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

Spectrochim Acta A Mol Biomol Spectrosc. 2020 Mar 15:229:117877. doi: 10.1016/j.saa.2019.117877. Epub 2019 Dec 2.

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.