Spectroscopic method and apparatus for measuring sugar concentrations

Claim 2

A spectroscopic method for measuring concentrations of sugars in samples, which comprise s a first step wherein light intensity of a light source (2) in an interferometer (MI) is set at a first prescribed value and outcoming light beams from said interferometer (MI) are emitted into an integrating sphere 9) to irradiate a sample (15) placed at a sample aperture of said integrating sphere (9), a second step wherein diffusely reflected light beams from said sample (15) are detected by a photo detector (10), a third step wherein absorption spectrum of the sugar under measurement at a first depth in said sample (15) is determined by processing electrical signals from said photo detector (10) by a computer (12), a fourth step wherein the light intensity, of the light source (2) in said interferometer (MI) is set at a second prescribed value and absorption spectrum of the sugar under measurement at a second depth in said sample (15) is determined in the same manner as in said first, second and third steps, and a fifth step wherein absorption spectrum of the sugar under measurement at a deeper region between said first and second depths in the sample (15) is determined on the basis of the difference between the respective absorption spectrum determined in said third and fourth steps so that the concentration of the sugar under measurement in said deeper region in said sample (15) can be determined on the basis of said absorption spectrum at said deeper region, the wavelengths for a use for said absorption spectrum being selected from a wavelength band of from 950 to 1,150 nm, from 1,150 to 1,300 nm, or from 1,300 to 1,450 nm.

Claim 3

A spectroscopic method as claimed in Claim 1, wherein said wavelengths for the use for said absorption spectrum comprise three or more in number selected from any one of said wavelength bands.

Claim 4

A spectroscopic method as claimed in claim 1 or claim 2 wherein the sugar to be determined is selected from a group of glucose, saccharose, and fructose.

Claim 5

A spectroscopic method according to any one of the preceding claims wherein the sugar to be determined is a sugar in human blood.

Claim 6

A spectrophotometric apparatus for measuring concentrations of sugars in samples, which comprises an interferometer (MI) for emitting superposed light beams, a controller (1) for adjusting light intensity of a light source (2) which is placed in said interferometer (MI), an integrating sphere (9) for collecting diffusely reflected light beams from a sample (15) placed at said integrating sphere (9), a photo detector (10) for detecting said collected light and converting it into an electric signal, a processing means (12) for processing electric signal from said photo detector (10) so as to compute absorption spectrum of the sugar in said sample (15) to be determined and for determining the concentration of the sugar under measurement on the basis of said absorption spectrum, and a means (13) for selecting optimum wavelengths for a use for said absorption spectrum from a wavelength band of from 950 to 1,150 nm, from 1,150 to 1,300 nm, or from 1,300 to 1,450 nm, said processing means (12) including a means whereby, on the basis of the difference between the absorption spectrum of the sugar under measurement at a first depth in said sample (15) which is computed for light intensity of said light source (2) in said interferometer MI) set at a first prescribed value and absorption spectrum of said sugar at a second depth which is computed for light intensity of said source (2) set at a second prescribed value, the absorption spectrum of the sugar under measurement at a deeper region between said first and second depths in said sample (15) is computed and including furthermore a means whereby, on the basis of said absorption spectrum at said deeper region, the concentration of the sugar under measurement in said deeper region in the sample is computed.

Claim 7

A spectrophotometric apparatus for measuring concentrations of sugars in samples, which comprises an interferometer (MI) for emitting superposed light beams, a controller (1) for adjusting light intensity of a light source (2) which is placed in said interferometer (MI), an integrating sphere (9) for collecting diffusely reflected light beams from a sample (15) placed at said integrating sphere (9), a photo detector (10) for detecting said collected light and converting it into an electric signal, a processing means (12) for processing electric signal from said photo detector (10) so as to compute absorption spectrum of the sugar in said sample (15) to be determined and for determining the concentration of the sugar under measurement on the basis of said absorption spectrum, and a means (13) for selecting optimum wavelengths for a use for said absorption spectrum from a wavelength band of from 950 to 1,150 nm, from 1,150 to 1,300 nm, or from 1,300 to 1,450 nm, said processing means (12) including a means whereby, on the basis of the difference between the absorption spectrum of the sugar under measurement at a first depth in said sample (15) which is computed for light intensity of said light source (2) in said interferometer MI) set at a first prescribed value and absorption spectrum of said sugar at a second depth which is computed for light intensity of said source (2) set at a second prescribed value, the absorption spectrum of the sugar under measurement at a deeper region between said first and second depths in said sample (15) is computed and including furthermore a means whereby, on the basis of said absorption spectrum at said deeper region, the concentration of the sugar under measurement in said deeper region in the sample is computed.