to do with attenuation rather than a kind of specular reflection, though you might be correct. Thanks for the input. Still, I don't understand how these folks from the university (Reckettbenkiser in the UK) were so sure that there would be no attenuation, while others complain that NIRS is blind when both Ti and Fe are present. For me, the penetration through think coatings is important inasmuch as some of the materials in my applications have such oxides in dust particles. Mike | ||
| David Russell (russell) Senior Member Username: russell Post Number: 37 Registered: 2-2001 |
It would seem to me to the extent that the Fe and Ti in the coating cause it to be reflective, it would effect the penetration depth for the NIR measurement and reduce the available measurement signal. | ||
| Michael C Mound (mike) Senior Member Username: mike Post Number: 41 Registered: 7-2007 |
Hi, Howard, The issue began with a discussion relative to checking PCA and excipients with placebos in clear gel capsules, so I cannot really think that there was a particle size issue. However, I could be off base on this. My concern was if such attenuations were a general matter or simply a one.off issue depending on the encapsulation system. I'll have to research this further, but your response helps. Thanks, Mike | ||
| Howard Mark (hlmark) Senior Member Username: hlmark Post Number: 175 Registered: 9-2001 |
Mike - seems to me it would depend very much on the form that the Fe and Ti are in. Are they present as metal particles, or as ions, or as an appendage to a larger organic molecule (e.g., hemoglobin)? If metal particles, what is the particle size? If as ions, what anions are they associated with? Are those salts soluble or insoluble? If insoluble, then again the question of particle size arises. The list of possibilities goes on, but the point is that the answers to those questions will all make a difference in the expected behavior, and that the mere presence of the isolated atom tells very little about how it will affect the NIR properties. \o/ /_\ | ||
| Michael C Mound (mike) Senior Member Username: mike Post Number: 40 Registered: 7-2007 |
Folks: I have seen in the literature that gelcap coatings which contain Fe attenuate NIR responses and those which contain both Fe and Ti "blind" NIRS. I mentioned this in a recent meeting on NIR Chemical Imaging, and two researchers from a University in the UK claimed that they experienced no attenuation whatsoever. Anybody have a similar or different slant on this? Thanks, Mike |