US-20260128268-A1 - TIME-OF-FLIGHT MASS SPECTROMETER

US20260128268A1US 20260128268 A1US20260128268 A1US 20260128268A1US-20260128268-A1

Abstract

A TOFMS includes an ion ejection unit, a flight tube, a vacuum chamber in which the flight tube is enclosed, a temperature control unit that controls the temperature of the flight tube, a temperature control section that controls a temperature control operation by the temperature control unit based on an indirectly or directly measured temperature of the flight tube and a target temperature; a temperature sensor that measures an ambient temperature, which is a temperature outside the vacuum chamber; a prediction unit that predicts, based on the ambient temperature and the target temperature, a possibility that the temperature of the flight tube will not reach the target temperature or will not fall within a predetermined allowable temperature range including the target temperature even with the temperature control using the temperature control unit; and a notification unit that performs a notification to a user according to a prediction result.

Inventors

Tomoya Kudo

Assignees

SHIMADZU CORPORATION

Dates

Publication Date: 20260507
Application Date: 20251021
Priority Date: 20241105

Claims (7)

1 . A time-of-flight mass spectrometer comprising: an ion ejection unit; a flight tube that forms a space in which ions ejected from the ion ejection unit fly; a vacuum chamber in which the flight tube is enclosed; a temperature control unit that controls a temperature of the flight tube; and a temperature control section that controls a temperature control operation by the temperature control unit based on an indirectly or directly measured temperature of the flight tube and a target temperature, the time-of-flight mass spectrometer further comprising: a temperature sensor that measures an ambient temperature, which is a temperature outside the vacuum chamber; a prediction unit that predicts, based on the ambient temperature and the target temperature, a possibility that the temperature of the flight tube will not reach the target temperature or will not fall within a predetermined allowable temperature range including the target temperature even with the temperature control using the temperature control unit; and a notification unit that performs a notification to a user according to a prediction result by the prediction unit.
2 . The time-of-flight mass spectrometer according to claim 1 , further comprising: a target temperature setting unit that changes the target temperature according to the prediction result by the prediction unit.
3 . The time-of-flight mass spectrometer according to claim 1 , wherein the prediction unit predicts the possibility that the temperature of the flight tube will not reach the target temperature or will not fall within the predetermined allowable temperature range before execution of temperature control by the temperature control unit or immediately after a start of temperature control.
4 . The time-of-flight mass spectrometer according to claim 1 , wherein the prediction unit predicts the possibility that the temperature of the flight tube will not reach the target temperature or will not fall within the predetermined allowable temperature range by comparing a difference between the ambient temperature and the target temperature with a predetermined determination reference value.
5 . The time-of-flight mass spectrometer according to claim 1 , wherein the prediction unit predicts the possibility that the temperature of the flight tube will not reach the target temperature or will not fall within the predetermined allowable temperature range, assuming that the temperature control unit operates in a range between a capability that is lower than a maximum capability by a predetermined margin and a capability that is higher than a minimum capability by a predetermined margin.
6 . The time-of-flight mass spectrometer according to claim 1 , further comprising: an in-operation prediction unit that, during execution of temperature control by the temperature control unit after the temperature of the flight tube has reached the target temperature or fallen within the predetermined allowable temperature range, predicts a possibility that the temperature of the flight tube will deviate from the target temperature or from the allowable temperature range, based on the ambient temperature, the target temperature, and the temperature of the flight tube, wherein the notification unit performs a notification to the user according to a prediction result by the in-operation prediction unit.
7 . The time-of-flight mass spectrometer according to claim 6 , wherein the in-operation prediction unit predicts a required time until the temperature of the flight tube deviates from the target temperature or from the allowable temperature range, and the notification unit notifies the user of the predicted required time.

Description

TECHNICAL FIELD The present invention relates to a time-of-flight mass spectrometer (TOFMS). BACKGROUND ART In a TOFMS, generally, an ion ejection unit imparts constant kinetic energy to ions to be analyzed, introduces them into a flight space formed within a flight tube, and causes them to fly through the flight space. Then, the time required for the ions to fly a certain distance is measured, and the mass-to-charge ratio (m/z) of the ions is calculated based on the flight time. Therefore, to achieve high mass accuracy in a TOFMS, it is important to keep the flight distance constant. If the flight tube expands or contracts due to temperature changes, the flight distance changes, leading to a decrease in mass accuracy. Therefore, in the TOFMS described in Patent Literatures 1 and 2, a configuration is adopted in which a temperature control unit including a heater is provided on the outside of a vacuum chamber that encloses the flight tube, and the flight tube is indirectly heated using the temperature control unit so that the directly or indirectly detected flight tube temperature reaches a target temperature (45° C. in the example described in Patent Literature 2). However, since the heating capacity of the heater is limited, if the room temperature is too low, the flight tube may not reach the target temperature. Conversely, if the room temperature is too high, the flight tube temperature may exceed the target temperature. Therefore, in conventional TOFMS, a measure is taken to detect whether the flight tube temperature is within a predetermined allowable temperature range that includes the target temperature, and if the flight tube temperature does not fall within the allowable temperature range even after a predetermined time has elapsed, a temperature control error (timeout error) is displayed to call the user's attention. CITATION LIST Patent Literature [Patent Literature 1] International Publication No. WO 2019/224948 [Patent Literature 2] International Publication No. WO 2019/220497 SUMMARY OF INVENTION Technical Problem Normally, the heat capacity of the vacuum chamber and the flight tube is very large, and the thermal time constant is large. Therefore, it takes a considerable amount of time (for example, several tens of hours) from the start of temperature control of the flight tube until the flight tube temperature reaches the vicinity of the target temperature and stabilizes. Therefore, the predetermined time for determining a timeout error as described above is set to be quite long, and it may be the case that it is not known that the ambient temperature is too low or too high until several tens of hours have passed since the startup of the apparatus. In that case, the user will wait for an unnecessarily long time, which reduces the efficiency of the analysis work. The present invention has been made to solve such problems, and its main object is to provide a TOFMS that can improve the efficiency of analysis work by appropriately controlling the temperature of the flight tube to ensure high mass accuracy and reducing wasted work time related to the temperature control. Solution to Problem One aspect of the present invention is a TOFMS comprising an ion ejection unit, a flight tube that forms a space in which ions ejected from the ion ejection unit fly, a vacuum chamber in which the flight tube is enclosed, a temperature control unit that controls the temperature of the flight tube, and a temperature control section that controls the temperature control operation by the temperature control unit based on an indirectly or directly measured temperature of the flight tube and a target temperature, the TOFMS further comprising: a temperature sensor that measures an ambient temperature, which is a temperature outside the vacuum chamber;a prediction unit that predicts, based on the ambient temperature and the target temperature, a possibility that the temperature of the flight tube will not reach the target temperature or will not fall within a predetermined allowable temperature range including the target temperature even with the temperature control using the temperature control unit; anda notification unit that performs a notification to a user according to a prediction result by the prediction unit. Advantageous Effects of Invention In the TOFMS of the above aspect according to the present invention, for example, in an initial stage of analysis preparation work such as before the start of temperature control of the flight tube, if it is predicted that there is a high possibility that the temperature of the flight tube will not fall within (reach) the allowable temperature range even with the temperature control using the temperature control unit, the notification unit can issue a warning to the user. As described above, according to the present invention, the user can grasp the possibility that the temperature control of the flight tube will not be performed appropriately at the initial stage of th