Fourier transform ion cyclotron resonance mass spectrometry has made a significant contribution to the characterization of naphthenic acids in petroleum samples. The characterization of naphthenic acids is of particular interest due to their believed involvement in corrosion and deposit formation, as welt as their toxicity toward aquatic organisms. Analysis of a complex mixture, such as a petroleum sample, can present challenges in terms of data analysis and visualization. A variety of graphical methods for representing the data are evaluated, and the use of a heat map, a method primarily used within molecular biology, is highlighted. An Athabasca oil sands sample was characterized and compounds of the empirical formula CnH2n+O-z(x), where x = 2-5, were observed. The range of oxygen content is of particular relevance in light of other research, which has shown that the total acid number of a petroleum sample is not a reliable method for evaluating the acid content, as not all of the acids are monoprotic.