Abstract: A spectrometer includes a light source, a fiber optic bundle with a first and second leg, where the first leg has more fibers than the second leg, a flow cell, focusing optics, a disperser, and a detector. The spectrometer may also include a mask and system electronics to control the spectrometer. The spectrometer allows for simultaneous dual analysis of a reference and sample beam and minimizes errors and attenuations in the signals. The elimination of mechanical moving parts and control of attenuation losses enables less sophisticated control electronics to be utilized.