Zainab,

Depending on the other liquid, and the presence of any solid particles, wouldn't a red LED and a photodiode be sufficient?

Dear James,

The other liquid is water and there is no solids in it.

this is why I am asking if I have PIV in my current lab that would be very easy but because it is only image analysis so I asked if anyone know any new equipment portable that I can use.

Thank you very much dear.

Hello Zainab,

I could imagine that a pulsed LED and a photodiode with an operational amplifier (and perhaps a red filter) would be a very portable device. Log to an Arduino, power by a battery, and I think that a few-% accurate measurement could be made.

Something like:

http://physicsopenlab.org/2016/04/15/diy-fluorometer-for-dna-concentration/

(complex)

or

http://web.colby.edu/ch331public/files/2011/08/A-SIMPLE-PHOTOMETER-2015.pdf

(too simple)

If you have a keen student, I think that a few days would be all that's needed to lash something together that would work quite well. It depends on how quickly you need this, and how accurate/portable/robust it needs to be.

I confess, I am not sure what 'PIV' means.

Thank you very much dear

I used PIV (Particle Image Velocimetry) in Chemical engineering in Birmingham University. But because I am not in Birm at the moment and I need to do some experiment this is why I am asking.

Best wishes,

Zainab

hello dear colleagues,

PIV systems are as far as I know, mostly used with solid contaminants or liquid droplets in gases. For a mixture of fluids especially if one has a different opacity or refraction index to the other indeed optical transmission methods are usually adopted.

It is much easier and much cheaper to use a windowed tube with an optical sensor on one side and a photodiode on the other even when dealing with low quantities of solid contaminants in gases. Variations in light intensity can be correlated with contaminant concentration.

As a sidenote the P in PIV stands for "particle" therefore if the contaminant is in a different material state (liquid or solid) to the gaseous or liquid flow media the laser can accurately get reflected on its surface and the PIV simply counts the number of reflections in a precise volume to guess average speed of the flow (and possibly contaminant quantity but as a consequence). If the contaminant is in the same material state PIV is generally not used (no good for gases mixed with other gases, or liquids mixed together, etc but ok for dust in gases, liquid droplets in gases ,and might work for dust in liquids).

Also PIV systems have a limited range of optimal concentrations of particles they like to work with - and are generally aimed at flow speeds not particle count.

The most common alternate detection methods can be very different by principle - like chemical sensors, impedance methods, or the already mentioned optical transmission methods. You can also try photospectrometry methods if you have the hardware avaliable. You can try spectral absorbtion methods also.

So -go for the low-tech but fairly accurate approach : Jerry's choice.Or go full scientific on the problem- use a white calibrated spectrometry light source or calibrated intensity light projector and as a sensor a calibrated and accurate luxmeter, conduct the experiment in a pitch-black room, read data in water-only flow then calibrate your flow sensor using known concentrations of the blue dye in water.

Good luck and one recommendation for mr.Jerry- optical transmission methods are the best and open-source hardware is indeed very affordable therefore easily repeatable if not extra-accurate.

Thank you very much dear Your answer is really helpful.

Best Wishes,

Dr. Zainab Al-Sharify