Dear Venkata Pramod , Thanks for your operation. May be the conc limit of B-L exceeded and for this i think so. My UV-Visible of Shimazdu 1900 model. Could you let me know how much low conc of Cr it works well and can sense ( in my case I injected 50 ppm stock solution. Next I will try lowering this conc for finding adsorption equilibrium.
Lookforward to receiving more answer from the people who got expertise in this filed.
Dear Sir Ahmed Samed
The detection limit for Chromium (VI) with Uv-vis in general in 0.5 to 5 ppm range only as it is an colorimetric method. I am also working with Shimazdu 2600 and for this instrument the maximum limit is 5-6 ppm only as after 5 ppm itself the absorbance exceed from 1. In this case I have taken a calibration curve till 4 ppm. For higher concentration its better to dilute your sample and for final results multiply with the dilution factor.
Regards
Amita
Thanks Amita, for your information. I will try to calibrate within this range.