I am wondering if there is anything in the literature that can tell me what is the molar absorptivity (i.e. molar extinction coefficient) of aqueous sulfuric acid at a given wavelength (in my case, I am interested in $\lambda_\mathrm{max}(\mathrm{ferroin}) = \pu{508 nm}$).

In addition, is there a good resource in the literature to look up these values for common substances? I haven't yet been able to find anything of the sort.


1 Answer 1


I never ran into uv absorption data for (aqueous) sulfuric acid and I doubt that there is any absorption at $\lambda$ = 508 nm.

There is an old paper by K. F. Palmer and D. Williams in Appl. Optics, 1975,14, 208-219 (DOI) on the optical properties of sulfuric acid droplets with respects to the composition of clouds on Venus and a more recent one from the group of J. B. Burkholder in Phys. Chem. A, 2003, 107, 1112-1118 (DOI) on Vibrational and Electronic Spectroscopy of Sulfuric Acid Vapor. Both, while interesting and therefore mentioned here, are not relevant for your experiment.

My suggestion is simple:

Measure your ferroin sample in aqueous sulfuric acid (or whatever solvent is required) and use the same solvent as a blank. Most spectrometers will automatically perform the subtraction of the blank from your sample!

Concerning a (free) source of UV-vis absorption data, there is the NIST Chemistry WebBook.


Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.