Hi Mr Ashiegbu,

I suggest you to use a solvent with lower UV cut off value than operational wavelength in your experiment. For example, if you want to measure absorbance at 254 nm, you should use a solvent with UV cut of below 254 nm, it can be 200 or 190.

You can see the uv cut off table for some common solvent as following:

https://www.utsc.utoronto.ca/~traceslab/UV_Cutoff.pdf

Regards

Mr. Ashiegbu,

You should use only solvent.

Mr. Ashiegbu,

I agree fully with the above answers (Dion/Ivanova).

At first , give us please the following Infos:

-Kind of UV-Vis spectrometer e.g single or dual beam or diode arrays.

- If you have an old spectrometer in your uni, please ask your supervisor if the light source Vis and light source UV are not too old and diffraction grating and mirror are OK.

- What a kind of cuvette are you using (quartz or plastic….)?

- Please note that your cuvettes (reference and sample cuvette (p.e. for dual beam) MUST BE CLEAN AND DRY!!

- The quality of the solvent must be "spectroscopic quality" (see details if you use Aldrich ….) and must be pure and dry.

- The cut off of your cuvettes and your solvent is important.

- You must record your spectrum in sealed cuvettes. Ethylbenzene is volatil.

- Please note that the kind of solvent can slightly influence the shape and position (s) of lambda max p.e isooctane or methanol or ethanol.

-What do you mean with:

/solvent do I need to calibrate the UV-Vis?

If you want to calibrate your spectrometer, please read:

How can I calibrate a UV-Vis spectrophotometer? - ResearchGate

https://www.researchgate.net/.../How_can_I_calibrate_a_UV-Vis_...

Diese Seite übersetzenUV-Visible Spectroscopy ... 756 UV-VIS Spectrophotometer.jpg673.91 KB ... document detailing how can calibrate the UV-Visible Spectrophotometer. Finally ….

Good luck

JRG

I send you the pdf file of the previous cited article about UV-Vis calibration (Yesterday).

JRG

Thanks guys, I have seen and fixed my error. My mistake had to do with the concentration of my ethylbenzene. Some machines are quite sensitive and so require the tiniest amount in comparison with the solvent. Thanks guys for your help and time.