| abstract |
This disclosure relates to a method for measuring the concentrations of sugars in liquids by the use of near infrared as well as an apparatus for practicing said method. The method comprises a step wherein the absorption spectrum of the sugar under investigation existing at a first depth relatively close to the surface in a sample (15) is computed by using relatively weak power of near infrared, a step wherein the absorption spectrum of the sugar under investigation existing at a relatively deep second depth in the sample (15) is computed by using relatively strong power of infrared, and a step wherein the concentration of the sugar under investigation in the sample (15) is determined by computing the absorption spectrum of the sugar at a different depth between said first and second depths on the basis of the results of measurement in said first and second steps. The wavelengths for the use for said absorption spectrum are selected from anyone of wavelength bands of 950-1,150 nm, 1,150-1,300 nm, and 1,300-1,450 nm. Since, according to this method, wavelengths which are shorter and closer to the visible region than in the prior art are used, the method enables the measuring light beams to penetrate deeper in a living tissue and makes it possible to measure the concentrations of sugars existing in a deeper region non-invasively. |