Abstract: The present invention is a cuvette assembly for use in optically measuring at least one characteristic of particles within a plurality of liquid samples. The cuvette assembly comprises a main body having internal walls and external walls, and a plurality of cuvettes within the main body at least partially being defined by the internal walls. Each of the plurality of cuvettes has a liquid-input chamber for receiving a respective one of the plurality of liquid samples, a filter, and an optical chamber for receiving a respective filtered liquid sample caused by passing the respective one of the plurality of liquid samples through the filter. Each of the optical chambers includes an entry window for allowing transmission of an input light beam through the filtered liquid sample and an exit window for transmitting a forward scatter signal caused by the particles within the filtered liquid sample.

Abstract: An instrument determines a concentration of bacteria in a plurality of fluid samples, and comprises a housing, a rotatable platform, a plurality of fluid containers, a light source, a sensor, and a motor. The rotatable platform is within the housing. The fluid containers are located on the rotatable platform. Each fluid container holds a corresponding one of the plurality of fluid samples, and has an input window and an output window. The light source provides an input beam for transmission into the input windows of the fluid containers and through the corresponding fluid samples. The input beam creates a forward-scatter signal associated with the concentration of bacteria. The motor rotates the rotatable platform so that the input beam sequentially passes through each fluid sample. A sensor within the housing detects the forward-scatter signal exiting from the output window associated with the fluid sample receiving the input beam.