JP7312694B2 - Analysis system and analysis method - Google Patents

Description

TECHNICAL FIELD The present invention relates to analysis systems and methods, and more particularly to analysis of samples based on evolved gas analysis.

Various analysis systems have been put into practical use as analysis systems based on evolved gas analysis (EGA). These are described below.

A first analysis system is composed of a pyrolyzer and a mass spectrometer. The temperature of the sample is varied over a predetermined temperature range in the pyrolyzer and a series of gases produced in the process are mass analyzed in the mass spectrometer. A chromatogram is generated from the mass spectrometry results. The horizontal axis is the temperature axis, and the vertical axis is the intensity of the total ion current.

A second analysis system is composed of a pyrolyzer, a column, and a mass spectrometer. In the pyrolyzer, the sample is instantaneously heated to a given temperature, and the gases produced thereby are temporally separated in the column. A plurality of gas components sequentially discharged from the column are subjected to mass analysis in the mass spectrometer. A chromatogram is generated from the mass spectrometry results. The horizontal axis of the chromatogram is the retention time axis, and the vertical axis is the intensity of the total ion current.

A third analysis system is composed of a pyrolyzer, a modulator, a column, and a mass spectrometer (see Patent Document 1). The temperature of the sample is varied over a predetermined temperature range in the pyrolyzer and the resulting gaseous components are accumulated in the modulator. After that, multiple gas components accumulated in the modulator are discharged at once toward the column. Mass spectrometry is performed on multiple gas components temporally separated in the column. This produces a chromatogram. The horizontal axis is the retention time axis, and the vertical axis is the intensity of the total ion current.

There is also known an analysis system comprising a gas chromatogram provided with a primary column and a secondary column and a mass spectrometer connected to the subsequent stage (see Patent Document 2). The primary column separates gas components over a long period of time, and the secondary column separates gas components over a short period of time. Between the primary and secondary columns, a cyclically operated modulator is provided. A two-dimensional chromatogram is generated in the mass spectrometer. The horizontal axis is the retention time of the primary column, and the vertical axis is the retention time of the secondary column.

JP-A-5-157742 JP 2011-122822 A

The first analysis system analyzes a series of gases generated in the process while varying the temperature of the sample, but cannot identify the multiple gas components that make up the series of gases. The second analysis system and the third analysis system are capable of identifying a plurality of gas components forming a gas generated at a predetermined temperature or within a predetermined temperature range, but cannot identify changes in gas components that accompany changes in sample temperature.

An object of the present disclosure is to provide an analysis system and an analysis method that can identify changes in gas components that accompany temperature changes in a sample.

The analysis system according to the present disclosure includes a pyrolysis device that changes the temperature of a sample and discharges a series of gases released from the sample in the process as a gas flow, a modulator that generates a plurality of gas pulses by repeating the accumulation and discharge of the gas flow at a constant cycle, a column that generates a plurality of gas component flows by separating the components of each gas pulse, a measurement unit that measures the plurality of gas component flows, and a thermal analysis image that shows changes in gas components that occur with the temperature change of the sample based on the output of the measurement unit. and an image generator that generates the image.

An analysis method according to the present disclosure includes the steps of: dividing a chromatogram obtained by repeatedly applying component separation to a gas stream generated by temperature change of a sample into a plurality of segments; and mapping the plurality of segments against a space having a temperature axis and a component separation axis to generate a thermal analysis image representing gas component changes that occur with temperature changes of the sample.

According to the present disclosure, it is possible to identify changes in gas components that accompany changes in sample temperature.

It is a figure which shows the analysis system which concerns on embodiment. It is a figure which shows the analysis method which concerns on embodiment. It is a figure which shows the chromatogram produced|generated without operating a modulator, and the chromatogram produced|generated by operating a modulator. It is a figure which shows an example of a thermal-analysis image.

Hereinafter, embodiments will be described based on the drawings.

(1) Outline of Embodiment An analysis system according to an embodiment includes a pyrolyzer, a modulator, a column, a measuring section, and an image generating section. The pyrolyzer changes the temperature of the sample and discharges a series of gases released from the sample in the process as a gas stream. The modulator generates multiple gas pulses by periodically accumulating and expelling gas flow. The column produces multiple gas component streams with component separation for each gas pulse. The measurement unit measures a plurality of gas component flows. The image generator generates a thermal analysis image representing changes in gas components caused by temperature changes of the sample, based on the output of the measurement unit.

Gas flow is generated by changing the temperature of the sample. A gas stream is typically composed of multiple gas components at each instant. By intermittently generating a plurality of gas pulses from a gas stream with a modulator and passing each gas pulse through a column, it is possible to temporally separate the plurality of gas components that make up each gas pulse. Each separated gas component is measured by the measurement unit. A thermal analysis image is generated based on the output of the measurement unit. By observing or analyzing the thermal analysis image, it is possible to identify multiple gas components produced at each temperature of the sample. In other words, it becomes possible to identify changes in gas components that occur with changes in the temperature of the sample.

In the pyrolyzer, the temperature of the sample may be gradually raised or the temperature of the sample may be gradually lowered. Although it is desirable that the temperature of the sample is changed continuously, the temperature of the sample may be changed stepwise. As a modulator, one using hot gas injection and cold gas injection may be employed, or one having an electromagnetic valve may be employed. Although it is desirable to use a column that separates gaseous components by polarity, other types of columns may be used. The measuring unit may be composed of a mass spectrometer, or may be composed of another measuring device such as an FID detector.

In an embodiment, the image generation section has a division section and a mapping section. The dividing section divides the output of the measuring section into a plurality of segments according to a constant cycle. A mapping unit generates a thermal analysis image by mapping the segments to a space having a temperature axis and a retention time axis. The divider operates synchronously with the modulator. However, the delay time is taken into consideration when dividing into a plurality of segments. If each segment includes a margin that does not have a significant signal component, each segment may be mapped after the margin is clipped. A mapping space is, for example, a two-dimensional space having a temperature axis and a retention time axis. The mapping space may be a three-dimensional space having a temperature axis, a retention time axis and an intensity axis.

In embodiments, the measurement unit is a mass spectrometer that mass analyzes a plurality of gas component streams. Based on this assumption, a mass spectrum generator is provided for generating a mass spectrum train based on the output of the mass spectrometer, and a chromatogram generator is provided for generating a chromatogram from the mass spectrum train. A divider divides the chromatogram into segments. According to this configuration, it is possible to observe the mass spectrum of a specific gas component and analyze its composition as necessary. In an embodiment, there are provided means for specifying coordinates or a coordinate range on the thermal analysis image, and means for displaying the mass spectrum corresponding to the specified coordinates or coordinate range based on the mass spectrum sequence.

In the thermal analysis image according to the embodiment, individual intensities forming each segment are represented by at least one of luminance and hue of pixels. Individual intensities may be represented by other information.

An analysis method according to an embodiment includes a dividing step and a generating step. In the splitting step, the chromatogram obtained by repeatedly applying component separation to the gas stream generated by the temperature change of the sample is split into a plurality of segments. In the generating step, by mapping a plurality of segments to a space having a temperature axis and a component separation axis, a thermal analysis image is generated that represents changes in gas components that occur with changes in sample temperature.

The analysis methods described above can be implemented as hardware functions or as software functions. In the latter case, a program for implementing the analysis method described above is installed in the information processing apparatus via a network or via a portable storage medium. The concept of information processing equipment includes computers, mass spectrometers, analytical systems, and the like.

(2) Details of Embodiment FIG. 1 shows an analysis system according to an embodiment. This analysis system is a system for analyzing samples based on evolved gas analysis (EGA), and comprises a pyrolyzer 10, a gas chromatograph 12, a mass spectrometer 14, an information processor 16, and a modulator .

The pyrolysis apparatus 10 changes the temperature of a sample to generate gas, and has a pyrolysis furnace 20 . A sample 24 is placed inside it. A carrier gas 22 is introduced into the pyrolyzer 10 . The temperature of the sample is changed, for example, from several tens of degrees Celsius to several hundred degrees Celsius. A temperature-lowering method may be employed in addition to the temperature-increasing method. A temperature change rate is, for example, 10° C./min. The carrier gas flow rate is, for example, 1.0 ml/min. Any numerical values given in this specification are only examples. The operation of the pyrolysis device 10 is controlled by a control section 18 forming part of the information processing device 16 . In pyrolyzer 10, a series of gases are generated from the sample, which are discharged as a gas stream.

The gas chromatograph 12 has an oven 26 in which a modulator 28 and a column 32 are provided. The internal temperature of the oven 26 is, for example, 300.degree. Modulator 28 is a device that generates a gas pulse train from a gas stream. Modulator 28 repeats gas accumulation and gas release operations. A gas pulse train is thereby generated. A gas pulse train is composed of a plurality of intermittently generated gas pulses.

In this embodiment, low-temperature gas is blown to predetermined locations in the gas tube. This traps the gas generated over a period of time in the gas tube. After that, hot gas is blown to a predetermined location. This releases or releases the accumulated gas. The gas pulse generation period is, for example, 4 seconds or 6 seconds. The hot gas injection period or gas release period is, for example, 0.4 seconds. The gas pulse generation period is defined so that overtaking does not occur in column 32 .

The low temperature gas is, for example, nitrogen gas at -100°C, and the high temperature gas is, for example, nitrogen gas at 350°C. Modulators that repeatedly perform gas accumulation and gas evacuation using solenoid valves may also be used. The modulator 28 is controlled by the controller 18 . A pulse signal 30 is output from the controller 18 to the modulator 28 to define the timing of the gas accumulation operation and the gas discharge operation.

A gas pulse train is delivered to column 32 . Column 32 is a column that separates gas components according to their polarities. Other columns may be used. Its length is for example 2 m and column 32 is a high speed separation column. In column 32, gas components contained in one gas pulse are temporally separated. One gas component stream is produced per gas pulse, ie for each sample temperature.

The mass spectrometer 14 has an ion source 34 , a mass analyzer 36 and a detector 38 . As the ion source 34, ion sources according to various ionization methods can be used. For example, an ion source that complies with the EI ionization method may be used. An ion source that follows the soft ionization method may be used. In the ion source 34, each gas component sent from the column 32 is ionized to produce ions.

In the mass spectrometer 36, each ion is mass-analyzed based on the mass-to-charge ratio (m/z) of each ion. The mass spectrometer 36 is, for example, a time-of-flight mass spectrometer. Other mass spectrometers, such as quadrupole mass spectrometers, may be utilized. The detector 38 has a detector that detects ions. A detection signal is output by detecting ions. For example, mass spectrometry is performed over the range m/z: 50-500. The detection signal is sent to the information processing device 16 . In FIG. 1, illustration of an electric circuit for processing the detection signal is omitted. The electric circuit has an A/D converter and the like.

The information processing device 16 is configured by a computer. The information processing device 16 specifically includes a control section 18 , a mass spectrum generation section 40 , a chromatogram generation section 42 , a thermal analysis image generation section 44 and a display processing section 46 . In practice, they are implemented as multiple functions performed by a processor. The processor is composed of a CPU that executes programs.

The information processing device 16 has a display unit 48, a storage unit 50, and an input unit 52 in addition to the processor. The display unit 48 is configured by, for example, an LCD. The storage unit 50 is configured by a semiconductor memory or a hard disk. The input unit 52 is composed of a keyboard, a pointing device, and the like.

A mass spectrum generator 40 repeatedly generates a mass spectrum based on the detection signal. The generated mass spectrum train is sent to the chromatogram generator 42 . The chromatogram generator 42 generates a TIC chromatogram based on the mass spectrum sequence, specifically by calculating a total ion current (TIC) from each mass spectrum.

The thermal analysis image generator 44 has a dividing section and a mapping section. A divider divides the TIC chromatogram into a plurality of segments. A mapping unit maps the plurality of segments into a predetermined space to generate a thermal decomposition image. The given space is a two-dimensional space defined by a temperature axis and a retention time (polar axis). In mapping, signal strength is associated with hue. The display processing unit 46 has a color calculation function, an image synthesis function, and the like.

A thermal analysis image is displayed on the display unit 48 . A chromatogram or a plurality of segments may be displayed as waveforms on the display unit 48 . Also, a mass spectrum corresponding to specific coordinates in the thermal analysis image may be displayed on the display section 48 . An integrated mass spectrum corresponding to a specific coordinate range in the thermal analysis image may be displayed on the display section 48 .

The storage unit 50 stores mass spectrum sequences, TIC chromatograms, multiple segments, thermal analysis images, and the like. Using the input unit 52, the user designates the temperature change range, modulation period, color conversion mode, and the like. In addition, the input unit 52 is used by the user to specify the coordinates or coordinate range in the thermal analysis image.

Some functions of the information processing device 16 may be executed by another information processing device. Information processor 16 may be incorporated into mass spectrometer 14 . The control unit 18 and the data processing unit (mass spectrum generation unit 40, chromatogram generation unit 42, thermal analysis image generation unit 44, etc.) may be configured by separate information processing devices.

FIG. 2 shows the operation of the analysis system shown in FIG. 1, that is, the analysis method according to the embodiment. Characteristic 53 indicates the change in sample temperature. In characteristic 53, the horizontal axis is the time axis and the vertical axis is the temperature axis. In the illustrated example, the temperature of the sample is increased from T1 to T2. T1 is for example 50°C and T2 is for example 650°C. A series of gases are produced as the sample heats up. Thus, a gas flow is created. At each time the composition of the gas stream is different.

A modulator generates a gas pulse train 54 from the gas stream. The modulator alternately and repeatedly performs an accumulation operation and an opening operation. The gas pulse train 54 is composed of a plurality of intermittently generated gas pulses 58 . Reference numeral 56 indicates an accumulation period. In FIG. 2, the gas pulse train 54 included in the portion of period d is shown in an enlarged manner. The pulse period is 4 seconds or 6 seconds as above. Other periods may be employed.

Each gas pulse is delivered to the column. In the column, the gas components that make up each gas pulse develop on the time axis according to their polarities. This produces multiple gas component streams 60 derived from multiple gas pulses. The left end of each gas component stream 62 is composed of the gas component that reaches the column end earliest, and the right end of each gas component stream 62 is composed of the component that reaches the column end latest.

A chromatogram (TIC chromatogram) is generated by injecting multiple gas component streams 60 into the mass spectrometer. A segment train 64 is generated by dividing the chromatogram by the modulation period. Delay times are taken into account. By dividing the chromatogram, a plurality of segments 66 intermittently arranged on the time axis are generated. Multiple segments 66 correspond to multiple gas component streams 62 . Each segment 66 is a signal or data indicative of a series of gas constituents that make up the gas produced at each temperature.

A thermal analysis image 70 is generated by mapping a plurality of segments 66 in a predetermined space while rotating each of them by 90 degrees (see reference numeral 68). In doing so, each intensity value (each pixel value) that constitutes an individual segment 66 is converted to a hue (see numeral 72).

The upper part of FIG. 3 shows the TIC chromatograph 74 acquired when no modulation is performed. The TIC chromatograph 74 is relatively smooth because no component separation has taken place. The horizontal axis is the time axis, which is also the temperature axis. The vertical axis is the intensity axis.

The lower part of FIG. 3 shows a TIC chromatograph 75 obtained when modulation is performed. The horizontal axis is the time axis, which can also be said to be the temperature axis that changes stepwise. W indicates the period defining the segment 66 . It can be considered that the temperature is constant within the segment 66 . Within each segment 66 are peaks A1-A4, peaks B1-B4, peaks C1-C4, and peaks D1-D4. That is, each gas component can be specifically identified as a waveform by performing modulation.

When each period W includes a margin period W2 having no significant signal, the effective period W1 other than the margin period W2 may be mapped. That is, margins in each segment may be clipped.

FIG. 4 shows an example of a thermal analysis image generated by the analysis method according to the embodiment. It shows, for example, the analysis results of woodworking bonds (vinyl acetate-based bonds). The horizontal axis indicates temperature, which specifically ranges from 50°C to 650°C. The vertical axis is the retention time axis, which indicates the magnitude of polarity. The vertical axis is also the time axis, which corresponds to the modulation period. Reference numeral 78 indicates one segment. A color bar 80 indicates the relationship between intensity and hue. A hue that continuously changes according to the magnitude of intensity is assigned.

The illustrated thermal analysis image 76 includes three regions A, B, and C; For example, topical b1 corresponds to acetic acid, topical b2 corresponds to naphthalene, and topical b3 corresponds to biphenyl. Local c1 corresponds to 1,5-decadiyne. The thermal analysis image 76 makes it possible to identify changes in gas components that occur with temperature changes in the sample. A thermal analysis image 76 or segment set may be analyzed automatically.

In embodiments, specifying a particular coordinate 82 within the thermal analysis image 76 causes the corresponding mass spectrum to be displayed. It is possible to specify the composition of specific gas components in detail by observation of the mass spectrum. When a specific coordinate range 84 is specified in the thermal analysis image 76, the corresponding integrated mass spectrum is displayed. A conventional thermochromatogram can be generated by projecting the thermal analysis image 76 onto the time axis. A portion of the thermal analysis image 76 may be projected onto the retention time axis.

Changing the modulation period changes the content of the thermal analysis image 76 . A plurality of thermal analysis images 76 may be generated while varying the modulation period and evaluated comprehensively.

10 pyrolyzer, 12 gas chromatograph, 14 mass spectrometer, 16 information processor, 28 modulator, 32 column, 40 mass spectrum generator, 42 chromatogram generator, 44 thermal analysis image generator.

Claims (6)

a pyrolysis device that changes the temperature of a sample and discharges as a gas stream a series of gases released from the sample in the process;
a modulator that generates a plurality of gas pulses by repeating accumulation and discharge of the gas flow at regular intervals;
a column for generating a plurality of gas component streams by component separation for each gas pulse;
a measurement unit that measures the plurality of gas component flows;
means for generating a chromatogram based on the output of the measuring unit;
a dividing unit that divides the chromatogram into a plurality of segments according to the constant period;
a mapping unit that maps the plurality of segments to a space having a temperature axis and a retention time axis to generate a thermal analysis image representing changes in gas components caused by changes in the temperature of the sample;
An analysis system comprising: In the analysis system according to claim 1 ,
The measurement unit is a mass spectrometer that mass analyzes the plurality of gas component flows,
A mass spectrum generator that generates a mass spectrum train based on the output of the mass spectrometer, and a chromatogram generator that generates the chromatogram from the mass spectrum train ,
An analysis system characterized by: In the analysis system according to claim 1 ,
Individual intensities that make up each segment in the thermal analysis image are represented by at least one of luminance and hue of pixels;
An analysis system characterized by: In the analysis system according to claim 2 ,
means for specifying coordinates or coordinate ranges on the thermal analysis image;
means for displaying a mass spectrum corresponding to the specified coordinates or coordinate range based on the mass spectrum sequence;
An analysis system comprising: a first step of varying the temperature of the sample and generating a plurality of gas pulses by periodically repeating a series of accumulations and evacuations of gas released from the sample in the process;
a second step of generating a plurality of gas component streams by component separation for each gas pulse;
a third step of measuring the plurality of gas component streams;
a fourth step of generating a chromatogram based on the measurements of the plurality of gas component streams;
a fifth step of dividing the chromatogram into a plurality of segments according to the constant period ;
a sixth step of mapping the plurality of segments against a space having a temperature axis and a component separation axis to generate a thermal analysis image representing changes in gas composition that occur with changes in temperature of the sample;
A method of analysis characterized by comprising A program for executing the fifth step and the sixth step in the analysis method according to claim 5 in an information processing device .

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