US 7,626,698 B2Granted

Method of analysis in optical measurements

AssigneeShimadzu Corporation

InventorNaoji Moriya

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Abstract

The method of the present invention generates a regularly lined electric field inside a container 1 retaining a sample formed by dispersing particle groups in a liquid by a voltage being applied to an electrode pair 2 provided in the container 1, generates a diffraction grating by a density distribution of the particle groups in the sample inside the container 1, and when acquiring a diffusion coefficient of particles from a temporal variation of intensity in a disappearing process of a diffracted light obtained by irradiating a beam of light to the diffraction grating generated by the density distribution of the particle groups, performs a particle size analysis of the particle groups by using an approximate analysis expression of a diffracted light attenuation, I(t)=∝exp[−2q2Dt] which uses q=2π/Λ defined by a particle concentration modulation period Λ in the density distribution diffraction grating of the particle groups, and the Einstein-Stokes relation. And if particle groups having a known particle size are dispersed in a liquid to be measured and similar measurements are performed, viscosity analysis of the liquid to be measured can be performed.

Claims10

Dependent claims

A method of analysis in an optical measuring method,

wherein the optical measuring method uses an apparatus comprising:
a container that retains a gel sample or a liquid formed by dispersing particle groups movably in a medium;
a power supply that generates a voltage with a predetermined pattern including a direct current, frequency modulation and voltage modulation, or pattern capable of being arbitrarily set;
an electrode pair provided in the container, which generates a regularly lined electric field distribution in the container by applying the voltage from the power supply;
a control means that controls application of the voltage from the power supply to the electrode pair to control generation of a diffraction grating generated by density distribution of particle groups in the sample inside the container generated by dielectrophoretic force acting on the particle groups and disappearance thereof;
a light source that irradiates beam of light to an area where the diffraction grating is generated inside the container;
and
a photo-detector that detects diffracted light of the beam of light by the diffraction grating,
the optical measuring method performing a particle size analysis of the particle groups in the sample from a temporal variation of intensity of a diffracted light detected by the photo-detector, wherein
the method of analysis, comprising the step of:
using the Einstein-Stokes relation,
D=KBT/3πηd,
wherein KB is a Boltzmann constant as a diffusion coefficient, T is an absolute temperature of the particle-dispersed liquid to be measured, η is a viscosity of the particle-dispersed liquid or the gel to be measured, and d is a particle size of the particles to be measured, and
an approximate analysis expression of a diffracted light attenuation,
I(t)=∝exp[−2q2Dt],
which uses q=2π/Λ defined by a particle concentration modulation period Λ in the diffraction grating generated by density distribution of the particle groups
to obtain the particle diameter d.

14 more elements

A method of analysis in an optical measuring method,

wherein the optical measuring method uses an apparatus comprising:
a container that retains a gel or a sample liquid formed by dispersing particle groups with known particle size movably in a medium;
a power supply that generates a voltage with a predetermined pattern including a direct current, frequency modulation and voltage modulation, or pattern capable of being arbitrarily set;
an electrode pair provided in the container, which generates a regularly lined electric field distribution in the container by applying the voltage from the power supply;
a control means that controls application of the voltage from the power supply to the electrode pair to control generation of a diffraction grating generated by density distribution of particle groups generated by dielectrophoretic force acting on particles in a suspension inside the container and disappearance thereof;
a light source that irradiates beam of light to an area where the diffraction grating is generated inside the container;
and
a photo-detector that detects diffracted light of the beam of light by the diffraction grating,
the optical measuring method performing a viscosity analysis of the sample liquid and gel from a temporal variation of intensity of a diffracted light detected by the photo-detector, wherein
the method of analysis, comprising the step of:
using the Einstein-Stokes relation,
D=KBT/3πηd,
wherein KB is a Boltzmann constant as a diffusion coefficient, T is an absolute temperature of the sample liquid or gel to be measured, η is a viscosity of the sample liquid or gel to be measured, and d is a known particle size of the particles, and
an approximate analysis expression of a diffracted light attenuation,
I(t)=∝exp[−2q2Dt],
which uses q=2π/Λ defined by a particle concentration modulation period Λ in the diffraction grating generated by density distribution of the particle groups
to obtain the viscosity η of the sample liquid or gel.

14 more elements

Dependencies are inferred from the claim text.

Facts

Application: 12/281,097Filed 28 Feb 2006
Published: US 2009/0128809 A121 May 2009
Granted: 1 Dec 2009
Term ends: Not estimatedThe source records don’t support an estimate.

Classification5 codes

G01N 15/0211
By optical means: investigating a scatter or diffraction pattern
G01N 21/4788
Scattering, i.e. diffuse reflection: diffraction
G01N 2011/008
Determining flow properties indirectly by measuring other parameters of the system: optical properties
G01N 2015/0216
Investigating a scatter or diffraction pattern: from fluctuations of diffraction pattern