The Analysis of Film-Forming Amines - Methods, Possibilities, Limits and Recommendations

摘要

Treatment concepts of the water-steam cycle based on film-forming amines are attracting increased attention due to their advantageous properties. This type of treatment requires a reliable and, under field conditions, simple analytical method for the determination of the free (not surface bound) proportion of the amine. This is not a trivial task because of the intrinsic physicochemical properties of film-forming amines. An overview of common determination methods on the market is given. BKG Water Solutions has studied the Bengal rose method described in the literature and performed detailed optimization and validation work. Recommendations are given regarding the sampling and rinsing procedures and the necessary quality of the dye. The detection sensitivity of film-forming amines depends on their chemical structure and exceeds the detection sensitivity of typical components of the sample matrix by several orders of magnitude. Interferences caused by the sample matrix exist in the form of increased measurement values but are acceptable under practical conditions. The method has a detection limit of about 0.1 mg · L~(-1) free film-forming amine; an optical pathlength of 5 cm is advantageous. The method has also been validated using two independent methods based on different measurement principles and is currently being developed into an online determination tool by BKG Water Solutions.