Unfortunately, FTIR will only give qualitative and not quantitave analysis. The species in the solution will be identified. Thus FTIR analysis of the blank will only give you the states of the corrdant and metal ions. They may have interacted in one manner or the other. This naturally will depend on if the experiment is carried out with inorganic or organic corrodent. Yeah corrosion rates can be monitored with metal ions concentration in the corrodent but not with FTIR. You may use other techniques to monitor the metal ion concentration. AAS for example.

Dear Makanjuola Oki

Thanks for contributing in my discussion. You know, the purpose of FTIR analysis in the samples taken from the test solution is to investigate the changes which could happen in the solution in the absence and presence of different inhibitor concentrations. To summarize the discussion, i would say this proposed method is to assess the behavior of the test solution and not the electrode in order to investigate change in the chemistry of the electrolyte in the vicinity of the working electrode.

In the presence of adequate concentrations of inhibitor, there would be less Fe2+ ions in the vicinity of the working electrode which results in the changes on the peaks of FTIR spectra and gives us valuable data to interpret from the chemistry point of view.

Regarding ion concentrations in the solution as you said there are several methods but the purpose of my discussion is to investigate the behaviour of the electrolyte especially the behavior of functional groups including hetero atoms which play the main role in the formation of a protective film on the surface of the metal in corrosive media.

Dear Dr. Askar Soltani ,

I confirm what was said in our previous discussion. The FT-IR technique is very helpful, especially for organic inhibitors (or those with specific chemical bonds). With an accessory (eg specular reflectance) on which you place the sample, you can monitor the presence of inhibitor (and broadly the quantity). I tell you this because the presence of inhibitor must guarantee a homogeneous and fairly stable film, otherwise, if present in the form of spots it can create more damage than advantages. In the work I was doing, I had an inhibitor deposited on different samples using different concentrations that I characterized with FT-IR and other surface (e.g. AFM) or electrochemical (EIS) analysis. Subsequently I exposed the different series of "protected" samples to the aggressive environment and I redid characterizations on the samples (generally with the same techniques) to monitor the inhibitor presence, homogeneity and protection of the substrate against the corrosive phenomena.

Good work and my best regards, Pierluigi Traverso