Abstract: The present disclosure relates generally to systems and methods for determining the absorption coefficient and the optical density of a fluid as they relate to the wavelength of incident radiation. Specifically, ultraviolet light-emitting diodes (UV LEDs) or the like that emit ultraviolet (UV) radiation or the like are used as sources for irradiating the interior of an integrating chamber that is designed to increase the path length of the radiation through the fluid, thus enhancing the detection limits of the absorption coefficient and the optical density according to Beer's Law.