Fluorescent Tracer Particles Under Black Light

[Helepolis]

Hi all,

Pretty sure this isn’t the most suitable forum for this question but so far, my best bet for an answer.
So I’ll just try to explain what is the final goal, because I’m not entirely sure what I should be looking for.

We are trying to follow a stream of nebulized liquid through a transparent model representing the human upper airway tree.
The idea is to "flood" the model with “black light” and use a solution of the liquid with a fluorescent dye or tracer particles, of some sort, so that only the nebulized stream will be visible.

I was hoping to find something that is non-toxic and preferably bio-compatible, so if anyone can nudge me in the right direction, that would be great!
(I’m searching the web for an answer in parallel to this thread)

 

[EdStainless]

the dye is fluorescein, there is even an injectable version.
It fluoresces nicely,

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P.E. Metallurgy, Plymouth Tube

 

[Helepolis]

We have the stuff at the lab, but from the specs of the fluorescein it fluoresces best at 495nm light which is in the visible spectrum.
As the mist of the nebulized liquid is very fine, "flooding" the model with visible light will impair our ability to see the stream (my assumption), this is why I'm looking for something that might work under the "Blacklight" spectrum.

 

[EdStainless]

Call one of the suppliers of inspection products and ask about florescent penetrant products.
I have used flourescein for inspection inside of food processing tanks. I used standard black lights and got very good visibility.

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P.E. Metallurgy, Plymouth Tube

 

[jari001]

UV light and aqueous riboflavin solution are a combo I've used.

 

[Helepolis]

Call one of the suppliers of inspection products and ask about florescent penetrant products.
I have used flourescein for inspection inside of food processing tanks. I used standard black lights and got very good visibility.

UV light and aqueous riboflavin solution are a combo I've used.

Do you remember the wave length of the black light?

I've checked on wikipedia for the wave length for optimal emission, but in case i wouldn't find the correct lamp...

 

[EdStainless]

I used a generic hand held FPI lamp.
We used flourescien because it was food grade (actually injectable) and if we left traces in the tank there would't be contamination issues (unless you are worried that your beer glows).

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P.E. Metallurgy, Plymouth Tube

 

[moltenmetal]

Fluorescein absorbs strongly in the near ultraviolet, so you can use a visible filtered UV lamp (i.e. a "blacklight"). The only light you will see is the green light emitted by fluoresecense from the fluorescein-doped particles.

If there is a mist, however, you may still not be able to see anything, not due to wavelengths but due to scattering.

 

[jari001]

I tend to agree with moltenmetal, you likely won't be able to see the nebulized stream because the bubbles will be too small.

Just in case -
The lamp I used was something like the following:

https://www.uv-light.co.uk/blacklight/hand-held/35w-hand-lamp/

I don't have access to the instrument anymore to dig up it's spec sheet but what I remember is that the lamps match with some of the local maxima of the absorption spectra in the 400nm range.

 

[Helepolis]

Thank you guys for the help!

I will go for the lamp with the specified wavelength, just to be sure that there will be the maximum amount of excitation from the nebulized stream.

About the ability to se the glow from the nebulized stream, I hope that I will be able to see it with the naked eye, as we used a 2.26W, 532nm green laser to outline a bolus of the nebulized solution w/o the fluorescein, we were able to see it with the naked eye (see attached photo).
But in case you are right, and the glow will be barely visible, we plan to use a specialized camera to filter the photo/video.

 

[moltenmetal]

If the filtered UV irradiation is intense enough, the fluoresence will be quite strong- fluorescein's quantum yield of fluoresence is quite high.

 

[Helepolis]

I used a generic hand held FPI lamp.
We used flourescien because it was food grade (actually injectable) and if we left traces in the tank there would't be contamination issues (unless you are worried that your beer glows).

Do you remember by any chance the percentage of the flourescine in your solution.