# US 9,518,961 B2 · Liquid chromatograph and column oven used therefor

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- Number: US 9,518,961 B2
- Document ID: US9518961B2
- Status: Granted
- Kind: B2
- Application number: 14/422,467
- Filed: 2013-07-23
- Published: 2015-07-09
- Granted: 2016-12-13
- Earliest claimed: 2012-08-24
- Assignees: Shimadzu Corporation
- Applicants: Shimadzu Corporation
- Inventors: Kazuya Takahashi; Yosuke Iwata
- Web page: https://patentgrep.com/patent/US9518961B2

## CPC

- G01N 30/16: Injection (G01N30/24 takes precedence)
- G01N 30/30: of temperature
- G01N 30/54: Temperature
- G01N 2030/027: {Liquid chromatography}
- G01N: INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES (measuring or testing apparatus or processes other than immunoassay, involving enzymes or microorganisms C12M, C12Q)

## Abstract

A difference between sensitivities among different solvents is preliminarily set as a device constant, using a calibration factor Ge, in a calibration-factor holding part. On the other hand, the sensitivities of gas sensors are measured for each gas sensor, but this measurement is not performed on all solvents and is performed on only a certain solvent, and a threshold value resulted therefrom is held as a reference threshold value Vtho in a reference-threshold-value holding part. A threshold value Vth for another solvent is determined from the reference threshold value Vtho for the certain solvent and from the calibration factor Ge as the device constant according to Vth=Vtho×Ge.

## Claims

### Claim 1

A column oven for performing temperature control on a separation column in a liquid chromatograph, comprising:
a gas sensor for detecting a vaporized gas of a solvent forming a mobile phase;
a reference-threshold-value holding part for holding, as a reference threshold value Vtho, a threshold value determined from a detected value resulting from measurement by the gas sensor, for a vaporized gas of a certain solvent having a lower concentration than an explosive limit concentration;
a calibration-factor holding part for preliminarily holding, as a device constant, a calibration factor Ge indicating a difference between sensitivities of the gas sensor to different solvents;
a threshold-value calibration part for calculating a threshold value Vth from the reference threshold value Vtho held in the reference-threshold-value holding part and from the calibration factor Ge held in the calibration-factor holding part, according to
Vth=Vtho×Ge,
when a type of a solvent to be used is input; and
a liquid leakage detection part for comparing a detected value from the gas sensor with the threshold value calculated by the threshold-value calibration part to detect a liquid leakage within the column oven, during use of the column oven.

### Claim 2 (depends on 1)

The column oven according to claim 1, further comprising a temperature-characteristic holding part for holding a temperature characteristic of the sensitivity of the gas sensor,
wherein the threshold-value calibration part calculates the threshold value Vth, further based on the temperature characteristic held in the temperature-characteristic holding part.

### Claim 3 (depends on 1)

The column oven according to claim 1, further comprising a humidity-characteristic holding part for holding a humidity characteristic of the sensitivity of the gas sensor,
wherein the threshold-value calibration part calculates the threshold value Vth, further based on the humidity characteristic held in the humidity-characteristic holding part.

### Claim 4 (depends on 1)

The column oven according to claim 1, further comprising a low-ignition-point solvent type holding part for holding a type of a solvent having a low ignition point,
wherein, when the type of the solvent to be used is input and when the input type of the solvent to be used agrees with the type of the solvent held in the low-ignition-point solvent type holding part, a display unit is caused to provide display for urging a user to be careful.

### Claim 5 (depends on 1)

The column oven according to claim 1, wherein
the reference-threshold-value holding part holds reference threshold values in plural stages, as the reference threshold value Vtho, and
an alarm or another output form is differentiated depending on a liquid leakage detected based on a threshold value derived from among the reference threshold values in the plural stages.

### Claim 6 (depends on 1)

A liquid chromatograph comprising:
a liquid supply unit for supplying a mobile phase to an analysis flow path including a separation column;
a sample injecting unit for injecting a sample into the analysis flow path between the liquid supply unit and the separation column; and
a detection unit for detecting a sample ingredient eluted from the separation column,
wherein the column oven according to claim 1 is used as a column oven for performing temperature control on the separation column.