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NIRman
Posted on Tuesday, January 29, 2002 - 1:19 pm:   

The American Chemical Society has seen fit to list me on the Speaker's Circuit with a talk entitled "Catch 'em with Near-IR" and dealing with the detection of counterfeit currency, turquoise gems, and ivory. I would dearly love to expand the subject matter but haven't found anything worth including. Does anyone reading this query know of papers dealing with other fake materials that have been identified by NIR?
Though retired from Los Alamos National Laboratory, I remain as a guest scientist with access to a FOSS-NIRSystems Model 6500 with both reflectance and transmittance probes. Don Burns, 2 La Flora Court, Los Alamos, NM 87544.
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Art Springsteen
Posted on Tuesday, January 29, 2002 - 2:44 pm:   

There is a lot of anecdotal work done on filling gemstones with oils, etc. But the gem community is very closed-mouth about it. I've also done some work on ivory, determining between the so-called 'polymer ivory' and the real stuff (that's a piece of cake in the NIR). All the currency work I've done has been in the Vis, but the NIR (and fluorescence) are probably better analytical techniques. I've done some work using both a P-E Lambda-19 and with a PE 2000 FT-IR on this stuff, years ago. Major problem is sample presentation.

I might have some papers on filling of precious stones (emeralds, rubies, and diamonds) with oils- they put an oil with similar refractive index under pressure and the cracks disappear.
I too have a Foss-NIRS 6500, along with a couple of P-E 9/19's.

Good luck!
Art Springsteen
Avian Technologies LLC
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MRCTNIR
Posted on Tuesday, January 29, 2002 - 4:03 pm:   

Hi Don!
Hope to see you at IDRC this year. Anyway, one hot topic that I am dealing with is counterfit drugs. You might try to talk to Pat Faustino or Everett Jefferson at the FDA / CDER, where they are very active in trying to discern the innovator products from the stuff from Mexico for instance! Very nice work so far. (Ask Emil). Until the summer...

Gary Ritchie
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Christel Solberg
Posted on Wednesday, January 30, 2002 - 1:53 am:   

I think new instruments like Perten DA have some rather good benefits for sample presentation, because one illuminate the sample with the whole spectrum and diffract the reflected light. One doesn't have to woory about straylight in the way one has to do with instruments like NIRs. The Perten DA instrument is rather good in the VIS area. With this instrument I have succeeded to analyse the carotenoid concentation (mg/kg) in salmon fillet. I have tryed to do it with other instruments, but they hav not been good enough in the lower VIS region.
Looking forward to hear more about preventing counterfeit of gemstones.
Christel Solberg
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Art Springsteen
Posted on Wednesday, January 30, 2002 - 5:26 am:   

Christel Solberg wrote :

Don't get me wrong- the Perten DA is a very nice instrument but I wouldn't think it's suited to doing gemstones. The illumination is over a large area and gemstones tend to be quite small. Basically, you want the illumination beam focussed onto the stone and a sphere to do the collection. I think the Perten instrument would have a very hard time getting good enough S/N to do small stones. Nice for salmon, not so good for diamonds :)

Art Springsteen
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ronrubinovitz
Posted on Wednesday, January 30, 2002 - 5:59 am:   

Some examples of gemstone analysis for synthetic or "fissure-filled" samples of gemstones can be found in the articles below (These can also be downloaded from www.iscpubs.com as PDF files). As far as the illumination size discussion that I have seen I would agree that it is an important consideration and point out that some samples can be quite small (<5 mm) while others, particularly turquoise can be, by comparison, quite large (10-20 mm). I hope this is of some help !


�Rapid Spectroscopic Discrimination Between Natural and Synthetic Emeralds, Rubies, and Alexandrite� Daniel W. Armstrong, Xiande Wang, C.R. Beesley, and Ronald Rubinovitz, American Laboratory Vol. 32 (13) 26 (2000)

�Analysis of Fissure-Filled Turquoise, Emeralds, and Rubies by Near-Infrared Spectroscopy� Daniel W. Armstrong, Xiande Wang, C.R. Beesley, and Ronald Rubinovitz, American Laboratory Vol. 31 (20) 41 (1999)


Ronald Rubinovitz

Buchi Analytical Inc.
19 Lukens Drive, Suite 400
New Castle, Delaware 19720
e-mail [email protected]
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ronrubinovitz
Posted on Wednesday, January 30, 2002 - 6:05 am:   

For some reason the articles I referenced ((American Lab Vol 32 (13 26 (2000) and American Lab Vol. 31 (20) 41 (1999))did not appear so I will try again...

Rapid Spectroscopic Discrimination Between Natural and Synthetic Emeralds, Rubies, and Alexandrite Daniel W. Armstrong, Xiande Wang, C.R. Beesley, and Ronald Rubinovitz, American Laboratory Vol. 32 (13) 26 (2000)

Analysis of Fissure-Filled Turquoise, Emeralds, and Rubies by Near-Infrared Spectroscopy Daniel W. Armstrong, Xiande Wang, C.R. Beesley, and Ronald Rubinovitz, American Laboratory Vol. 31 (20) 41 (1999)

Ronald Rubinovitz

Buchi Analytical Inc.
[email protected]}
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Dave Ryan (Ryan)
Posted on Wednesday, January 30, 2002 - 6:12 am:   

Hi Don

I remember a paper presented at I believe the 38th EAS that discussed gemstone quality using NIR. I don't remember the author, however I have a contact at the American Gemological Laboratories. His name is C.R. Beesley and the phone is 212-704-0727. Hope he is willing to help. Hope to see you at Chambersburg. Take care.

Dave Ryan
Central Soya,Inc.
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TD
Posted on Wednesday, January 30, 2002 - 10:57 am:   

Hi Don,

On the fake pharmaceutical front I heard a very nice lecture by Steve Hammond (Pfizer UK) but I do not know if it is public domain. If you want some lateral thinking there has been a lot of work done in the food area and some in fine art. (that's not Springsteen!).
I'm also looking forward to being in Chambersburg in August - and the PYOT.

Best wishes,

Tony Davies
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NIRman
Posted on Saturday, February 16, 2002 - 11:25 am:   

Acorns and pigs!

An unusual and interesting use of NIR for the detection of fraud was brought to my attention by Bruce Campbell. He read of it about 5 years ago, but he doesn't recall where he saw it. Can anyone shed light on this?

In Spain, pigs are sold in 3 classes, with the most expensive class being those that had eaten the most acorns, the next class had eaten less, and the 3rd class none. It seems that the acorns made the pork taste better, and NIR could classify the pigs before they were turned into a meal.

Don Burns
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Ian Michael (Ianmichael)
Posted on Saturday, February 16, 2002 - 1:34 pm:   

This may be it:

http://www.impublications.com/discus/abs/J06_A307.html

No mention of acorns in the abstract, but they are in the paper.
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Td
Posted on Saturday, February 16, 2002 - 2:03 pm:   

The reference to the original work is : JNIRS 2,177-184 (1994).

Note also that the reference Ian gave is in the "A" pages of volume 6 (NIR-97).

Tony

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