CORROSION INHIBITORS QUALITY CONTROL BY SPECTRAL METHODS

Digital technology for quality control of field reagents based on a numerical algorithm for processing digitized Raman spectra (Raman) and infrared (IR) spectra has been developed. The technology was tested on samples of field corrosion inhibitors. To make a decision on the conformity of the quality of the test reagent, the width of the acceptance limit was calculated for the conditions of different values of the specific risk of making a false negative decision. Methodological basis for calculations is in accordance with standards ILAC-G8:09/2019, ISO/IEC 17025:2017, GOST R ISO 10576-1. The absorption bands in the IR spectra and emission bands in the Raman spectra of the reagents are attributed to vibrations of the functional groups of the active ingredients of corrosion inhibitors (imidazolines, amidoamines) used for commercial reagent production. Using numerical algorithms, an analysis of changes in the intensity of spectral bands characteristic of functional groups of active substances in samples of commercial reagents was carried out. A methodological basis for determining the quantitative content of amidoamine nitrogen by increasing the intensity of the bending vibration line of the –NH group was developed and tested. The theoretical content of amidoamine nitrogen in corrosion inhibitors, calculated on the basis of the component composition data, is in good agreement with the experimental results.The linearity of the dependence of the intensity of the line in the Raman spectra of corrosion inhibitors on the nitrogen content of amidoamines allows us to take as a basis the described methodological approach for creating a technique for the quantitative determination of amidoamine nitrogen using the additive method.The technology has prospects in expanding the scope of applicability and conducting examination of reagents for the qualitative and quantitative content of active substances, introducing the technology into the practice in oil service and oil producing companies.