Measurement method using differential refractometer, differential refractometer using the measurement method, and liquid chromatograph

Patent metadata

Field	Value
Publication number	US-10024789-B2
Application number	US-201415115362-A
Country	US
Kind code	B2
Filing date	Feb 7, 2014
Priority date	Feb 7, 2014
Publication date	Jul 17, 2018
Grant date	Jul 17, 2018

Abstract

A differential refractometer including a measurement section for measuring the diffractive index difference between a sample cell and a reference cell by radiating light on a measurement cell and detecting light which has sequentially passed through the sample cell and the reference cell includes a mobile phase supply section for delivering a mobile phase in a sample introduction channel that is connected to the sample cell. The mobile phase supply section includes a mobile phase container for containing the mobile phase. The inside of the mobile phase container is continuously stirred by a stirring mechanism, and the composition of the mobile phase inside the mobile phase container is made uniform.

First claim

The invention claimed is:

1. A measurement method using a differential refractometer including a sample cell through which a sample solution is to pass, a reference cell for a reference solution, and an optical system configured to radiate light that is sequentially transmitted through both of the sample cell and the reference cell and to detect transmitted light by a photodetector, the differential refractometer being for measuring a refractive index difference between the sample cell and the reference cell by detecting displacement of light which has been transmitted through the sample cell and the reference cell, the measurement method comprising:
supplying a mobile phase to the sample cell;
degassing the mobile phase to be supplied to the sample cell;
calculating an amount of drift in a baseline of a detection signal of the photodetector before measurement of a sample is started;
adjusting a degree of degassing of the mobile phase so that the calculated amount of drift falls within a predetermined range;
injecting a sample into the channel through which the mobile phase is flowing, after adjustment of the degree of degassing of the mobile phase;
radiating light on the sample cell and the reference cell and detecting transmitted light by the photodetector; and
determining the refractive index difference between the sample cell and the reference cell based on a detection signal of the photodetector.

2. The measurement method according to claim 1 , wherein degassing of the mobile phase is performed by supplying a degassing gas to a mobile phase container containing the mobile phase, and change of the degree of degassing of the mobile phase is performed by adjusting an amount of supply of the degassing gas to the mobile phase container.

3. The measurement method according to claim 1 ,
wherein, in a case where a refractive index of the sample cell is given as K1 and a refractive index of the reference cell is given as K2, a direction regarding a drift in a baseline of a detection signal of the photodetector of increase in a refractive index difference (K1−K2) between the sample cell and the reference cell is given as a positive direction, and the direction of reduction in the refractive index difference (K1−K2) between the sample cell and the reference cell is given as a negative direction,
in the adjusting a degree of degassing of the mobile phase, the degree of degassing of the mobile phase is increased to increase the amount of drift in the baseline of the detection signal of the photodetector, and the degree of degassing of the mobile phase is reduced to reduce the amount of drift.

4. A differential refractometer comprising:
a measurement cell including a sample cell through which a sample solution is to pass, and a reference cell for a reference solution;
a sample introduction channel, connected to the sample cell, for introducing a sample into the sample cell together with a mobile phase;
a measurement section including a light source for radiating light toward the measurement cell, and a photodetector for detecting light which has passed through the sample cell and the reference cell;
a mobile phase supply section, including a mobile phase container for containing a mobile phase, for supplying the mobile phase to the sample cell through the sample introduction channel;
a degassing device for degassing the mobile phase inside the mobile phase container; and
a control section for capturing a detection signal obtained by the photodetector from the measurement section, and for controlling operation of the degassing device based on the detection signal,
wherein the control section includes drift amount setting means for setting a target range of an amount of drift in a baseline of the detection signal of the photodetector, drift amount calculation means for calculating the amount of drift in the baseline of the detection signal before measurement of a sample is performed, and degassing degree control means for adjusting a degree of degassing of the mobile phase by the degassing device before measurement of the sample is performed, in such a way that the amount of drift calculated by the drift amount calculation means falls within the target range set by the drift amount setting means.

5. The differential refractometer according to claim 4 , wherein the degassing device is a degassing gas supply section including a supply source for supplying a degassing gas into the mobile phase container, and an adjustment mechanism for variably adjusting an amount of supply.

6. The differential refractometer according to claim 5 , wherein the degassing gas is helium gas.

7. The differential refractometer according to claim 4 ,
wherein, in a case where a refractive index of the sample cell is given as K1 and a refractive index of the reference cell is given as K2, a direction regarding a drift in a baseline of a detection signal of the photodetector of increase in a refractive index difference (K1−K2) between the sample cell and the reference cell is given as a positive direction, and the direction of reduction in the refractive index difference (K1−K2) between the sample cell and the reference cell is given as a negative direction,
the degassing degree control means increases the degree of degassing of the mobile phase if the amount of drift calculated by the drift amount calculation means is lower than the target range, and reduces the degree of degassing of the mobile phase if the amount of drift calculated by the drift amount calculation means is higher than the target range.

8. A liquid chromatograph comprising:
a differential refractometer;
a sample introduction section for introducing a sample into a sample introduction channel of the differential refractometer;
an analytical column for separating a sample into components, provided on the sample introduction channel, on an upstream side of the differential refractometer; and
an arithmetic processing section for determining concentration of a component based on a detection signal obtained by the differential refractometer,
wherein the differential refractometer comprising:
a measurement cell including a sample cell through which a sample solution is to pass, and a reference cell for a reference solution;
a sample introduction channel, connected to the sample cell, for introducing a sample into the sample cell together with a mobile phase;
a measurement section including a light source for radiating light toward the measurement cell, and a photodetector for detecting light which has passed through the sample cell and the reference cell;
a mobile phase supply section, including a mobile phase container for containing a mobile phase, for supplying the mobile phase to the sample cell through the sample introduction channel;
a degassing device for degassing the mobile phase inside the mobile phase container; and
a control section for capturing a detection signal obtained by the photodetector from the measurement section, and for controlling operation of the degassing device based on the detection signal, and
wherein the control section includes drift amount setting means for setting a target range of an amount of drift in a baseline of the detection signal of the photodetector, drift amount calculation means for calculating the amount of drift in the baseline of the detection signal before measurement of a sample is performed, and degassing degree control means for adjusting a degree of degassing of the mobile phase by the degassing device before measurement of the sample is performed, in such a way that the amount of drift calculated by the drift amount calculation means falls within the target range set by the drift amount setting means.

9. The liquid chromatograph accor

Assignees

• Shimadzu Corp

Inventors

• Jingu Kumiko
• Fujiwara Masanori
• Tomita Masami
• Kono Yutaka

Classifications

• G01N2021/4146

  Differential cell arrangements · CPC title

• G01N21/4133 Primary

  Refractometers, e.g. differential · CPC title

• G01N30/74

  Optical detectors {(measurement of intensity, velocity, spectral content, polarisation, or phase of infrared, visible or ultraviolet light G01J)} · CPC title