| 摘要 |
PURPOSE:To enable a sample density changing over a wide range to be continuously measured by changing a cell length so that an absorbancy is kept constant. CONSTITUTION:After being inputted to and amplified by an amplifier 40, the output signals of photodetectors 34 and 38 are logarithmically converted and a difference A between an absorbancy at a maximum absorption wavelength and the one at a wavelength at which an absorption is hardly perceived is calculated. A constant absorbancy Aconst is set to the amplifier 40 in advance. When a sample solution 4 is made to flow in a sample cell portion 2 and a measurement is started, since the difference A of the absorbancy inputted to the amplifier 40 changes in accordance with the density of the solution 4, a servomotor 16 is driven by the output signal of the amplifier 40 so that the difference A takes the constant value Aconst. A supporting member 8 is slided via a pinion 18 and a rack 14 to change a cell length L. Thus, the cell length L corresponding to the density of the solution 4 is detected by a voltmeter 22 in a cell length detector 20 and the density C can be calculated from the cell length L. |
