check the attached files and I hope to be useful to you

http://www.biochrom.co.uk/content/1/91/glossary-of-uv-vis-spectrophotometry.html

For quantitative analysis you can directly use a molar extinction coefficient for toluene. For example, its log epsilon(261 nm) = 2.43

http://webbook.nist.gov/cgi/cbook.cgi?ID=C108883&Units=SI&Mask=400#UV-Vis-Spec

Mohamed

your 35.pdf concerns toluene as a solvent; and the cut-off wavelength at which NO light comes thru the solvent?

thank you  very much Stephen R Lantz, Mohamed A Elbagerma and Igor Dubey for your valuable comments.

Yohan,

you should be aware that at least in water toluene has a high tendency to evaporate. Therefore you should use air tight cuvettes and measure just after filling the cells.

Mr. Jayawardana,

Please find as atachment the quantitation steps, using UV-VIS specroscopy

I think this link is useful, 

http://www.instanano.com/characterization/theoretical/concentration-calculation-from-uv-vis-absorbance/