When biological components are separated and analyzed by use of biological samples of blood or the like, high-performance liquid chromatography apparatus (HPLC apparatus) using high performance liquid chromatography (HPLC) are widely used (e.g., refer to Patent Document 1).
As shown in FIG. 13, a general HPLC apparatus 9 is configured to prepare a sample containing biological components in a sample preparation unit 90 and then to introduce the sample into an analytical column 91 to thereby adsorb the biological components to a filler of the analytical column 91. When glycated hemoglobin is measured by using whole blood as a sample, red blood cells collected from whole blood are hemolyzed and then a biological sample in a state in which the laked blood is diluted is introduced into the analytical column 91. On the other hand, a biological component adsorbed on a filler is eluted by supplying an eluent from an eluent bottle 93 to the analytical column 91 by a liquid feed pump 92. The eluent including the biological component from the analytical column 91 is introduced into a photometry mechanism 94, where the biological component is analyzed by continuously measuring the absorbance of the eluent including the biological component.
As shown in FIG. 14, the photometry mechanism 94 radiates light from a light source 97 while the eluent including the biological component flows through a path 96 of a photometry cell 95 and receives a transmitted beam at that time in a light receiving section 98. The wavelength of light received in a light receiving section 98 is selected in an interference filter 99, while a signal of an output level corresponding to the amount of light received is output from the light receiving section 98. Since the photometry of an eluent in the photometry mechanism 94 is continuously executed, the relationship between the elution time and the amount of light received (absorbance) is obtained as a chromatogram shown in FIG. 15.
The HPLC apparatus 9 further calculates the total amount of hemoglobin based on a chromatogram that is a change with the lapse of time of absorbance and also calculates the glycated hemoglobin concentration as a proportion occupied by the amount of glycated hemoglobin in the total amount of hemoglobin (part shown by a cross hatching in FIG. 15).
However, the amount of dissolution in an eluent of a gas such as oxygen varies depending on the temperature of the eluent. Therefore, when the temperature (environmental temperature) outside the apparatus varies or the biological component is analyzed in a state at a different environmental temperature, the state of a dissolved gas in an eluent (amount of dissolution) is different. Hence, when the dissolved oxygen concentration in an eluent varies along with the variation of environmental temperature, or the like, the ratio of the amounts of oxyhemoglobin and deoxyhemoglobin in hemoglobin varies. In addition, even in a biological sample introduced into the analytical column 91, the ratio of the amounts of oxyhemoglobin and deoxyhemoglobin in hemoglobin can vary at each measurement of each time.
On the other hand, a sample is used that has a relatively large amount of oxygen by dilution of laked blood, as a biological sample introduced into the analytical column 91, and therefore 415 nm that is the maximum absorption wavelength of oxyhemoglobin is adopted as a measurement wavelength in the photometry mechanism 94. Thus, under environments in which the change in environmental temperature is large, or the like, the ratios of the amounts of oxyhemoglobin and deoxyhemoglobin vary, whereby precise measurements become difficult when they are measured at the same wavelength.
Patent Document 1: Japanese Patent Laid-Open No. 7-120447