JP3204062B2 - Liquid chromatograph mass spectrometer - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a liquid chromatograph mass spectrometer (hereinafter referred to as LC / MS), and more particularly, to a probe for electrospray ionization,
The present invention relates to an LC / MS that can selectively use an atmospheric pressure chemical ionization probe.

[0002]

2. Description of the Related Art In LC / MS, components separated in a liquid chromatograph section are ionized and introduced into a mass spectrometry section. Therefore, an interface for ionizing the separated components is needed. Interfaces generally used for LC / MS include electrospray interface (ESI) and atmospheric pressure chemical ionization interface (A
PCI).

In the ESI method, a liquid sample is sent to the tip of a thin nozzle, and a high voltage is applied to the tip of the nozzle. As a result, a strong non-uniform electric field is formed at the tip of the nozzle, and the liquid sample is sprayed as a charged droplet by the strong electric field. Is performed.

On the other hand, in the APCI method, a liquid sample is forcibly sprayed by a gas flow in a nebulizer (atomizer), and the liquid sample is desolvated by heating the liquid sample. The sample is ionized (chemical ionization). FIG. 3 shows a conventional LC /
It is a figure showing the general composition of MS. Reference numeral 10 denotes a liquid chromatograph unit, and reference numeral 20 denotes a mass spectrometric unit. An interface unit 30 has an electrospray ionization unit 31 using the ESI method. The electrospray ionization unit 31 is fixed by a fixing member 33. The fixing member 33 has a fixed position with respect to the pipe 32 serving as the entrance of the sample to the mass spectrometer 20. In this drawing, a housing shared with the mass spectrometer 20 is used as the fixing member 33. That is, the hole 33a provided in the housing functions as a mounting portion for the electrospray ionization unit 31, and the electrospray ionization unit 31 is inserted into the hole 33a and fixed with a mounting screw (not shown). The positional relationship between the unit 31 and the mass analysis unit 20 is determined. The electrospray probe 31a of the electrospray ionization unit 31 has a thin tube through which the sample liquid sent from the liquid chromatograph unit 10 passes. The tip on the side facing the pipe 32 has a needle shape, and has passed through the thin tube. The liquid is ejected from the nozzle at the tip of the needle. Then, a high voltage of about several KV is applied to the electrospray probe 31a from a high voltage generating circuit (not shown). With this setting, the liquid sample sent from the liquid chromatograph unit 10 is drawn out in a spray form by a strong electric field formed near the nozzle at the tip of the needle, and becomes ions or charged microdroplets.
Enter 2.

The charged microdroplets are heated by a wound heater (not shown) in the pipe 32 to evaporate the solvent, and are further miniaturized and collided with other particles for ionization. The promoted and generated ions are extracted from the pipe 32 and sent into the mass spectrometer 20.

On the other hand, when performing ionization by the APCI method, an atmospheric pressure chemical ionization unit 34 as shown in FIG. 4 is attached to a hole 33a of a housing as a fixing member 33 instead of the electrospray ionization unit 31 of FIG. Can be That is, a probe 34a having a thin tube through which a sample liquid passes and having a needle-like tip, an atomizing chamber 34b provided to surround the needle portion of the probe 34a, and a discharge electrode 34c attached to the front surface of the opening of the atomizing chamber Is attached. The atomization chamber 34b is heated by a heater (not shown), and a voltage of several KV is applied to the discharge electrode 34c. In this manner, the liquid sample sent from the liquid chromatograph unit 10 is separately provided with the probe 34a.
Is sprayed into the atomizing chamber 34b from the nozzle at the tip of the needle of the probe 34a by the atomizing gas from the gas line connected to the nozzle 34, and is contacted with buffer ions generated at the discharge electrode after being desolvated by the heater. Ionized. Then, the generated ions are sent to the mass spectrometry unit 20 via the heated pipe 32 while ionization is promoted in the same manner as in the above-described ESI method.

[0007]

In the conventional LC / MS, one of the electrospray ionization unit 31 and the atmospheric pressure chemical ionization unit 34 is selected according to the sample to be measured, and an appropriate one is attached to the interface unit. Then, the parameter is set again according to the ionization unit, and then the measurement is performed.

The operator replaces the electrospray ionization section with the atmospheric pressure chemical ionization section and thereafter sets parameters such as the set voltage. At this time, the operator determines which ionization section is attached. The judgment was visually determined by the measurer, and there was a risk of an erroneous operation. If an erroneous operation was performed, the ionization part would be damaged, or measurement would be performed under inappropriate setting conditions. SUMMARY OF THE INVENTION The present invention solves the above-described problems, and when replacing an ionization unit, automatically sets a correct setting according to the installed ionization unit, thereby eliminating an erroneous operation.
It is intended to provide S.

[0009]

A liquid chromatograph / mass spectrometer (LC / MS) according to the present invention, which has been made to solve the above problems, has a liquid chromatograph between a liquid chromatograph section and a mass spectrometric section. In a liquid chromatograph mass spectrometer provided with an interface section for ionizing a liquid sample given from the section and supplying the same to a mass analysis section, an electrospray ionization section and an atmospheric pressure chemical ionization section that can be attached to and detached from the interface section, An ionization means mounting section of an interface section to which the electrospray ionization section and the atmospheric pressure chemical ionization section can be interchangeably mounted, and whether the mounted ionization section is an electrospray ionization section or an atmospheric pressure chemical ionization section. According to the identification means and the identification result by the identification means Characterized by comprising an automatic setting unit for the recto b ionization unit or parameter setting of atmospheric pressure chemical ionization unit.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION In the LC / MS of the present invention, the interface section is provided with identification means for identifying whether the attached probe is an electrospray ionization section or an atmospheric pressure chemical ionization section. Which ionization section is attached is identified. And
Settings suitable for the electrospray ionization unit or the atmospheric pressure chemical ionization unit are automatically performed by the automatic setting unit according to the result of the identification unit. Thereby, since the setting according to the ionization unit is performed, the problem due to the erroneous operation is eliminated.

An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a configuration diagram showing a main part of an LC / MS showing one embodiment of the present invention. Note that the same components as in the conventional example are denoted by the same reference numerals as in FIGS.

As shown in the figure, the interface unit 30
The electrospray ionization section 31 is inserted into a hole 33a as a mounting section of a fixing member 33 using a housing. Then, the electrospray ionization unit 31
A pipe 32 as a sample introduction path to the mass spectrometry unit 20 is attached to the vicinity of the tip of the needle of the electrospray probe 31a. This pipe 32
Is provided with a heater (not shown). In addition, as shown in FIG. 2, by replacing the electrospray ionization section 31 with the electrospray ionization section 31, the atmospheric pressure chemical ionization section 34 can be attached to the hole 33a. That is, both the electrospray ionization unit 31 and the atmospheric pressure chemical ionization unit 34 can be attached to and detached from the hole 33a. A microswitch 40 is mounted in the interface unit 30 and the microswitch 4
The zero contact is turned off when the electrospray ionization unit 31 is attached, and turned on when the atmospheric pressure chemical ionization unit 34 is attached. That is, the contact point of the microswitch is pressed when the atmospheric pressure ionization part 34 is inserted into the hole 33a as shown in FIG. 2, while the contact is made when the electrospray ionization part 31 is attached as shown in FIG. Not to be. In this embodiment, the microswitch is switched using the difference in the axial length between the two ionization units.
However, the present invention is not limited to this. For example, one of the ionization units may be provided with a protrusion for pressing a contact, and the switch may be switched by this. In short, the contact may be pressed only when one of the ionization sections is attached. A contact signal of the microswitch 40 is connected so as to be sent to a CPU 41 of a computer for controlling the liquid chromatograph mass spectrometer (shown by A in the figure), and any ionization unit is connected by a signal from the microswitch 41. Is identified. The CPU 41
A high-voltage power supply for applying a high voltage to the electrospray ionization unit 31, a high-voltage power supply for applying a high voltage to the atmospheric pressure chemical ionization unit 34 (may be shared with the electrospray ionization unit), and A heater temperature controller is connected by a cable, and also controls these.

Next, the operation of this embodiment will be described. First, the electrospray unit 31 is attached to the hole 33a. Then, since the contact of the microswitch 40 is not pressed, the CPU 41 determines that the electrospray ionization unit 31 is currently mounted, and sets the voltage to be set to, for example, 4 KV as a set voltage signal from the CPU 41 to the high-voltage power supply. Is sent. The high-voltage power supply receives this signal and sets a parameter to a setting value indicated by the setting signal.

Next, when the ionization section is replaced with the atmospheric pressure chemical ionization section 34, the contact point of the microswitch 40 is pressed, whereby it is determined that the atmospheric pressure chemical ionization section 34 is currently mounted. . And CP
A setting signal for setting, for example, 5 KV is sent as a set voltage signal from U41 to the high voltage power supply, and a setting signal for setting the set temperature to, for example, 400 degrees Celsius is sent to the heater temperature controller. Upon receiving these signals, the high-voltage power supply device and the temperature control device are set to the respective set values.

Since the measurement is started by the measurer after the automatic setting as described above, there is no problem due to erroneous setting when replacing the ionization unit.

[0016]

As described above, as described above, the LC / M according to the present invention is used.
In S, an identification unit for identifying the ionization unit attached to the interface unit is provided, and appropriate parameters are automatically set in response to a signal from the identification unit.
Erroneous setting does not occur. Therefore, it is possible to prevent the ionization unit from being damaged due to an incorrect setting or to perform measurement under an incorrect setting.

[Brief description of the drawings]

FIG. 1 is a configuration diagram when an electrospray ionization unit is attached to an interface unit of a liquid chromatograph mass spectrometer according to one embodiment of the present invention.

FIG. 2 is a configuration diagram when an atmospheric pressure chemical ionization unit is attached to an interface unit of a liquid chromatograph mass spectrometer according to one embodiment of the present invention.

FIG. 3 is a configuration diagram (ESI method) of a conventional liquid chromatograph mass spectrometer.

FIG. 4 is a configuration diagram (APCI method) of a conventional liquid chromatograph mass spectrometer.

[Explanation of symbols]

 10: Liquid chromatograph unit 20: Mass spectrometry unit 30: Interface unit 31: Electrospray ionization unit 33: Fixing member, 33a: Hole (ionization unit attachment unit) 34: Atmospheric pressure chemical ionization unit 40: Microswitch (identification unit) 41: CPU (automatic setting unit)

──────────────────────────────────────────────────続 き Continued on the front page (58) Fields surveyed (Int. Cl. ⁷ , DB name) G01N 27/62-27/70 G01N 30/72 H01J 49/00-49/48

Claims (1)

(57) [Claims] 1. A liquid chromatograph / mass spectrometer having an interface between a liquid chromatograph unit and a mass spectrometer unit for ionizing a liquid sample supplied from the liquid chromatograph unit and supplying the ionized sample to the mass spectrometer unit. An electrospray ionization unit and an atmospheric pressure chemical ionization unit that can be attached to and detached from the interface unit; and an ionization unit attachment unit of an interface unit to which the electrospray ionization unit and the atmospheric pressure chemical ionization unit can be interchangeably attached. Identification means for identifying whether the ionization part is an electrospray ionization part or an atmospheric pressure chemical ionization part, and automatic setting for setting parameters of the electrospray ionization part or the atmospheric pressure chemical ionization part according to the identification result by the identification means That you have a department Characteristic liquid chromatograph mass spectrometer.