It is not so easy but density of the suspension can make an indirect measure of solid content. Another option is to follow liquid phase concentration by refractive index, for instance.

Hi,

did you consider IR or Raman measurement of the concentration in solution?

To characterize the solid state I would suggest techniques like Mettler Toledo / Lasentec PVM or FBRM.

regards,

Michael

Thanks Silas, refractive index is an option only if the crystals are large enough to affect the brix of the solution - however it is an option indeed.

Thanks Michael, haven't been exposed to those techniques before, will definitely have a look at them.

What about ordinary turbidometry at several wavelengths? Would need calibrating though (the standard assay for lysozyme is still turbidometry of suspensions of cells of Micrococcus lysodeikticus)

Thanks Michael, my team and I are currently looking at a turbidity technique to quantify the concentration of sugar crystals - turbidometry seems to be the non-intrusive way.

I was also going to suggest the use of some sort of turbidity measurement.  This would be easily implemented; however I think you would have to consider not only particle number concentration but the size of the particles that you have at the location of the measurement too.

One other option could be to try and incorporate a FBRM probe in to your experimental setup?  This would provide a  more quantitative measurement as it would allow simultaneous measurement/estimate of particle size and number.  This would rely on the ability to borrow/use an FBRM probe with your setup.

Thank you (@ Michael and Martin), going to test out the use of a turbidity device soon, it seems to fit this application nicely.

It is common technique to use online microwave probe to measure total solids content (solids in crystals plus solids in solution) and process refractometers (from K-PATENTS Oy., Finland) to measure solids in solution. From the difference solids in crystals can be calculated.

Regards

L. Rózsa

[email protected]