Analytical methods, programs, and liquid chromatography-mass spectrometers

Abstract

To provide a technology for improving the accuracy of compound identification in liquid chromatograph mass spectrometers, including single quadrupole mass spectrometers. [Solution] In the analytical apparatus 100, the sample contains a target compound produced by the derivatization of a short-chain fatty acid or organic acid, which is the target compound in the analyte. The central control unit 5 causes the mass spectrometry unit 2 to measure the m / z intensity of the fragments while performing insource collision-induced dissociation on the sample during a given holding time in the liquid chromatograph, and also to measure the m / z intensity of the fragments on the sample during the same given holding time without performing insource collision-induced dissociation.

Description

Technical Field

[0001] The present invention relates to a liquid chromatography mass spectrometer including a single quadrupole mass spectrometer as a mass spectrometer.

Background Art

[0002] In liquid chromatography mass spectrometers, it has been considered difficult to analyze compounds with high volatility and high hydrophilicity. In this regard, conventionally, techniques for derivatizing such compounds before analysis have been disclosed (see Non-Patent Document 1 and Non-Patent Document 2).

Prior Art Documents

Non-Patent Documents

[0003]

Non-Patent Document 1

Non-Patent Document 2

Summary of the Invention

[0004] One example of a mass spectrometer in a liquid chromatography-mass spectrometer is the so-called "single quadrupole mass spectrometer" (hereinafter sometimes referred to as "single quadrupole MS"). A quadrupole mass spectrometer functions as a mass filter. A single quadrupole MS includes one quadrupole mass spectrometer.

[0005] Another example of the mass spectrometers mentioned above is the so-called "triple quadrupole mass spectrometer" (hereinafter sometimes referred to as "triple quadrupole MS"). A triple quadrupole MS includes two quadrupole mass spectrometers. More specifically, in a triple quadrupole MS, two quadrupole mass spectrometers are connected in series with a collision chamber in between.

[0006] Another example of the above-mentioned mass spectrometers is the so-called "quadrupole-time-of-flight mass spectrometer" (hereinafter sometimes referred to as "Q-TOF"). The Q-TOF is a hybrid analytical instrument that combines a quadrupole-type mass spectrometry unit with a time-of-flight mass separation unit.

[0007] Single quadrupole mass spectrometers have advantages over other types of mass spectrometers, such as being less expensive and easier to handle. On the other hand, single quadrupole mass spectrometers may have inferior capabilities in performing precise mass separation compared to other types of mass spectrometers. As a result, when analyzing derivatized compounds as described in Non-Patent Documents 1 and 2, single quadrupole mass spectrometers may mistakenly identify other compounds as the intended compound.

[0008] This invention was conceived in view of the above circumstances, and its purpose is to provide a technique for improving the accuracy of compound identification in liquid chromatograph mass spectrometers, including single quadrupole mass spectrometers. [Means for solving the problem]

[0009] An analytical method according to certain aspects of the present disclosure is a method for analyzing a sample using a liquid chromatograph mass spectrometer, wherein the liquid chromatograph mass spectrometer includes a liquid chromatograph and a single quadrupole mass spectrometer, and the sample includes a target compound produced by the derivatization of a short-chain fatty acid or organic acid, which is a target compound in the analyte, and comprises the steps of: setting the m / z of the fragment of the target compound; measuring the m / z intensity of the fragment in the single quadrupole mass spectrometer while performing insource collision-induced dissociation on the sample for a given retention time in the liquid chromatograph; and measuring the m / z intensity of the fragment in the single quadrupole mass spectrometer without performing insource collision-induced dissociation on the sample for a given retention time in the liquid chromatograph.

[0010] A liquid chromatograph mass spectrometer according to a certain aspect of the present disclosure is a liquid chromatograph mass spectrometer comprising a liquid chromatograph, a single quadrupole mass spectrometer, a computer, and a memory device, wherein the sample of the liquid chromatograph mass spectrometer includes a target compound produced by the derivatization of a short-chain fatty acid or organic acid, which is a target compound in the analyte, and the computer sets the m / z of the fragment of the target compound, and causes the single quadrupole mass spectrometer to measure the m / z intensity of the fragment while performing insource collision-induced dissociation on the sample for a given retention time in the liquid chromatograph, and causes the single quadrupole mass spectrometer to measure the m / z intensity of the fragment without performing insource collision-induced dissociation on the sample for a given retention time in the liquid chromatograph. [Effects of the Invention]

[0011] In accordance with certain aspects of this disclosure, a technique is provided for improving the accuracy of compound identification in a liquid chromatograph-mass spectrometer, including a single quadrupole mass spectrometer as the mass spectrometer. [Brief explanation of the drawing]

[0012] [Figure 1] This is a schematic diagram of the analytical apparatus 100 according to one embodiment of the present disclosure. [Figure 2] This is a schematic diagram relating to the components arranged within the first intermediate vacuum chamber 212. [Figure 3] This diagram shows an example of the data structure of an analysis database that represents the setting conditions for each analysis target. [Figure 4] This figure shows an example of an ion chromatogram of a derivatized compound for the analysis target, "feces." [Figure 5] This figure shows an example of an ion chromatogram of a derivatized compound fragment for the same target of analysis as in Figure 4. [Figure 6] This figure shows an example of an ion chromatogram of a derivatized compound for the target of analysis, "white wine." [Figure 7] This figure shows an example of an ion chromatogram of a derivatized compound fragment for the same target of analysis as in Figure 6. [Figure 8] This is a flowchart showing an example of the information processed by the analytical device 100. [Modes for carrying out the invention]

[0013] The embodiments of this disclosure will be described in detail below with reference to the drawings. In the drawings, the same or corresponding parts are denoted by the same reference numerals, and their descriptions will not be repeated.

[0014] [Configuration of the analytical instrument] Figure 1 is a schematic diagram of an analytical apparatus 100 according to one embodiment of the present disclosure. The analytical apparatus 100 is an example of a single quadrupole mass spectrometer. The analytical apparatus 100 includes a liquid chromatograph section 1 and a mass spectrometry section 2.

[0015] The liquid chromatography unit 1 includes a mobile phase container 11, a pump 12, an injector 13, and a column 14. In the liquid chromatography unit 1, the pump 12 sucks the mobile phase from the mobile phase container 11 and feeds it to the column 14 at a constant flow rate. The injector 13 injects a fixed amount of sample (analysis target) into the mobile phase at a predetermined timing. The injected sample rides on the flow of the mobile phase and is introduced into the column 14. While passing through the column 14, a plurality of compounds (sample components) contained in the sample are separated and eluted from the outlet of the column 14 with a time shift.

[0016] The mass spectrometry unit 2 functions as a detector of the liquid chromatography unit 1. The mass spectrometry unit 2 has a configuration of a multi-stage differential evacuation system. More specifically, in the mass spectrometry unit 2, a first intermediate vacuum chamber 212 and a second intermediate vacuum chamber 213 with gradually increased vacuum levels are arranged between an ionization chamber 211 at approximately atmospheric pressure and a high-vacuum analysis chamber 214 evacuated by a high-performance vacuum pump (not shown).

[0017] An ionization probe 22 for ESI (Electrospray ionization), which sprays while charging the sample solution, is installed in the ionization chamber 211. The ionization chamber 211 and the next-stage first intermediate vacuum chamber 212 are connected through a small-diameter heated capillary 23. The first intermediate vacuum chamber 212 and the second intermediate vacuum chamber 213 are separated by a skimmer 25 having a small hole at the top. Ion guides 24 and 26 are arranged in the first intermediate vacuum chamber 212 and the second intermediate vacuum chamber 213, respectively. By each of the ion guides 24 and 26, ions are transported to the subsequent stage while being converged. In the analysis chamber 214, a quadrupole mass filter 27 for separating ions according to the mass-to-charge ratio and an ion detector 28 are arranged.

[0018] In the mass spectrometry unit 2, when the eluate eluting from the outlet of the column 14 reaches the ESI ionization probe 22, a sample solution with a charge applied from the tip of the ESI ionization probe 22 is sprayed. The sprayed charged droplets are refined while splitting by electrostatic force, and ions derived from the compounds in the sample are generated in the process. These ions are sent to the first intermediate vacuum chamber 212 through the heating capillary 23, converged by the ion guide 24, and sent to the second intermediate vacuum chamber 213 through the small hole at the top of the skimmer 25. These ions are sent to the analysis chamber 214 by the ion guide 26 and introduced into the space in the longitudinal axis direction of the quadrupole mass filter 27. In the ionization chamber 211, ionization may be performed not only by ESI but also by other atmospheric pressure ionization methods such as APCI (atmospheric pressure chemical ionization method) or APPI (atmospheric pressure photoionization method).

[0019] The optical axis C represents the optical axis of ions in the first intermediate vacuum chamber 212, the second intermediate vacuum chamber 213, and the analysis chamber 214. The four rod electrodes constituting the quadrupole mass filter 27 are arranged around the optical axis C. A predetermined voltage is applied to the four rod electrodes constituting the quadrupole mass filter 27 from the voltage generation unit 29. Only ions having a specific mass-to-charge ratio m / z corresponding to the combination of the voltages applied to the four rod electrodes pass through the quadrupole mass filter 27 and reach the ion detector 28. The ion detector 28 outputs a detection signal corresponding to the amount of the reached ions.

[0020] The analyzer 100 further includes a data processing unit 3, an analysis control unit 4, a central control unit 5, an input unit 6, a display unit 7, a storage device 8, a voltage generation unit 29, and an analog-to-digital converter (ADC) 30.

[0021] The detection signal in the ion detector 28 is converted into digital data by the ADC 30 and input to the data processing unit 3.

[0022] The data processing unit 3 includes, as its functions, a chromatogram creation unit, a peak detection unit, and a peak signal-to-noise ratio (SNR) calculation unit. The chromatogram creation unit creates an ion chromatogram for each voltage applied to the four rod electrodes constituting the quadrupole mass filter 27, that is, for each mass-to-charge ratio (m / z). The peak detection unit detects peaks in the ion chromatogram. The peak SNR calculation unit calculates the signal-to-noise ratio of the detected peaks.

[0023] The voltage generation unit 29 supplies voltage to the ion guide 24, the ion guide 26, and the quadrupole mass filter 27.

[0024] The voltage generation unit 29 further applies voltage to the heating capillary 23 and the skimmer 25. More specifically, the voltage generation unit 29 applies a DC bias voltage to the heating capillary 23, the ion guide 24, and the skimmer 25, as will be described later with reference to Figure 2.

[0025] In the first intermediate vacuum chamber 212, although vacuum evacuation is performed, gas (air) continuously flows in from the ionization chamber 211 through the heated capillary 23. Therefore, the vacuum level in the first intermediate vacuum chamber 212 is low, and a large amount of residual gas is present. When ions introduced into the first intermediate vacuum chamber 212 collide with the residual gas with a certain amount of energy, ion cleavage occurs through an action similar to collision-induced dissociation (CID). This type of ion cleavage in the first intermediate vacuum chamber 212 is also referred to as "in-source CID" in this specification.

[0026] The analysis control unit 4 controls the supply of voltage by the voltage generation unit 29. The analysis control unit 4 also controls the operation of the liquid chromatograph unit 1, such as driving the pump 12 and injecting the sample into the injector 13. The central control unit 5 controls the operation of the entire analysis apparatus 100. The central control unit 5 is connected to an input unit 6, a display unit 7, and a storage device 8. The central control unit 5 accepts information input via the input unit 6 and displays the calculation results of the central control unit 5 on the display unit 7. In one implementation example, the input unit 6 is an input device such as a keyboard and / or mouse, and the display unit 7 is a display device such as a display. The storage device 8 stores programs and / or data nonvolatilically.

[0027] In the analytical apparatus 100, at least a portion of the functions of the data processing unit 3, the analysis control unit 4, and the central control unit 5 may be implemented by using a general-purpose personal computer having one or more processors as hardware resources, and by executing software programs installed on the computer. Alternatively, at least a portion of the functions of the data processing unit 3, the analysis control unit 4, and the central control unit 5 may be implemented by integrated circuits such as FPGAs (field-programmable gate arrays) and / or ASICs (application-specific integrated circuits).

[0028] [DC bias voltage for in-source CID] Figure 2 is a schematic diagram relating to the components arranged within the first intermediate vacuum chamber 212. As shown in Figure 2, the voltage generation unit 29 includes a desolvation tube power supply unit 291, an ion guide power supply unit 292, and a skimmer power supply unit 293.

[0029] For the aforementioned "in-source CID" process, a DC bias voltage is applied to the heated capillary 23, ion guide 24, and skimmer 25 from the desolvation tube power supply unit 291, the ion guide power supply unit 292, and the skimmer power supply unit 293, respectively.

[0030] In Figure 2, the voltage applied to the heating capillary 23 is shown as the first voltage Vc. The voltage applied to the ion guide 24 is shown as the second voltage Vg. The voltage applied to the skimmer 25 is shown as the third voltage Vs.

[0031] In one implementation example, the third voltage Vs is kept constant at 0V (ground potential), and the first voltage Vc and second voltage Vg are adjusted according to the compound assumed to be the target of in-source CID. More specifically, the first voltage Vc is set to 1.0V if the assumed target compound is positive and contains ionizable components, and to -1.0V if the assumed target compound is negative and contains ionizable components. The second voltage Vg is set for each assumed target compound.

[0032] [DC bias voltage setting] The analytical device 100, upon receiving a specified analyte, performs the analysis of that analyte according to the set conditions corresponding to the compounds contained in that analyte. Figure 3 shows an example of the data structure of the analytical database representing the set conditions for each analyte. In one implementation example, the analytical database is stored in the storage device 8.

[0033] The analysis database contains two types of information about the analyte: m / z of the derivatized compound and fragment. The "m / z of the derivatized compound" represents the m / z of the compound produced by derivatization (i.e., the derivatized compound) when considering the derivatization of compounds expected to be included in the analyte. In this embodiment, the compound produced by derivatization constitutes an example of a "target compound." In one example, the compound is derivatized with 3-nitrophenylhydrazine (3-NPH).

[0034] "Fragment" refers to a fragment that is expected to be generated from the aforementioned "derivative compound" in the mass spectrometry of the analytical instrument 100. In the analytical database, "Fragment" represents information about such fragments.

[0035] The analysis database includes three items for "fragment": m / z, first voltage, and second voltage. "m / z" represents the m / z of the fragment. "First voltage" and "second voltage" represent the respective settings for the first and second voltages, as explained with reference to Figure 2. "No in-source CID" represents the settings for the first and second voltages when voltage application for in-source CID of the fragment is not intended. "In-source CID enabled" represents the settings for the first and second voltages when voltage application for in-source CID of the fragment is intended.

[0036] Figure 3 shows the registered information for two types of analytes (feces and white wine).

[0037] In the example shown in Figure 3, for the analyte "feces," valeric acid is selected as an example of a compound included in the analyte, and the m / z of the derivatized compound is registered as "238.1." Additionally, the m / z of the fragment is registered as "154.0." Furthermore, without in-source CID, the second voltage setting is "0.0 (V)." With in-source CID, the second voltage setting is "50.0 (V)." In this example, valeric acid constitutes an example of a short-chain fatty acid or organic acid, which are target compounds in the analyte.

[0038] For the analysis target "white wine," malic acid was selected as an example of a compound contained in the analysis target, and the m / z of the derivatized compound is registered as "403.1." Additionally, the m / z of the fragment is registered as "152.0." Furthermore, without in-source CID, the second voltage setting is "0.0 (V)." With in-source CID, the second voltage setting is "-70.0 (V)." In this example, malic acid constitutes an example of a short-chain fatty acid or organic acid, which are target compounds in the analysis target.

[0039] [Changes in ion chromatogram due to in-source CID] <Example of "feces" to be analyzed> Figure 4 shows an example of an ion chromatogram of a derivatized compound for the analyte "feces." Figure 4 shows the ion chromatogram for "238.10," which corresponds to the m / z of the derivatized compound. In Figure 4, the horizontal axis represents the retention time of column 14 of the liquid chromatograph unit 1, and the vertical axis represents the intensity of the detection signal in the ion detector 28 of the mass spectrometer unit 2.

[0040] In the ion chromatogram in Figure 4, line L11 represents the change in detection intensity at m / z "238.10" with respect to retention time. Peaks PA and PB are identified at line L11. Peak PA is presumed to originate from Isovaleric Acid, and peak PB is presumed to originate from Valeric Acid. However, these peaks may originate from other compounds.

[0041] Figure 5 shows an example of an ion chromatogram of a derivatized compound fragment for the same analyte as in Figure 4. Figure 5 shows the ion chromatogram for "154.00", which corresponds to the m / z of the derivatized compound fragment. In Figure 5, the dashed line L12 represents the result without in-source CID, and the solid line L13 represents the result with in-source CID.

[0042] As shown by line L12, without in-source CID, no peaks are detected at the same retention times as peaks PA and PB in Figure 4.

[0043] On the other hand, as shown by line L13, in the case of in-source CID, peak PC is identified at the same retention time as peak PA in Figure 4, and peak PD is identified at the same retention time as peak PB in Figure 4. By referring to Figures 4 and 5, the user can understand that the fragment produced by the cleavage of the compound corresponding to peak PA with in-source CID is detected as peak PC, and the fragment produced by the cleavage of the compound corresponding to peak PB with in-source CID is detected as peak PD.

[0044] Based on the above, the assumption that peak PA in Figure 4 originates from Isovaleric Acid and peak PB in Figure 4 originates from Valeric Acid is supported.

[0045] <Example of "white wine" as the subject of analysis> Figure 6 shows an example of an ion chromatogram of a derivatized compound for the analyte "white wine". Figure 6 shows the ion chromatogram for "403.10", which corresponds to the m / z of the derivatized compound. In Figure 6, the horizontal axis represents the retention time of column 14 of the liquid chromatograph unit 1, and the vertical axis represents the intensity of the detection signal in the ion detector 28 of the mass spectrometer unit 2.

[0046] In the ion chromatogram in Figure 6, line L21 represents the change in detection intensity at m / z "403.10" with respect to retention time. Peak PX is identified at line L21. Peak PX is presumed to originate from Malic Acid. However, this peak may originate from another compound.

[0047] Figure 7 shows an example of an ion chromatogram of a derivatized compound fragment for the same analyte as in Figure 6. Figure 7 shows the ion chromatogram for "152.00", which corresponds to the m / z of the derivatized compound fragment. In Figure 7, the dashed line L22 represents the result without in-source CID, and the solid line L23 represents the result with in-source CID.

[0048] As shown by line L22, without in-source CID, no peak is detected at the same retention time as peak PX in Figure 6.

[0049] On the other hand, as shown by line L23, in the case of in-source CID, peak PY is identified at the same retention time as peak PX in Figure 6. By referring to Figures 6 and 7, users can understand that the fragment produced by the cleavage of the compound corresponding to peak PX with in-source CID was detected as peak PY.

[0050] Based on the above, the assumption that peak PA in Figure 6 originates from Malic Acid is supported. [Information flow] Figure 8 is a flowchart of an example of information processing performed by the analyzer 100. In one implementation example, the processing shown in Figure 8 is performed by one or more processors in the central control unit 5 executing an analytical application program installed in the analyzer 100. In another implementation example, the processing shown in Figure 8 is started when a specific menu for starting the analysis is selected in the application program.

[0051] In step S10, the analysis device 100 acquires information about the object to be analyzed. In one implementation example, the information about the object to be analyzed is input by the user via the input unit 6.

[0052] In step S12, the analyzer 100 identifies information about the target compound. More specifically, the analyzer 100 reads the m / z values ​​of the "derivative compound" associated with the information about the analyte obtained in step S10 from the analysis database.

[0053] In step S14, the analyzer 100 stores the information (m / z) of the target compound identified in step S12 in the memory of the central control unit 5 as a setting value for the target compound.

[0054] In step S16, the analyzer 100 identifies the fragment information. More specifically, the analyzer 100 reads from the analysis database the m / z value, as well as the first and second voltages for both "without in-source CID" and "with in-source CID" for the "fragment" associated with the information to be analyzed acquired in step S10.

[0055] In step S18, the analyzer 100 stores the information of the fragment identified in step S16 as a setting value for the fragment in the memory of the central control unit 5.

[0056] In step S20, the analyzer 100 starts operation of the liquid chromatograph section 1. This initiates the pumping of the mobile phase by the pump 12, and the sample (analyte) is injected into the column 14 by the injector 13.

[0057] In step S22, the analyzer 100 determines whether or not the timing for measuring the m / z in the mass spectrometry unit 2 has arrived.

[0058] The timing of the first measurement of m / z may be predetermined in the analyzer 100, or it may be determined according to a given operation by the user on the input unit 6.

[0059] The timing of the second and subsequent measurements of m / z may be predetermined in the analyzer 100, or it may be determined according to a given operation by the user on the input unit 6. In one implementation example, the timing of the second and subsequent measurements may be set to occur at regular intervals (for example, every minute) after the arrival of the previous measurement timing.

[0060] The analyzer 100 repeatedly performs the control in step S22 until it determines that the measurement timing has arrived (NO in step S22). Once it determines that the measurement timing has arrived (YES in step S22), it proceeds to step S24.

[0061] In step S24, the analyzer 100 instructs the mass spectrometer 2 to measure the m / z intensity of the target compound.

[0062] In step S26, the analyzer 100 causes the mass spectrometer 2 to measure the m / z intensity of the fragment under conditions without in-source CID. In step S26 and step S28 described later, "m / z of the fragment" refers to the m / z of the fragment identified in step S16.

[0063] In step S28, the analyzer 100 causes the mass spectrometer 2 to measure the m / z intensity of the fragment under conditions with in-source CID.

[0064] In step S30, the analyzer 100 determines whether the conditions for ending the m / z measurement by the mass spectrometer 2 have been met. The conditions for ending the measurement may be set in advance in the analyzer 100, or they may be met by a given operation of the user to the input unit 6. If the analyzer 100 determines that the conditions for ending the m / z measurement have not yet been met (NO in step S30), it returns control to step S22. If it determines that the conditions for ending the m / z measurement have been met (YES in step S30), it proceeds to step S32.

[0065] Through the control in steps S20 to S28, the intensity of three types of m / z (m / z of the target compound, m / z of the fragment under conditions without insource CID, and m / z of the fragment under conditions with insource CID) is measured each time the timing for m / z measurement arrives until the measurement is completed in step S30. In one implementation example, at predetermined time intervals (for example, every minute), the m / z intensity of the target compound is measured for the first fraction of the eluate from column 14, the m / z intensity of the fragment under conditions without insource CID is measured for the second fraction of the eluate from column 14, and the m / z intensity of the fragment under conditions with insource CID is measured for the first fraction of the eluate from column 14.

[0066] In step S32, the analyzer 100 instructs the data processing unit 3 to create ion chromatograms for the target compound (m / z), the fragment (m / z) under conditions without in-source CID, and the fragment (m / z) under conditions with in-source CID. This creates ion chromatograms as described with reference to Figures 4 and 5, or Figures 6 and 7.

[0067] In step S34, the analyzer 100 outputs three types of ion chromatograms created in step S32. The ion chromatograms are examples of the distribution of ion detection intensity over multiple retention periods.

[0068] The output in step S34 may be displayed on the display unit 7 or transmitted to an external device. For transmission, the analyzer 100 may have a communication interface for communicating with an external device.

[0069] Subsequently, the analyzer 100 stops the operation of the liquid chromatograph unit 1, thereby ending the process shown in Figure 8.

[0070] In the process shown in Figure 8 described above, the analyzer 100 outputs ion chromatograms for the target compound at m / z, for the fragment at m / z under conditions without insource CID, and for the fragment at m / z under conditions with insource CID. Based on the fact that a peak of a fragment that did not appear under conditions without insource CID appeared under conditions with insource CID at a certain retention time, the user can improve the accuracy of their assumption that a peak that appears at the same retention time as the target compound at the corresponding m / z is the peak of the target compound.

[0071] In one implementation example, the fact that the retention times are the same means that, in step S22, from c, steps S22 to S28, the m / z intensity of the target compound, the m / z intensity of the fragment under conditions without in-source CID, and the m / z intensity of the fragment under conditions with in-source CID are measured at regular intervals. The three fractions used to measure each of these three types of m / z intensities can be understood as belonging to the eluate at the same measurement timing. The sample contained in the eluate at the same measurement timing can be understood as the sample at one retention time in liquid chromatography. Note that the order in which the above three types of m / z intensities are measured at each measurement timing is not limited to that shown in Figure 8. The above three types of m / z intensities may be measured in any order.

[0072] Furthermore, the peak detection in the ion chromatograms of the target compound (m / z), the fragment (m / z) under conditions without in-source CID, and the fragment (m / z) under conditions with in-source CID may contain different errors. Therefore, even if there are some differences in the retention times at which peaks are detected in the ion chromatograms of the target compound and the fragment, the peak of the fragment can be understood to correspond to the peak of the target compound.

[0073] [Pattern] Those skilled in the art will understand that the above-described exemplary embodiments are specific examples of the following embodiments.

[0074] (Section 1) An analytical method according to one embodiment is a method for analyzing a sample using a liquid chromatograph mass spectrometer, wherein the liquid chromatograph mass spectrometer includes a liquid chromatograph and a single quadrupole mass spectrometer, the sample includes a target compound produced by the derivatization of a short-chain fatty acid or organic acid which is a target compound in the analyte, and the method may include the steps of: setting the m / z of a fragment of the target compound; measuring the m / z intensity of the fragment in the single quadrupole mass spectrometer while performing insource collision-induced dissociation on the sample during a given holding time in the liquid chromatograph; and measuring the m / z intensity of the fragment in the single quadrupole mass spectrometer without performing insource collision-induced dissociation on the sample during a given holding time in the liquid chromatograph.

[0075] According to the analytical method described in paragraph 1, a technique is provided for improving the accuracy of compound identification in a liquid chromatograph mass spectrometer, including a single quadrupole mass spectrometer, as the mass spectrometer.

[0076] (Section 2) The analytical method described in Section 1 further comprises the step of obtaining information that identifies the analyte, and the step of setting the m / z of the fragment of the target compound may include obtaining the m / z of the fragment by referring to information associated with the analyte in a database.

[0077] According to the analytical method described in Section 2, the m / z of the target compound fragment corresponding to the analyte is obtained according to the information registered in the database.

[0078] (3) The analysis method described in paragraph 1 or 2 further comprises the step of obtaining information to identify the object to be analyzed, and the step of measuring the m / z intensity of the fragment while performing the insource collision-induced dissociation may include setting the voltage conditions applied in the insource collision-induced dissociation by referring to information associated with the object to be analyzed in a database.

[0079] According to the analysis method described in Section 3, the voltage conditions for insource collision-induced dissociation of fragments are set according to the information registered in the database.

[0080] (Clause 4) The analytical method described in any one of paragraphs 1 to 3 may further comprise the steps of setting the m / z of the target compound and measuring the m / z intensity of the target compound with respect to the sample during the given holding time in the liquid chromatograph using the single quadrupole mass spectrometer.

[0081] According to the analytical method described in Section 4, the m / z of the target compound is measured during the same retention period as the m / z of the fragment.

[0082] (Clause 5) The analytical method described in paragraph 4 further comprises the step of obtaining information that identifies the analyte, and the step of setting the m / z of the target compound may include obtaining the m / z of the target compound by referring to information associated with the analyte in a database.

[0083] According to the analytical method described in Section 5, once the analyte is obtained, the m / z of the target compound associated with that analyte is set by referencing the database.

[0084] (Clause 6) The analytical method described in paragraph 4 or 5 may further comprise the step of creating an intensity distribution over multiple retention periods for the m / z intensity of the fragment measured while performing insource collision-induced dissociation, the m / z intensity of the fragment measured without performing insource collision-induced dissociation, and the m / z intensity of the target compound.

[0085] According to the analytical method described in Section 6, in addition to the m / z intensity distribution of the target compound, intensity distributions are created for both cases where insource collision-induced dissociation is performed on the fragment of the target compound and where it is not performed.

[0086] (Clause 7) A program according to one embodiment may be executed by a computer, causing the computer to perform the analysis method described in any one of paragraphs 1 to 6.

[0087] According to the program described in Section 7, techniques are provided to improve the accuracy of compound identification in liquid chromatograph mass spectrometers, including single quadrupole mass spectrometers, as mass spectrometers.

[0088] (Clause 8) A liquid chromatograph mass spectrometer according to one embodiment is a liquid chromatograph mass spectrometer comprising a liquid chromatograph, a single quadrupole mass spectrometer, and a computer, wherein the sample of the liquid chromatograph mass spectrometer includes a target compound produced by the derivatization of a short-chain fatty acid or organic acid, which is a target compound in the analyte, and the computer sets the m / z of the fragment of the target compound, and causes the single quadrupole mass spectrometer to measure the m / z intensity of the fragment while performing insource collision-induced dissociation on the sample for a given holding time in the liquid chromatograph, or causes the single quadrupole mass spectrometer to measure the m / z intensity of the fragment without performing insource collision-induced dissociation on the sample for a given holding time in the liquid chromatograph.

[0089] According to the liquid chromatograph mass spectrometer described in paragraph 8, a technique is provided for improving the accuracy of compound identification in a liquid chromatograph mass spectrometer, including a single quadrupole mass spectrometer as the mass spectrometer.

[0090] (Clause 9) In the liquid chromatograph mass spectrometer described in Clause 8, the computer may acquire information identifying the analyte and set the m / z of the fragment of the target compound by referring to information associated with the analyte in a database to acquire the m / z of the fragment.

[0091] According to the liquid chromatograph-mass spectrometer described in Section 9, the m / z values ​​of the target compound fragments corresponding to the analyte are obtained according to the information registered in the database.

[0092] (Clause 10) The liquid chromatograph mass spectrometer described in paragraph 8 or 9 further comprises the step of acquiring information to identify the analyte, and the step of measuring the m / z intensity of the fragment while performing the insource collision-induced dissociation may include setting the voltage conditions applied in the insource collision-induced dissociation by referring to information associated with the analyte in a database.

[0093] According to the liquid chromatograph-mass spectrometer described in Section 10, the voltage conditions for in-source collision-induced dissociation of fragments are set according to information registered in the database.

[0094] (Clause 11) In the liquid chromatograph mass spectrometer according to any one of Clauses 8 to 10, the computer may set the m / z of the target compound and cause the single quadrupole mass spectrometer to measure the m / z intensity of the target compound for the sample during the given holding time in the liquid chromatograph.

[0095] According to the liquid chromatograph-mass spectrometer described in Section 11, the m / z of the target compound is measured during the same retention period as the m / z of the fragment.

[0096] (Clause 12) In the liquid chromatograph mass spectrometer described in paragraph 11, the computer may obtain information identifying the analyte and obtain the m / z of the target compound by referring to information associated with the analyte in a database.

[0097] According to the liquid chromatograph-mass spectrometer described in paragraph 12, once the analyte is acquired, the m / z of the target compound associated with that analyte is set by referring to the database.

[0098] (Clause 13) In the liquid chromatograph mass spectrometer described in paragraph 11 or 12, the computer may output the intensity distributions over multiple retention periods for the m / z intensity of the fragment measured while performing insource collision-induced dissociation, the m / z intensity of the fragment measured without performing insource collision-induced dissociation, and the m / z intensity of the target compound.

[0099] According to the liquid chromatograph-mass spectrometer described in paragraph 13, in addition to the m / z intensity distribution of the target compound, intensity distributions are created for both when insource collision-induced dissociation of the fragment of the target compound is performed and when it is not performed.

[0100] The embodiments disclosed herein should be considered in all respects to be illustrative and not restrictive. The scope of this disclosure is indicated by the claims rather than by the description of the embodiments above, and all modifications within the meaning and scope equivalent to the claims are intended to be included. Furthermore, each technology in the embodiments is intended to be practiced individually or, as far as possible, in combination with other technologies in the embodiments. [Explanation of symbols]

[0101] 1 Liquid chromatograph section, 2 Mass spectrometry section, 3 Data processing section, 4 Analysis control section, 5 Central control section, 6 Input section, 7 Display section, 8 Memory device, 11 Mobile phase container, 12 Pump, 13 Injector, 14 Column, 22 Ionization probe for ESI, 23 Heated capillary, 24, 26 Ion guide, 25 Skimmer, 27 Quadrupole mass filter, 28 Ion detector, 29 Voltage generator, 100 Analytical instrument, 211 Ionization chamber, 212 First intermediate vacuum chamber, 213 Second intermediate vacuum chamber, 214 Analysis chamber.

Claims

1. A method for analyzing a sample using a liquid chromatography-mass spectrometer, The liquid chromatograph mass spectrometer includes a liquid chromatograph and a single quadrupole mass spectrometer. The sample contains a target compound produced by the derivatization of a short-chain fatty acid or organic acid, which is the target compound in the analyte. The steps include setting the m / z of the target compound fragment, In the single quadrupole mass spectrometer, the steps include measuring the m / z intensity of the fragment while performing insource collision-induced dissociation on the sample during a given holding time in the liquid chromatograph, An analytical method comprising the steps of measuring the m / z intensity of the fragments in the single quadrupole mass spectrometer for the sample during a given holding time in the liquid chromatograph without performing in-source collision-induced dissociation.

2. The step further comprises obtaining information to identify the subject of analysis, The analytical method according to claim 1, wherein the step of setting the m / z of the target compound fragment includes obtaining the m / z of the fragment by referring to information associated with the analyte in a database.

3. The step further comprises obtaining information to identify the subject of analysis, The analysis method according to claim 1, wherein the step of measuring the m / z intensity of the fragment while performing the insource collision-induced dissociation includes setting the voltage conditions applied in the insource collision-induced dissociation by referring to information associated with the object to be analyzed in a database.

4. The steps include setting the m / z of the target compound, The analytical method according to claim 1, further comprising the step of measuring the m / z intensity of the target compound with respect to the sample during a given holding time in the liquid chromatograph using the single quadrupole mass spectrometer.

5. The step further comprises obtaining information to identify the subject of analysis, The analytical method according to claim 4, wherein the step of setting the m / z of the target compound includes obtaining the m / z of the target compound by referring to information associated with the object of analysis in a database.

6. The analytical method according to claim 4 or claim 5, further comprising the step of creating an intensity distribution over a plurality of retention periods for the m / z intensity of the fragment measured while performing insource collision-induced dissociation, the m / z intensity of the fragment measured without performing insource collision-induced dissociation, and the m / z intensity of the target compound.

7. A program that, when executed by a computer, causes the computer to perform the analysis method described in claim 1 or claim 2.

8. Liquid chromatography and, Single quadrupole mass spectrometer and A liquid chromatograph mass spectrometer equipped with a computer, The sample of the liquid chromatograph mass spectrometer contains a target compound produced by the derivatization of a short-chain fatty acid or organic acid, which is the target compound in the analyte. The aforementioned computer, The m / z of the fragment of the target compound is set, The single quadrupole mass spectrometer is used to measure the m / z intensity of the fragments while performing insource collision-induced dissociation on the sample during a given holding time in the liquid chromatograph. A liquid chromatograph mass spectrometer that causes the single quadrupole mass spectrometer to measure the m / z intensity of the fragments of the sample during a given holding time in the liquid chromatograph without performing in-source collision-induced dissociation.

9. The computer acquires information to identify the object to be analyzed, The liquid chromatograph mass spectrometer according to claim 8, wherein setting the m / z of the fragment of the target compound includes obtaining the m / z of the fragment by referring to information associated with the analyte in a database.

10. The step further comprises obtaining information to identify the subject of analysis, The liquid chromatograph mass spectrometer according to claim 8, wherein the step of measuring the m / z intensity of the fragment while performing the insource collision-induced dissociation includes setting the voltage conditions applied in the insource collision-induced dissociation by referring to information associated with the object to be analyzed in a database.

11. The aforementioned computer, The m / z of the target compound is set, The liquid chromatograph mass spectrometer according to claim 8, wherein the single quadrupole mass spectrometer is used to measure the m / z intensity of the target compound for the sample during the given holding time period in the liquid chromatograph.

12. The aforementioned computer, Obtain information that identifies the subject of analysis, The liquid chromatograph mass spectrometer according to claim 11, which obtains the m / z of the target compound by referring to information associated with the object to be analyzed in a database.

13. The liquid chromatograph mass spectrometer according to claim 11 or 12, wherein the computer outputs the intensity distribution over multiple retention periods for the m / z intensity of the fragment measured while performing insource collision-induced dissociation, the m / z intensity of the fragment measured without performing insource collision-induced dissociation, and the m / z intensity of the target compound.

Images