Abstract: A multiple-channel spectrometer assembly for analyzing a plurality of sample flows. The assembly includes a plurality of spectrometer channels, each fluidly connectable to a respective one of the sample flows. Each channel has a sample inlet and a sample outlet. A spectrometer module is optically coupled a light outlet portion of the light source. The spectrometer module has an optical inlet to receive light from the light source. A flow cell assembly is positioned between the light source and the spectrometer module, and the flow cell assembly has a flow passageway in fluid communication with the sample inlet and sample outlet. The flow passageway is configured to receive a sample flows therethrough so the light from the light source passes through the sample flow prior to being received by the spectrometer module for analysis of the light absorption profile of the sample.