Hello,

please give us (the answerers) the typ of your Camag TLC scanner p.e Nr. 4 or older.

For Nr. 4 see

https://www.camag.com/product/camag-tlc-scanner-4

and order the Infos about it.

027.6200

CAMAG® TLC Scanner 4

for the densitometric evaluation of TLC/HPTLC plates, spectral range 190 to 900 nm, plate sizes up to 20 x 20 cm, absorbance and fluorescence mode, CAMAG visionCATS controlled.

During TLC investigations with fluorescence, a degradation of compounds can occur on Silicagel 60 and traces of TLC eluent.

What a kind of phenolic products are you using?

Concerning the part of your question:

How to fix this problem and can TLC scanner in fluorescence mode reach single molecule detection or what is wrong?

Please compare the possibility of your scanner with the possibility of single molecule spectrometer!!

see :

https://en.wikipedia.org/wiki/Single-molecule_experiment

Good luck

JRG

Hi Sara,

Is it possible the observed decrease in fluorescence peak area may be due to the aggregation caused quenching (ACQ)? Did you notice the absorbance also changing with respect to the fluorescence spectra?

Jean Rene Grezes

yes I am using Camag TLC scanner 4 ,working on natural phenolic compounds and how degradation can affect readings if I am preparing fresh stock solutions every time and measuring readings instantly after developing plates and air drying the developing system (I also tried oven drying of eluent with the same problem).

I compared it with Agilent Cary eclipse spectroflorimeter, unfortunately it couldn't even detect concentrations in low nanogram range( TLC scanner is far more sensitive)

Chathura Abeywickrama

yes absorption mode gave the same behavior as florescence going up and down in the same way. how to avoid this problem???