Fluorescein dye

MarkS

Moderator
The liquid solution I've used before was deep red in colour, a bit like iodine - but turned green instantly on contact with the stream water. Fluorescein was handwritten on the bottle...but maybe it was Rhodamine...?
Sounds like fluorescein - it can look red in a very concentrated solution.
 
The panic in the morning, before you remember you ate Beetroot last night! o_O
Suppose a word of caution, about 3 years ago my pee went red and I explained to myself with having eaten red jelly or beetroot in something. It wasn't it turned out to be an enlarged prostate, uncomfortable but dealt with quite happily. Sometimes it's still too normal to think it'll be better tomorrow, not always the case.

Jim (alias an old git, sometimes)
 

langcliffe

Well-known member
Suppose a word of caution, about 3 years ago my pee went red and I explained to myself with having eaten red jelly or beetroot in something. It wasn't it turned out to be an enlarged prostate, uncomfortable but dealt with quite happily. Sometimes it's still too normal to think it'll be better tomorrow, not always the case.

Mine was a kidney stone. If anyone tell you that passing a kidney stone is a piece of piss, don't believe them.
 

pwhole

Well-known member
Yeah, I spent four days in hospital twice when I got them - thought I was going to die the first time.

And yes, fluorescein looks red in the bottle:

index.php
 

Fred

Member
IIRC Absinthe was "inadvertently used" in the Doubs and a connection proved (*). I think I remember reading about the after effects of a fire at the Pernod distillery (on the banks of the Doubs?). It resulted in thousands of litres being dumped in the river (deliberately to try and remove it as a fuel from the fire). This turned the river white and similarly coloured water was later seen at one of the other resurgences.

(*) Might be more expensive and ecologically damaging than flourescein.
 

Stuart France

Active member
Nope. What you had really was fluorescein. The powder itself is a rusty red colour, and so is a conc solution of it, definitely nothing green. The fluorescent green hue only develops at the very diluted stage.
 

darklord

Member
Thanks for confirmation (y)

If I make up a solution, should it be released into the stream slowly?....so as to 'string out' the plume? Or do you just tip it in and let the stream do the work?
I'm only thinking that perhaps a short plume has a greater chance of being missed by observers. The distance I'm likely testing may be under 100m, but in a relatively fast flowing small stream. A short plume might just shoot through unnoticed..?
 

pwhole

Well-known member
Thanks for confirmation (y)

If I make up a solution, should it be released into the stream slowly?....so as to 'string out' the plume? Or do you just tip it in and let the stream do the work?
I'm only thinking that perhaps a short plume has a greater chance of being missed by observers. The distance I'm likely testing may be under 100m, but in a relatively fast flowing small stream. A short plume might just shoot through unnoticed..?

If you have detectors in place it doesn't matter if it's a quick plume, it's just knowing when it passed through is the tricky part, without digital sampling equipment.
 

mrodoc

Well-known member
I have heard that if you drink some then your pee turns fluorescent green as it is excreted un-metabolised. Could cause a stir in the gents or feminine equivalent. So it's best if you can arrange things to avoid any phone calls from the public about little green men from alien spacecraft etc etc.

I think just 100g of fluorescein powder would do the job if you wanted to reproduce the Canal & River Trust Effect.
I have been injected with fluorescein a couple of times relating to my eyes. It basically saturates you then is excreted through the kidneys. You glow under UV light, light up the gents and you might want to warn your partner before you get frisky after one of these injections.
 
  • Like
Reactions: mat

braveduck

Active member
Sounds like fluorescein - it can look red in a very concentrated solution.
I first job was at a place where it was made . I was able to get the recipe and made some !A mixture of Phallic Anhydride and Resorcinol .Heated dry to a red sticky blob . Dissolve ,precipitate ,filter and dry . It can be used as a wool dye ,but the light fastness is terrible ,it dyes wool Yellow .
 

darklord

Member
If you have detectors in place it doesn't matter if it's a quick plume, it's just knowing when it passed through is the tricky part, without digital sampling equipment.
The 'detectors' will be people looking for it! ;)

Yeah, I know I could put swabs in (have always done that with OBA), but then it's another trip to collect them etc. etc. In this scenario, we just want a quick visual on the evening: either they see it or they don't.
 

Fulk

Well-known member
If the sink to (putative) resurgence distance is not too far, then it should be easy enough to get somebody stationed at the supposed resurgence in plenty of time to see the results of the test. But – be careful of how much fluorescein you use.

I once did a flood-pulse / dye test of Short Gill Cave in Barbondale, and sure enough the flood pulse came through to the resurgence very quickly (pretty well instantaneously in human terms) while the dye took an hour or two to come through, thus indicating that it spent some time traversing a sump . . . but when it did, it coloured Barbon Beck all the way down to Barbon village, at which point we decided to call it a day and absquatulated.

Similarly I once tested Robin's Dub Cave to its resurgence on the other side of Deepdale Beck – it thus having gone under the beck. Deepdale Beck joins the Dee in Dentdale, and again the Dee was green all the way down to the village.

It seems that somehow the dye spreads out, rather than travelling as a sort of bolus down the river – an effect accentuated by diffusing slowly through a phreatic zone.
 

harrylong

Member
Over the years I have carried out many fluorescein tests and learnt that it is probably better to try and extend the plume by injecting the dye in several small amounts spread out over a period of time. This gives longer for potential observation and may well reduce the strength of colouration at any given point.

My best "clanger" was dumping quite a large quantity into a flow directed down Strans Gill Pot entrance. This was seen at the rising down on the bank of the River Wharfe and just starting to flow down the river after 5 hours. The next day when I visited Kettlewell I found the river there was quite strongly coloured: a condition that lasted for at least another day!
 

darklord

Member
If the sink to (putative) resurgence distance is not too far, then it should be easy enough to get somebody stationed at the supposed resurgence in plenty of time to see the results of the test. But – be careful of how much fluorescein you use.

I once did a flood-pulse / dye test of Short Gill Cave in Barbondale, and sure enough the flood pulse came through to the resurgence very quickly (pretty well instantaneously in human terms) while the dye took an hour or two to come through, thus indicating that it spent some time traversing a sump . . . but when it did, it coloured Barbon Beck all the way down to Barbon village, at which point we decided to call it a day and absquatulated.

Similarly I once tested Robin's Dub Cave to its resurgence on the other side of Deepdale Beck – it thus having gone under the beck. Deepdale Beck joins the Dee in Dentdale, and again the Dee was green all the way down to the village.

It seems that somehow the dye spreads out, rather than travelling as a sort of bolus down the river – an effect accentuated by diffusing slowly through a phreatic zone.
I wonder what quantities you were injecting to turn both small (Barbon Beck) and medium (Dee) size rivers green!

Last night I introduced a 100ml concentration of fluorescein (about 4-5g of powder) at the downstream limit of a cave to test a putative distance of under 100m to another nearby cave. Observers saw no green water and a swab which they placed while they were working for 2hrs proved negative.

However, on an earlier test a couple of weeks ago the dye had been introduced to the sinking surface stream - and that had proved positive to the other cave within 20 minutes (an unmissable visual, as the observers reported.)

It would seem that we have a splitting stream within the cave!
 

Fulk

Well-known member
I wonder what quantities you were injecting to turn both small (Barbon Beck) and medium (Dee) size rivers green!

Sorry, I can't remember, but it wasn't a lot in both cases (though that rather does beg the question, 'What is a lot?'!).
 

Stuart France

Active member
If your potential connection is only a distance of 100 metres or so, then I would put no more than half a level teaspoon of the powder dissolved in a litre of water and pour it all in at one go. It might take half an hour to get to the destination. I'm not sure about the maths but remember that your litre is continuously mixed and re-mixed with the water already occupying the stream and it gets progressively diluted and churned up as it goes along. I don't think pouring it in gradually will bring any benefits - the stream does that mixing and dilution for you. Don't expect it to come through in just a few minutes. Suppose a ping pong ball would move downstream at 5cm/sec floating on the surface, then it does a metre in 20 sec, so 100m in 2000 sec, say 30 minutes, but the dye isn't a ping pong ball because it gets mixed with a lot of slow or static water sat in all kinds of nooks and crannies on its travels so would be slower. You don't need any instruments, you'll see the dye if it's there.
 

darklord

Member
If your potential connection is only a distance of 100 metres or so, then I would put no more than half a level teaspoon of the powder dissolved in a litre of water and pour it all in at one go. It might take half an hour to get to the destination. I'm not sure about the maths but remember that your litre is continuously mixed and re-mixed with the water already occupying the stream and it gets progressively diluted and churned up as it goes along. I don't think pouring it in gradually will bring any benefits - the stream does that mixing and dilution for you. Don't expect it to come through in just a few minutes. Suppose a ping pong ball would move downstream at 5cm/sec floating on the surface, then it does a metre in 20 sec, so 100m in 2000 sec, say 30 minutes, but the dye isn't a ping pong ball because it gets mixed with a lot of slow or static water sat in all kinds of nooks and crannies on its travels so would be slower. You don't need any instruments, you'll see the dye if it's there.
Thanks, Stuart, I get you on all that. We have a reasonably fast moving stream I'd say in the order of 20-30cm/sec - at least as far as the eye can see (and in wet weather it can be heard rushing or falling further ahead), so I'd say a fairly quick flow-through time is to be expected.

To be honest, I didn't get the feeling the Monument (Toolstation) fluorescein was particularly concentrated. I wonder if it's the true C20H10Na2O5...:unsure:

Just a quick question on detectors: in the abnsence of human observers, what is the common material for detector swabs? I seem to remember in the past having heard of charcoal detectors for fluorescein? I've long been using pure, untreated cotton wool swabs and UV light on OBA tests. Does that work for fluorescein, too?
 

Pitlamp

Well-known member
I think you need "activated" charcoal in fine mesh bags as detectors. There is also a necessary lab process using various reagents to elute the fluoresceion from the charcoal granules.

I don't think cotton wool works with fluorescein.

I've generally found OBA and cotton wool to be the most convenient method. Les chance of accidentally upsetting somebody at the resurgence end too.
 

Stuart France

Active member
Put the charcoal granules under test into dilute NaOH, a dash of isopropyl alcohol, then heat up and swill around. The green dye is released back into the liquid. It is then more easily noticed under UV light. Obviously you are going to wear some eye protection, aren't you.

The OB method is an easier process because the least you need to do is recover the strip of cotton wool dressing from the stream and test alongside a 'control strip' that has not been exposed to OB using a UV lamp. Boots sells 5x5cm sterile packs of these dressings, easily cut up into smaller test strips. My photos show such a strip attached to a DIY electronic detector where the data logger turns on the UV LED for couple of seconds when it wants a reading, say every 15 minutes, and measures the reflected visible blue light passing through a blue perspex filter glued on top of a light dependent resistor (LDR) configured to produce a significant voltage which is then logged.

If you don't have a UV lamp then any old UV LED wired to a couple of AA batteries will do. You can test this with office issue A4 white paper, all of which contains OB, as a control use a paper banknote which does not, and your cotton swabs. The cotton bud doped with Tinopal (on the far right in my photo) fluoresces in much the same way as A4 paper does. My cotton buds are formed on to mauve coloured plastic sticks, by the way, that hue has nothing to do with the UV LED!
 

Attachments

  • DIYdetector.jpg
    DIYdetector.jpg
    106.1 KB · Views: 12
  • CottonWoolTester.jpg
    CottonWoolTester.jpg
    91 KB · Views: 15
  • UVlampTest.jpg
    UVlampTest.jpg
    63.6 KB · Views: 15
  • CottonBuds.jpg
    CottonBuds.jpg
    98.2 KB · Views: 15

darklord

Member
Clever little detector/logger, Stuart! As mentioned earlier in the thread I've used OB method for many tests - had a few misfires now and again, but 90% happy with the method and have successfully repeated a test over a 3km drainage route, and most recently a 4km one. (a fluorometer would be nice to know exactly how long the dye took to get through, but expense etc...)

Your last photo in that sequence shows the cotton bud 'Fluorescein' glowing green under UV light. So while fluorescein doesn't fluoresce in the same way OB does, you're suggesting it's still detectable on cotton under UV light?
 
Top