The ability to measure concentrations of a molecule underpins the building of a comprehensive knowledge of the pharmacokinetics of a pharmaceutical or nutraceutical, which is essential for the determination of its safety and efficacy. In this study a sensitive and selective method was developed for the analysis of a natural organic molecule, Compound X, in rat plasma. In this study, a natural organic molecule, Compound X, was investigated for its recovery from rat plasma. This molecule was purified to 99%+ levels for development of a sample preparation and bioanalysis protocol. Compound X is known to bind to haemoglobin and has high potential for protein binding. A bioanalysis method involving reverse-phase UHPLC-DAD-MS was developed to facilitate the quantitative analysis of Compound X. Compound X was spiked into the plasma alone and in combination with the internal standard, Allyl phenyl sulfone. Extraction of Compound X from plasma was achieved through protein precipitation with acetonitrile, collection and reduction of the supernatant, and reconstitution before analysis. Recovery of both Compound X and the internal standard was monitored, along with matrix effects, using the UHPLC-DAD-MS. Recovery of Compound X was achieved with minimal matrix effects allowing quantitative measurements of the molecule extracted from rat plasma. Issues including solubility, stock stability and suitable internal standard were overcome. The developed bioanalysis method was an in–house first and will underpin further development to support preclinical pharmacokinetics and toxicokinetics in efficacy and safety studies, and subsequent clinical studies.