Liquid chromatograph and column oven for use therein
A liquid leakage decision unit includes a leak sensor value storage part that stores a leak sensor value that is based on the intensity of a signal received from a gas sensor; a difference calculation part that, when the signal is received from the gas sensor, calculates, as a difference value, a value obtained by subtracting a previous leak sensor value stored in the leak sensor value storage part from a current leak sensor value; and a liquid leakage detection part that compares the difference value calculated by the difference calculation part with a preset threshold, thereby to detect liquid leakage in the column oven.
1. A column oven for adjusting a temperature of a separation column of a liquid chromatograph, the column oven comprising:
a gas sensor configured to detect vaporized gas of a solvent contained in a mobile phase, which outputs a signal having an intensity dependent on a value detected; and
a liquid leakage decision unit configured to receive the signal output from the gas sensor at regular time intervals to determine whether liquid leakage of the solvent is present or not, the liquid leakage decision unit comprising,
a leak sensor value storage part configured to store a leak sensor value that is based on the intensity of the signal received from the gas sensor,
a difference calculation part configured to, when the signal is received from the gas sensor, identify the leak sensor value that is based on the intensity of the signal as a current leak sensor value, identify a leak sensor value that is based on an intensity of a signal previously received from the gas sensor as a previous leak sensor value, and calculate, as a difference value, a value obtained by subtracting the previous leak sensor value stored in the leak sensor value storage part from the current leak sensor value, and
a liquid leakage detection part configured to detect liquid leakage in the column oven by comparing the difference value calculated by the difference calculation part with a preset threshold,
wherein the threshold is set to a value greater than an amount of change of the leak sensor value due to a temporal change in a sensitivity of the gas sensor.
2. A liquid chromatograph comprising:
a separation column;
a liquid feeder for feeding a mobile phase to an analysis channel having the separation column;
a sample injector for injecting a sample into the analysis channel between the liquid feeder and the separation column; and
a detector for detecting a sample component dissolved out of the separation column, wherein
the liquid chromatograph uses the column oven according to claim 1 as a column oven for adjusting a temperature of the separation column.
3. A column oven for adjusting a temperature of a separation column of a liquid chromatograph, the column oven comprising:
a gas sensor configured to detect vaporized gas of a solvent contained in a mobile phase, which outputs a signal having an intensity dependent on a value detected;
a liquid leakage decision unit configured to receive the signal output from the gas sensor at regular time intervals to determine whether liquid leakage of the solvent is present or not, the liquid leakage decision unit comprising,
a leak sensor value storage part configured to store a leak sensor value that is based on the intensity of the signal received from the gas sensor,
a difference calculation part configured to, when the signal is received from the gas sensor, identify the leak sensor value that is based on the intensity of the signal as a current leak sensor value, identify a leak sensor value that is based on an intensity of a signal previously received from the gas sensor as a previous leak sensor value, and calculate, as a difference value, a value obtained by subtracting the previous leak sensor value stored in the leak sensor value storage part from the current leak sensor value, and
a liquid leakage detection part configured to detect liquid leakage in the column oven by comparing the difference value calculated by the difference calculation part with a preset threshold,
a calibration factor holding part configured to retain a calibration factor that represents a difference in sensitivity between different solvents in association with the gas sensor; and
a sensor output calibration part configured to calibrate the signal received from the gas sensor by using the calibration factor retained in the calibration factor holding part, thereby to obtain the leak sensor value.
4. The column oven according to claim 3 , wherein
the calibration factor holding part is configured to retain a second calibration factor determined so that the leak sensor value remains constant when a vaporized gas concentration of a particular solvent in the column oven is a predetermined concentration, and
the sensor output calibration part is configured to calibrate the signal received from the gas sensor using also the second calibration factor to obtain the leak sensor value.
5. The column oven according to claim 4 , further comprising:
a temperature characteristic holding part configured to retain a temperature characteristic of the sensitivity of the gas sensor,
wherein
the sensor output calibration part is configured to calibrate the signal received from the gas sensor based also on the temperature characteristic retained in the temperature characteristic holding part to obtain the leak sensor value.
6. The column oven according to claim 5 , further comprising:
a humidity characteristic holding part configured to retain a humidity characteristic of the sensitivity of the gas sensor,
wherein
the sensor output calibration part is configured to calibrate the signal received from the gas sensor based also on the humidity characteristic retained in the humidity characteristic holding part to obtain the leak sensor value.
7. The column oven according to claim 4 , further comprising:
a humidity characteristic holding part configured to retain a humidity characteristic of the sensitivity of the gas sensor,
wherein
the sensor output calibration part is configured to calibrate the signal received from the gas sensor based also on the humidity characteristic retained in the humidity characteristic holding part to obtain the leak sensor value.
8. The column oven according to claim 3 , further comprising:
a temperature characteristic holding part configured to retain a temperature characteristic of the sensitivity of the gas sensor,
wherein
the sensor output calibration part is configured to calibrate the signal received from the gas sensor based also on the temperature characteristic retained in the temperature characteristic holding part to obtain the leak sensor value.
9. The column oven according to claim 8 , further comprising:
a humidity characteristic holding part configured to retain a humidity characteristic of the sensitivity of the gas sensor,
wherein
the sensor output calibration part is configured to calibrate the signal received from the gas sensor based also on the humidity characteristic retained in the humidity characteristic holding part to obtain the leak sensor value.
10. The column oven according to claim 3 , further comprising:
a humidity characteristic holding part configured to retain a humidity characteristic of the sensitivity of the gas sensor,
wherein
the sensor output calibration part is configured to calibrate the signal received from the gas sensor based also on the humidity characteristic retained in the humidity characteristic holding part to obtain the leak sensor value.
11. A liquid chromatograph comprising:
a separation column;
a liquid feeder for feeding a mobile phase to an analysis channel having the separation column;
a sample injector for injecting a sample into the analysis channel between the liquid feeder and the separation column; and
a detector for detecting a sample component dissolved out of the separation column, wherein
the liquid chromatograph uses the column oven according to claim 3 as a column oven for adjusting a temperature of the separation column.