Abstract: The disclosure is directed to a spectrophotometric measuring device equipped with a plurality of channels which automatically analyze many specimens with different testing items in a short period of time for application in biochemical automatic analysis or the like.

Abstract: A dilution pipetter comprising a diluent sucking probe, a sample probe for sucking and discharging a liquid sample, a diluent discharging probe disposed adjacent to the sample probe, a plunger pump of small plunger diameter selectively communicating with the diluent sucking probe or the sample probe by a first switching means, and a plunger pump of large plunger diameter selectively communicated with the diluent sucking probe, the sample probe or the diluent discharging probe by a second switching means. The dilution pipetter is useful as, e.g., an element of a clinical chemistry analyzer which is used to conduct numbers of reactions for small quantities of a liquid sample such as serum of the warm blooded animal including humans.

Abstract: A spectrophotometer comprising means for producing electrical signals Er and Es corresponding to reference and measuring beams, respectively; means for multiplying the value Es by a factor k to produce an electrical signal corresponding to the value kEs; means for controlling said signal producing means so as to keep the value (Er + kEs) constant; and means for producing an electrical signal corresponding to the value (Er - kEs), whereby minute changes of the absorbance of a sample can be accurately measured without logarithmic conversion.

Abstract: Densitometer for quantitative determination of the content of a sample spot on a TLC plate or the like, wherein dualwavelength zigzag scanning is conducted on the spot. Light reflected and transmitted by the sample is received by photometers, and compensation based on Kubelka-Munk's theoretical equations is made on the photometer output so that the output is substantially proportional to the quantity of the substance in the spot being scanned.