CUVETTE POSITIONING DEVICE FOR OPTICAL ANALYTICAL RATUS

CUVETTE POSITIONING DEVICE FOR OPTICAL ANALYTICAL APPARATUS Cuvette positioning apparatus for use in a spectrophotometer adapted for comparing first and second material samples includes a carrier in which cuvettes to be alternately analyzed are arranged end-to-end. The carrier is reciprocated along a vertical axis to expose the cuvettes in alternation to the monochromatic beam of the apparatus. The rate of reciprocation is selected to avoid cavitation of the samples, and a sinusoidal drive arrangement increases the exposure time of the samples to the light beam and minimizes transit time for optimum measurement efficiency. Circuitry responsive to synchronizing signals derived from the drive arrangement is utilized to form an output signal indicative of the difference in measured characteristics between the samples.