Slashdot Mirror
Artificial Nose Works By Color
Alien54 writes: "As reported here in the Science Daily News, chemists Kenneth Suslick and Neal Rakow at the University of Illinois have developed an artificial nose that is simple, fast and inexpensive - and works by visualizing odors. Called "smell-seeing" by its inventors, the technique is based on color changes that occur in an array of vapor-sensitive dyes known as metalloporphyrins - doughnut-shaped molecules that bind metal atoms. Metalloporphyrins are closely related to hemoglobin (the red pigment in blood) and chlorophyll (the green pigment in plants) Smell-seeing arrays have many potential uses, such as in the food and beverage industry to detect the presence of flavorings, additives or spoilage; in the perfume industry to identify counterfeit products; at customs checkpoints to detect banned plant materials, fruits and vegetables; and in the chemical workplace to detect and monitor poisons or toxins. The full text is available as a PDF file (but is recommended for chemistry geeks only)."
Add that to the machines that analyze the "aura" of heated air that surrounds our bodies, and you can get a stinkometer the likes of which has been heretofore confined to the dark recesses of deodorant company imaginations. Till then, it looks like a cool approach to the problem of identifying smells electronically for all kinds of other purposes.
Actually, this is by no means a new idea. The East German Stasi had a program where smells were gathered through a variety of means and stored in sealed jars. The jars could be opened months, even years later and the scents (usually preserved on a piece of fabric) presented to bloodhounds and the like. Surprisingly enough, this actually worked pretty well.
References to this practice can be found in a number of places, including reporter's notes (search for "smell samples") archived at the Federation of American Scientists.
So it's fairly clear that people and governments are not only capable of doing this sort of thing, but, in fact, it has been done (and will be done again if it's deemed valuable, I have no doubt). However, it must be pointed out that the usefulness of electronic bomb sniffers and smell based weapons locators is huge, and, properly applied, would likely save many lives.
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Behold the Power of Cheese!
The possibilities for this invention in the field of law and order are huge, and we owe it to the hard-working police and security forces of the world to see it turned into an effective tool as quickly as possible.
After all, sniffer dogs, as effective as they can be. can only be used to do so much, and they have to be trained to alert their handlers to different smells. This device can just be programmed with a huge array of chemical "pictures" and used continuously instead.
In an age where FBI figures show an increase of about 12% each year in the amount of illegal high explosives seized, this kind of ultra-sensitive device is something we need.
Till then, it looks like a cool approach to the problem of identifying smells electronically for all kinds of other purposes.
I am not sure we might soon have some Stinkometer tomorrow as, if I understand that a device using this technology could detect some smell, and maybe recognize some that stink, there will still be issues about mixes, for example, if you take a flower perfume and some food smell, they could independantly smell good but their mix could smell awful (Roquefort cheese + flowers, for example).
Except in few cases when mixing odorous gas will induce molecular changes (that could reasonably make a sensor react properly), these smells will consist of sets of smell clouds which could independantly be analyzed but may probably not (yet) be classified as a unique smell type.
So, I accept the idea of an electronic nose though we may all agree that we need (1) enough sensors to detect all these subtilities (2) a brain in order to analyze the resulting smell by confronting all the sensor results simultaneously.
I don't even mention cultural facts that'll make (for example) alcohol, smell better for non-Muslims than for Muslims and thus will require different classification schemes.
A typical application of this study (IMHO) would be to detect gas (c3h8, c4h10) leaks in houses in order to avoid explosions. Cheers
PS: BTW, it is funny not to have a single occurrence of the word smell in the PDF file...
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Trolling using another account since 2005.
No longer will it only be those who partake of LSD that can smell colors (or colours, any spelling you like)
Finkployd
A system somewhat like this is half of what is needed to make the recording of odor/flavor precise enough for legal action--the other half is an understanding of what goes on in our brains in response to a given set of chemicals.
Note that if done properly, this will allow the digitization of odor. To play back an odor you'd spray a mixture of simple compounds that would have the same neurologic effect as the compounds being measured.
(Technical note: metalloporphyrins can potentially be used to inexpensively identify a large number of compounds simultaneously; mass spec requires a very expensive machine to do this.)
I'd like to really know how exactly that was a troll? Maybe it wasn't all that funny, but certainly not a troll.
Rami
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rJames.org - illustration
In a word, it's cheap.
Think of the potential of monitoring multiple sample points with a single optical detector/analyzer connected via optical fibers to hundreds (thousands?) of extremely cheap, easily-replaced sensors. If you tried to use mass-spec, you'd either have to have many spectrometers or a sampling system that brought the sample to a central analyzer. Photons are easier to move than molecules.
Even more useful, how about diapers?
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Do ya feel happy-go-lucky, punk?
Okay, I suck at chemistry, so feel free to step in and correct me, but isn't "smell by color" a pretty obvious method? The fact is that "smell" isn't really a sense, in the way that seeing and hearing are senses. Your body actually takes in some particles, and your brain looks them up in and determines what they are, then feeds you a sensation based on the response. (I know I've probably over-computer-metaphored this, but the point I'm trying to make is that all of this is abstract and methaphoric, since senses are just electro-chemical responses in your brain, and the computer doesn't have a chemical brain)
So the computer has to identify the chemical, then the process of recognizing it is the actual "smelling." The only two ways I can think of to identify a chemical are by physically contacting it with chemical receptors (this is the way noses do it, I believe, but this is far from practical with computers) or by looking at the molecules. Once you're looking at the molecules, the wavelength/frequency of light emitted (color) is the best way to recognize what molecules you're looking at.
So smell by color isn't nearly as odd as it sounds.
"producing an altered isotope of the metalloporphyrin"
BZZT! Unless you've discovered something new in nuclear chemistry, don't try that on your PhD orals. Perhaps you meant allotrope?
-- Alastair
20 posts and not one fart joke. I'm ready to weep tears of joy. I knew that /. was slowly improving due to Taco's inspired moderation technology and now we have proof.
/. fart-joke free and on-topic.
Thank you Taco and thank you slashdotters. Let's work together to make
Together we can make it happen.
--Shoeboy
"How does he smell?"
"metalloporphyrins..."
Nah...
scan, wipe, scan, compare
I don't know what's wrong with this, it's what I do with my real nose. Not to mention my ass. Is there something wrong with modeling artifical organs off of real ones?
--Shoeboy
Yes, my first thought was that the color nose should work particularly well on Fruit Loops.
Remember the shirts that changed color with body heat? People would walk around with big bright pink armpits - not quite the same as detecting stink, but it had the same effect. Besides, after you washed them a few times they got stuck. ;-)
The Divine Creatrix in a Mortal Shell that stays Crunchy in Milk
The House Between - Original Sci-Fi Series
After reading the pdf, and the news snippet, they seem to gloss over some relevent points. So you can get a color display of an oder. Last time I checked, there were over 430 compounds identified to cause an apple to smell like an apple. This was done with GC/MS. Why GC/MS? Because MS gives you a finger print of a molecule, by way of breaking it with a high energy source. Molecules break in a fashion that is unique to the individual molecule. By working backwards, knowing chemistry, and being very patient, you can rebuild the molecule. The only other techniques used to positivly ID molecules are really, NMR, and X-ray crystallography. But those techniques require a lot more sample. Next, the GC is one of the best seperating machines available, if run properly. But, still, 430 and counting for an apple. Sort of becomes apparent why those green candies taste more green than apple...
Now, the next question is does the array distingush between compounds with similar smells, for instance ammonia (NH3) and trimethyl amine ((CH3)3N) Both smell like ammonia, but there is an obvious difference in chemical formula and structure. Maybe that is nit picky, but think of this another way. Should the DEA arrest you for smuggling pot or for wearing hemp derived shirt. Other fun examples could be getting busted for amphetamines, or just owning some nutmeg (trust me, they have some very similar compounds) So, now it seems that accuracy is important.
But, think of the good points that this could have. The one that comes to mind is hazardous waste. Remember the movie "The Rock" and VX gas? The stuff really does exist, but you don't melt if exposed. We got it from the UK in the 50's for some nuc secrets. You muscles convulse, your back generally breaks. The problem with the stuff is it has a high vapor pressure (goes into gas phase easily) is sticky, and is toxic until the phosphonthiol bond it oxidized (broken) Also, there are a bunch of variations to the chemical structure, some more toxic that others, but who cares? If the array turns the wrong color, then break out the Haz-Mat suits and spray with bleach, pronto.
Finally, the PDF file doesn't really address the array nose. It is really a reveiw of that field. A neat way to check for NO (Nitric Oxide) Just in case you were wondering, it is a chemical messenger in your body. Short lived, used in processes like smooth muscle contraction. There is an enzyme or two that break it down. Funny thing it that Viagra is an inhibitor of one of those enzymes. But, back to the point, the metalloporphines (like heme and chlorophyll) can be use for cellular sized monitors of certain molecules (only one at a time)I believe that similar testing has been done before in the area of taste differences between operating systems.
From the FreeBSD FAQ:
credo quia absurdum
Well, those awful neon-colored kid's cereals DID claim that "purple" was a flavor...
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If they can make them cheap enough then I'm sure everyone will have them after a couple of years.
It just seems like something that sounds cool, but may not be all that practical in the real world.
...it suddenly turns red??
Every expression is true, for a given value of 'true'
The area where I see where this having the most popularity is in spying^H^H^H^H^H^Hlaw enforcement. We already have police dogs that sniff out criminals; electronic smell recognition seems to be a (un)natural extension of this. Can't you imagine the FBI or NSA with a huge database of peoples' "smells" and matching them with gloves left behind at a crime or sperm samples from a rape? Of course, you wouldn't have to register your smell with them -- after all, you don't really need that driver's license!
It's amazing how quickly technology is eradicating whatever notions of privacy that people still had. We already have our appearance, blood type, and actions recorded and disseminated all around the world; now we're going to have our smells tracked too? What's next, our skin texture?
Sorry I don't have a login, so I'll just post this with my name at the end.
This is just one example of a new field in biochemistry called "porphyrins". I've been working on them for my doctorate thesis for the last three years, but I never expected to see them mentioned on Slashdot.
The way metalloporphyrins (and the larger group of porphyrins) work is that when a particular molecule hits a pre-prepared surface coated with the dye, the metalloporphyrin alters its structure through movement in the electron shells to mimic the molecules form, producing an altered isotope of the metalloporphyrin that has different optical properties, reflecting only a select sequence of wavelengths. This is caused by the electron shells collecting energy from the photons as they arrive, and re-emitting them in accordance with Precontelli's principle of refraction.
Porphyrins have much in common with the family of chromopolymers, as well (at least in their macroscopic physical interactions. It's a very interesting field of research, and I hope that some future chemists might become involved.
-- Chris Ellendale
Ph.D candidate, University of California
For more information, see the following links:
Porphyrin Co., Ltd.
Summary of Porphyrins and Metalloporphyrins
Metalloporphyri ns
Photosensisizing effects of metalloporphyrins