I got an sample with known Absorbance at 285nm which is 0.689 (got it from CoA).

Then I transferred it to another container to check whether it is feasible for toluene. I collected toluene sample from the container after rinsing the container with the toluene.

I tested the toluene sample with my in-house UV-Vis at 285nm, the result i got is vary from the CoA. I got 0.9 at 285nm, ultra pure water as blank.

I tried to use ethanol as blank but the absorbance I got for the toluene sample at 285nm is also about 0.9.

Even I take the toluene sample directly from the original bottle without passing through any other container, the absorbance i got at 285nm is also about 0.9

Is there anything to do with the UV cut off ?

Please advise. Thank you