IDENTIFYING UV DYE IN A LIQUID.

Discussion in 'The Projects Forum' started by geofffinlay, Aug 28, 2015.

  1. geofffinlay

    Thread Starter New Member

    Apr 5, 2013
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    I'm starting a project where I need to identify a specific liquid. I'd like to add clear UV dye to the liquid and use some kind of photo diode to authenticate the liquid as the correct product. Does anyone have any suggestions where to start?

    Geoff
     
  2. mcgyvr

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    Oct 15, 2009
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    How would that help to identify the liquid? The "correct" product is simply the one you added the die to.. So just stick a label on it instead and verify presence of the label..

    It "might" help to explain your project a bit more so we can either offer suggestions on your idea or maybe offer better ones.

    Simple UV detection here..
    http://www.keyence.com/products/sensor/photoelectric/cz-v20/index.jsp
     
  3. jpanhalt

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    Jan 18, 2008
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    There are a huge number of possibilities. First, what is the liquid? Some choices will not be very soluble in water. Second, is there any chance the liquid will be ingested?

    Many fluorescent dyes are also colored in the visible too. Do you want something that is completely colorless, like 2-naphthol, or can it be slightly yellow, like fluorescein? What is the longest excitation wavelength that you can use?

    John
     
  4. #12

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    Nov 30, 2010
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    I think this is called, "ink". Some places use it to stamp customers when they pay to get in the bar.
    If you work for the ATF, you might need a lot to mark hundred dollar bills for your next drug purchase.
    Still, this ink does not contain transistors, but there are a couple of chemists here. ;)
     
  5. joeyd999

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    Just my 2 cents: If you add a dye to an "authentic" liquid, it ceases being authentic.
     
  6. jpanhalt

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    Besides, there are much better ways to tell whether an expensive whiskey is the real stuff or not.

    John
     
  7. GopherT

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    Back up.

    Tell us again what you want to do - from the beginning.

    Example 1) I have several vials of liquid. I want to call one the "authentic one" and it will need to light up when exposed to a black light (so you want to add a UV dye to it to make it light up)

    Example 2) I have a known liquid (Authentic sample). I have a table full of unknown samples. I want to add my UV dye to a small sample of my authentic sample and measure the absorption spectrum and look for any unique characteristics. Then add UV dye to all of the other unknown samples and measure the UV spectrum of those to find out which unknown samples are the same as my Authentic sample.

    Example 1 is easy. Example 2 is difficult unless all of the non-authentic samples have much different polarities or charge-transfer (donor/acceptor) characteristics than the authentic sample.

    If you have an Example 3 option, let me know.
     
  8. geofffinlay

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    Apr 5, 2013
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    This is to all your replies, thank you. I'm building a product that is automotive repair related. It uses a solvent for cleaning carbon. The solvent is held in an aluminum canister and there are sensors inside the canister. During development we added something to the solvent to prevent the sensors from being damaged. We will be supplying the solvent to the end user, which they will pay for. History tells us that auto techs, being what they are will try to find cheaper solvents than ours. The end user will not know that we can identify our solvent, until their equipment won't start up because the PLC didn't get a positive ID from the solvent. Of course our own solvent will be prominently labelled with a warning to use only our solvent.

    I hope that's a little clearer - Geoff
     
  9. jpanhalt

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    You have to tell us about the UV properties, most important the UV transparency of the solvent. A UV tag won't work if the solvent is not effectively transparent at its excitation and emission wavelengths. 2-Naphthol is colorless and is soluble in many organic solvents. It may even be soluble enough in water to work.

    All that said, I don't think a simple UV tag will be a very robust deterrent to those who want to pirate your solution. You may need something more sophisticated like the counters included in toner cartridges or an encrypted code method with a chip in your solvent container and a code reader in the device.

    John
     
  10. #12

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    Ah, captive parts designed to make the product un-repairable without paying your special price. A noble goal indeed!
     
  11. joeyd999

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    And, likely, better.
     
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  12. GopherT

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    John,

    I just heard of an automotive decarbonizing system that uses a proprietary fluid to decarbonize and some type of UV system to insure the solution was provided by the right manufacturer. I cannot wait for it to come out because all I will have to do is shoot a sample through our GC/MS and get the UV-absorbing molecule that they use. I was wondering if you want to go in with me to run a business to make knock-off solution.

    I have $1k to spend on finding their proprietary UV absorber and then another $100k to find all the people who have purchased one of these units that will need the solution. Then, we can find a supplier of the UV molecule, the solvent and a company willing to blend, package and label the material. Then we will need to find someone to crate MSDSs, we will have to join ChemTrec in case anything is spilled in transit or if anyone claims an injury due to contact - must have that 24hour reporting hotline. Then, depending on the volumes we produce, we will have to submit our plan and get approval from state/local regulator bodies, then find a warehouse willing to store this material (will have to supply MSDSs and jump though lots of hoops if it is hazardous (flammable/corrosive/toxic/...) - God forbid that it is a teratogen or cancer suspect agent (better pay for testing related to that as well). Many powerful UV absorbers have issues according to their MSDSs.

    On the other hand, we can make a knock-off of the device (hardware) and let someone else take the risks and hold the liabilities of dealing in chemicals.
     
  13. jpanhalt

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    In considering the additional information and assuming the liquid you provide will become dirty with carbonized hydrocarbon stuff, I don't think a simple UV fluorescent dye will work. The solution itself may well become fluorescent from the polyaromatic hydrocarbons it has removed in the "carbon", or those materials will quench any fluorescence your additive may produce.

    One can conceive of simple chemical or photochemical detectors or detectors of reaction products from a substance added to your solution that might work, but clearly, if we are to go in that direction, we need more information about your magic solution and the stuff it dissolves.

    John
     
  14. jpanhalt

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    My point exactly. There is nothing simple that can be added that cannot be detected and identified by a graduate student at a major university over a weekend. That is why I suggested some code device like are included with many reagents for clinical testing.

    Nevertheless, if the TS wants to go down his original path, a UV tag will not work, so I suggested alternatives.
    John.
     
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  15. GopherT

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    John,

    Normally, these solvents are flushed into the throttle body as an aerosol while the engine is running fairly fast. The solvent is flooded into the air intake at such concentration that the engine almost dies and the cold shock of the solvent into the head causes the carbon to detach from the piston / cylinder head.

    No recycling needed. No real technology needed - MEK or n-Decanol (safer) works fine.
     
  16. jpanhalt

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    I thought (mistakenly?) that the intended use was in rebuilding engines, such as decarburizing pistons and such after disassembly. I have not played much with IC engines since 1995.

    John
     
  17. GopherT

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    I just recently bought a POS motorcycle since my college-age kid took my car for the summer. Finally have the car back but that $800 bike cost me a fortune - interesting experience though, I learned a lot about decarbonizing engines and such.
     
  18. LDC3

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    This sound vaguely familiar. Oh yeah, HP printer cartridges. ;)
     
  19. geofffinlay

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    Apr 5, 2013
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    That's all very funny stuff and I do appreciate your collective sense of humour. Thanks to the serious posts, but I have it figured out.

    Geoff
     
  20. #12

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    Nov 30, 2010
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    Always happy to see another product held hostage by modern improvements. I just bought a 2005 Ford Explorer, cheap! Now I know why. Spare ignition keys cost over $100 each...or I could hire a hacker to type a, "1" into a place in the software for $400...or I could just hope the, "safety lock-out" feature never breaks...or I can just plan on junking it when the software goes bad. We need more microprocessors in everything!
     
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