Abstract: A device and method for measuring optical properties of a sample are provided. The device comprises a housing surrounding a flow-through flow-cell having a sample inlet positioned proximate to a first end of the flow-cell and a sample outlet positioned proximate to a second end of the flow-cell and a sample chamber positioned between the sample inlet and the sample outlet. A plurality of excitation sources are positioned on the housing and are incident on a sample in the flow-cell. At least one excitation source has a wavelength that is different from the other excitation sources. At least one fluorescence emission detector, which detects a continuous broadband spectrum of emission wavelengths, is positioned in an operable relationship to the flow-cell. At least one signal interrogation system, which interprets a continuous fluorescence emission spectrum, is positioned in an operable relationship with each detector.