ESI-FT-ICR MS in the identification and characterization of tetrameric acids (ARN) in petroleum and naphthenates with minimal sample preparation

Naphthenate deposits are a major obstacle in ensuring an economic and successful flow in the production and processing of crude oil. The formation of these deposits depends mainly on a specific group of high molecular weight tetrameric acids, sometimes called ARN. Among the challenges of identifying and characterizing the ARN of this complex matrix, we propose the use of a new analysis methodology for identifying these species in oil samples and naphthenate deposits with minimal sample preparation. Such methodology is based on an unconventional approach to the negative-mode electrospray ionization technique, combined with high resolution and precision mass spectrometry. The methodology proved to be promising and advantageous, since it requires a simpler sample preparation and a reduced consumption of reagents and analysis time. With good feasibility of application to identify the nature of deposits and to estimate, in an initial phase, the potential for inorganic scale and the need for oil treatment in production units.