Film-forming amine products (FFAP) are frequently used as corrosion inhibitors in steam-water systems. To have a better understanding of their behavior in the treated system, a liquid chromatography coupled to the high-resolution mass spectrometry (LC-HRMS) method was developed. This method enabled the concurrent targeted quantitative analysis of the film-forming amine oleyl propylenediamine (OLDA) and the nontarget screening (NTS)-based analysis of potential degradation products of FFAP or other organic matter in the system. The method was applied to samples collected from an FFAP-treated industrial steam-water system. OLDA was detected at a concentration of 0.027 mg/L after the FFAP dosing in the low-pressure steam drum. A feature (a combination of mass-to-charge ratio and retention time associated with a signal intensity) prioritization workflow was designed and applied to the NTS results to focus on the potential thermal degradation products of FFAP that could affect the studied steam-water system. Six features were prioritized from a total of 4596 detected features. Structural elucidation of these features was attempted based on mass spectrometry fragmentation data. One of the prioritized features was successfully identified as 2,2'-(tridecylimino)diethanol, presumably a degradation product of the FFAP emulsifier. Because of the chemical structure of the molecule, 2,2'-(tridecylimino)diethanol was considered as noncorrosive to the system. Overall, the developed LC-HRMS method facilitated the efficient analysis of OLDA with a limit of quantification of 0.002 mg/L and a comprehensive monitoring of organic matter across the steam-water system, including potential degradation products of the dosed FFAP.