Application of cation-exchange chromatography for quantification of some ethanolamine degradation products in the natural gas sweetening solution

Abstract

BackgroundAmine degradation products are very important for industrials not only leads to amine losses but also contribute to operational problems such as high corrosion effects. In this research, a new quantitative method has been developed for the analysis of 2-methylaminoethanol (MAE) and tris(2-hydroxyethylethyl)ethylenediamine (THEED) in the diethanolamine solution by cation-exchange chromatography. MethodsThe mobile phase was optimized for the interference-free determination of THEED and MAE. For THEED, the final composition was included 8 mmol L−1 HNO3 and 15% (v/v) acetonitrile. The linear range of the calibration curve was achieved in the range of 0.5 to 1000 ppm with the correlation coefficient of 0.9998. The relative standard deviation was 3.89%. Also, the mobile phase was optimized for MAE determination. The optimal composition was 1.45 mmol L−1 of HNO3, 0.15 mmol L−1 of 18-crown-6, and 3.4 mmol L−1 of dipicolinic acid. The mobile phase also was contained 0.75% (v/v) of acetonitrile. Significant FindingsThe linear range of the calibration curve was from 0.1 to 200 ppm with a correlation coefficient of 0.9999, and the relative standard deviation is 0.46%. Very low detection limits including 0.03 and 0.17 ppm were found for MAE and THEED respectively. Acceptable precisions, below the 3.89%, were accomplished by the method. The proposed method was used for the determination of desired compounds in the real natural gas sweetening solution.