Advanced direct method to quantify the kinetics of acetohydroxamic acid (AHA) by Raman spectroscopy

Abstract The ligand acetohydroxamic acid (AHA) suffers hydrolysis at acidic conditions. This reaction has been studied for a long time, due to its implications in different applications, by using indirect colorimetric methods. This work shows how Raman spectroscopy can be very useful as a direct technique for measuring the hydrolysis kinetics of AHA, faster, more versatile and easier compared with the indirect traditional UV–Vis method which needs a complex formation with Fe. Thereby, we present a detailed study of the qualitative and quantitative Raman spectra of 1 mol/L AHA and its hydrolysis products. These results enabled us to perform a complete kinetic study of this molecule at different pH ranging from 0.5 mol/L to 4 mol/L HNO3, i.e. not only at excess acidic conditions but also at limiting nitric acid conditions.