JP2017102100A - Evolved gas analysis method and evolved gas analysis device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an evolved gas analysis method and device which can simply correct a machine difference in detection sensitivity and daily variations, etc., and quantitate a measurement object with high accuracy.SOLUTION: Provided is a method for calibrating an evolved gas analysis device equipped with a sample holder, a heating unit for heating a sample and generating a gas component, an ion source for ionizing the gas component and generating ions, a mass spectrometer for analyzing the ions and detecting a gas component, and a gas passage in which a mixed gas of the gas component with a carrier gas for guiding the gas component to the mass spectrometer flows, wherein the method includes: a discharge flow rate adjustment step for adjusting a discharge flow rate of the mixed gas in a branch path to the outside; a sample holder cooling step for bringing the sample holder into contact with a cooling unit and cooling the sample holder; and a correction step for using a standard sample that contains the gas component as a measurement object, to (1) calibrate a spectral position in a mass spectrum, (2) calculate a sensitivity correction coefficient Cs=Ss/S, and (3) calculate a heating correction coefficient H=t/ts for correcting a heating speed of the sample in the heating unit when measuring the gas component of the actual sample.SELECTED DRAWING: Figure 10

Description

  The present invention relates to a generated gas analyzing method and a generated gas analyzing apparatus for ionizing and mass-analyzing a gas component generated by heating a sample and performing identification and quantification of the sample.

In order to ensure the flexibility of the resin, the resin contains plasticizers such as phthalates, but the use of four types of phthalates is beyond 2019 due to the European Specific Hazardous Substances Regulation (RoHS). It was to be restricted. Therefore, it is necessary to identify and quantify the phthalate ester in the resin.
Since the phthalate ester is a volatile component, it can be analyzed by applying a conventionally known evolved gas analysis (EGA). In this generated gas analysis, a gas component generated by heating a sample is analyzed by various analyzers such as a gas chromatograph and a mass spectrometer.

By the way, since mass spectrometry has very high sensitivity and is excellent in detection accuracy, it is necessary to calibrate the sensitivity and the like accurately. In addition, since the mass spectrometer is a general-purpose analytical instrument, the user has to perform sensitivity adjustment and calibration by himself / herself according to the measurement target, requiring complicated work.
Therefore, techniques (Patent Documents 1 and 2) for calibrating the mass-to-charge ratio m / z (mass number) of the measurement object from the mass spectrum of the standard sample are disclosed.

JP 2008-190898 A JP 2005-106524 JP

However, since the quantification of the gas component to be measured is calculated based on the area S of the chromatogram C as shown in FIG. 13, the chromatogram C also needs to be calibrated and adjusted. The area S of the chromatogram C is affected by the deterioration of the ion source that ionizes the gas component, the measurement temperature, and the like. The shape of the chromatogram (time t giving the maximum peak) is affected by the heating rate (heating rate) when the sample is heated, and changes to time t 'when the shape of the chromatogram changes to C'. The area S ′ of the chromatogram C ′ also changes.
The above calibration and adjustment procedures can be performed according to the instruction manual of the measuring instrument, but the general calibration procedure is not necessarily optimized for the analysis of individual substances to be measured. Additional corrections and adjustments may be required depending on the individual substance to be measured. This correction and adjustment requires specialized knowledge and experience, and an appropriate standard material, which complicates the work and causes a reduction in work efficiency.

  In the generated gas analysis, the sample is placed on the sample stage, and the sample is heated together with the sample stage in the heating furnace, or the sample is set on a holder and put into the heating furnace to generate a gas component. Analyzing. After the analysis, the sample stage is naturally cooled to about room temperature, the sample is replaced, and the next analysis is started by heating from around room temperature, but the waiting time until the sample stage is cooled is long, and the analysis work This leads to a decrease in overall efficiency.

Further, in the generated gas analysis, the generated gas component is introduced into a detection unit by flowing into a carrier gas such as nitrogen gas. However, if a large amount of gas components are generated and the gas concentration becomes too high, the detection signal exceeds the detection range of the detector and the detection signal is overscaled, resulting in inaccurate measurement.
Moreover, when using a mass spectrometer as a detector, the gas component is ionized in the front | former stage. However, if the gas component contains a subcomponent that is not the object of measurement, when the gas component is generated in a large amount, the subcomponent is ionized in a large amount, and the component to be measured that is originally intended to be ionized is sufficiently ionized. In other words, the detection signal to be measured is reduced (ion suppression).

  Therefore, the present invention has been made to solve the above-mentioned problems, and it is possible to easily correct a difference in detection sensitivity and a daily fluctuation, and to quantify a measurement object with high accuracy and high work efficiency. An object of the present invention is to provide a generated gas analysis method and a generated gas analyzer.

  In order to achieve the above object, the generated gas analysis method of the present invention includes a sample holder for holding a sample, and a heating unit that houses the sample holder in itself and generates the gas component by heating the sample. An ion source that ionizes the gas component generated by the heating unit to generate ions, a mass spectrometer that mass-analyzes the ions to detect the gas component, the heating unit, and the mass spectrometer, A gas flow path through which a mixed gas of the gas component and a carrier gas that guides the gas component to the mass spectrometer flows, and detects from the mass spectrometer Based on the signal, the discharge flow rate adjusting step for adjusting the discharge flow rate of the mixed gas to the outside so that the detection signal falls within a predetermined range, and the sample can be taken in and out outside the heating unit Discharge position A sample holder cooling step of cooling the sample holder by directly or indirectly contacting the sample holder with a cooling unit disposed outside the heating unit when the sample holder is moved; and Using a standard sample to be measured, (1) calibrate so that the spectral position corresponding to the mass-to-charge ratio m / z of the mass spectrum obtained for the gas component of the standard sample matches the reference spectral position (2 ) After the calibration of (1), from the chromatogram area S representing the intensity with respect to the retention time obtained for the gas component of the standard sample and the reference area Ss, the actual chromatogram of the gas component of the sample is obtained. A sensitivity correction coefficient Cs = Ss / S for measuring the area is calculated. (3) From the time t giving the maximum peak of the chromatogram and the reference time ts, the actual test is performed. Wherein the of having a correction step of calculating a heat correction coefficient H = t / ts for correcting the heating rate of the sample in the heating unit in the measurement of the gas component.

According to this generated gas analysis method, first, since the cooling unit comes into contact with the sample holder to cool the sample holder, the sample holder can be cooled more quickly than natural cooling, and the efficiency of analysis work is improved. be able to. As a result, it is possible to measure a large number of samples such as quality control. Further, since the sample holder is cooled outside the heating unit, the cooling unit is not exposed to the high temperature atmosphere in the heating unit, so that an excessive cooling capacity is not required, and the cooling unit and thus the entire apparatus can be downsized. Moreover, since the atmospheric temperature in the heating unit does not decrease due to cooling, it is not necessary to require extra energy and time for reheating the heating unit.
Furthermore, since there is no need to install a cooling unit in the heating unit, it is possible to reduce the size of the heating unit and thus the entire apparatus.

Furthermore, when a large amount of gas components are generated and the gas concentration becomes too high, the flow rate of the mixed gas discharged from the branch path to the outside is increased, and the flow rate of the mixed gas introduced from the gas flow path to the detection means side is increased. Decrease. Thereby, it can suppress that a detection signal exceeds the detection range of a detection means, and a measurement becomes inaccurate due to overscale.
At this time, it is only necessary to adjust the flow rate discharged from the branch path to the outside, and it is not necessary to increase the flow rate of the carrier gas. Therefore, without increasing the carrier gas supply capacity, Detection accuracy can be improved.

In addition to these, the above (1) calibrates the instrumental difference and daily fluctuation of the detection position of the mass spectrum of each gas component, so the chromatogram of each gas component in (2) and (3) is calibrated. It can be obtained with high accuracy.
Next, since the area of the chromatogram is affected by deterioration of the ion source that ionizes the gas component, measurement temperature, and the like, calibration according to (2) is required. Therefore, according to (2), the area of the chromatogram of the actual gas component can be corrected with the sensitivity correction coefficient Cs, and the gas component can be accurately quantified from this area.
Next, since the shape of the chromatogram (time t for giving the maximum peak) changes and the area of the chromatogram also changes when the heating rate (temperature increase rate) at the time of heating the sample changes, (3) Calibration by is required. Thus, by (2), by appropriately adjusting and measuring the heating conditions of the heating unit with the heating correction coefficient H, an accurate chromatogram can be obtained, and coupled with the correction by (2), More accurate quantification can be performed.
By calibrating these (2) to (3) by measuring one standard sample once before measuring the actual sample, the measurement object can be quantified with high accuracy, and machine differences and daily differences. Quantification is possible with high reproducibility while suppressing fluctuations.

When the measurement object includes a plurality of gas components, the heating correction coefficient H = Σai × ti / tsi (where i: natural number indicating each gas component i, ai: known heating sensitivity coefficient of each gas component i) Ti: time for giving the maximum peak of the chromatogram of each gas component i, tsi: reference time for giving the maximum peak of the chromatogram of each gas component i) may be calculated.
According to this generated gas analysis method, accurate determination of gas components can be performed even when the measurement object includes a plurality of the gas components.

The discharge flow rate adjustment step may be performed by measuring a predetermined test sample after the correction step.
According to this generated gas analysis method, since the discharge flow rate adjustment step is performed after the correction step is completed and the calibration is performed, the detection level of the mass spectrometer can be adjusted more accurately.

  The generated gas analyzer of the present invention includes a sample holder for holding a sample, a heating unit that accommodates the sample holder therein, and generates a gas component by heating the sample, and the heating unit generates the gas component. An ion source that ionizes a gas component to generate ions, a mass spectrometer that mass-analyzes the ions to detect the gas component, a connection between the heating unit and the mass spectrometer, and the gas component And a gas flow path through which a mixed gas with a carrier gas that guides the gas component to the mass spectrometer flows, the gas flow path has a branch path that is open to the outside, The branch path has a discharge flow rate adjusting mechanism for adjusting a discharge flow rate of the mixed gas to the outside, and the generated gas analyzer has a detection signal based on a detection signal from the mass spectrometer. Said to be within range A flow rate control unit for controlling the flow rate adjusting mechanism, a sample holder support unit for supporting the sample holder so as to be movable to a predetermined position inside and outside the heating unit, and an outer side of the heating unit. When the sample holder is moved to a discharge position where the sample can be taken in and out, a cooling unit that directly or indirectly contacts the sample holder to cool the sample holder, and the gas component is included as a measurement target. When a standard sample is used, (1) the spectral position corresponding to the mass-to-charge ratio m / z of the mass spectrum obtained for the gas component of the standard sample is calibrated so as to match the reference spectral position; (2) After the calibration of (1), the gas of the actual sample is obtained from the area S of the chromatogram representing the strength with respect to the retention time obtained for the gas component of the standard sample and the reference area Ss. The sensitivity correction coefficient Cs = Ss / S for measuring the area of the chromatogram of the minute is calculated. (3) From the time t giving the maximum peak of the chromatogram and the reference time ts, the gas of the actual sample is calculated. It further includes a calibration processing unit that calculates a heating correction coefficient H = t / ts for correcting the heating rate of the sample in the heating unit when measuring the components by a computer.

  ADVANTAGE OF THE INVENTION According to this invention, the measurement difference of a detection sensitivity of a generated gas analyzer, a daily fluctuation | variation, etc. can be correct | amended simply and a measurement object can be quantified with high precision and high work efficiency. Further, calibration and adjustment of an apparatus suitable for a measurement target substance can be performed without specialized knowledge and experience.

It is a perspective view which shows the structure of the generated gas analyzer which concerns on embodiment of this invention. It is a perspective view which shows the structure of a gas generation part. It is a longitudinal cross-sectional view which shows the structure of a gas generation part. It is a cross-sectional view which shows the structure of a gas generation part. It is a block diagram which shows the analysis operation | movement of the gas component by the generated gas analyzer. It is a figure which shows the discharge position and measurement position of a sample holder. It is a figure which shows an example of the heating pattern of a heating part, and the temperature change of a sample holder and a cooling part. It is a figure which shows the heat retention part of a gas flow path and a branch path. It is a figure which shows the forced exhaustion part of a branched path. It is a figure which shows the generated gas analysis method which concerns on embodiment of this invention. It is another figure which shows the generated gas analysis method which concerns on embodiment of this invention. It is a figure which shows an example which correct | amends the heating rate of the sample in a heating furnace with the heating correction coefficient H. FIG. It is a figure which shows the change of the shape of the chromatogram in mass spectrometry by the influence of the heating rate of a sample.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a perspective view showing a configuration of a generated gas analyzer 200 according to an embodiment of the present invention, FIG. 2 is a perspective view showing a configuration of a gas generator 100, and FIG. 3 is a shaft showing a configuration of the gas generator 100. 4 is a longitudinal sectional view taken along the center O, and FIG. 4 is a transverse sectional view taken along the axis O showing the configuration of the gas generating unit 100.
The generated gas analyzer 200 includes a main body unit 202 serving as a housing, a box-shaped gas generation unit mounting unit 204 mounted on the front surface of the main body unit 202, and a computer (control unit) 210 that controls the whole. The computer 210 includes a CPU that performs data processing, a storage unit that stores computer programs and data, a monitor, and an input unit such as a keyboard. The computer 210 corresponds to a “calibration processing unit” in the claims.

Inside the gas generator mounting portion 204, a cylindrical heating furnace (heating unit) 10, a sample holder 20, a cooling unit 30, a splitter 40 for branching the gas, and an ion source 50 are provided as one assembly. The gas generating part 100 which became is accommodated. Further, a mass spectrometer (detection means) 110 for analyzing a gas component generated by heating the sample is accommodated in the main body 202.
An opening 204h is provided from the upper surface to the front surface of the gas generator mounting portion 204. When the sample holder 20 is moved to a discharge position (described later) outside the heating furnace 10, it is positioned at the opening 204h. A sample can be taken in and out of the holder 20. In addition, a slit 204s is provided on the front surface of the gas generator mounting portion 204, and the sample holder 20 is moved in and out of the heating furnace 10 by moving the open / close handle 22H exposed to the outside from the slit 204s to the left and right. It is set to the discharge position of and the sample is taken in and out.
If the sample holder 20 is moved on a moving rail 204L (described later) by, for example, a stepping motor controlled by the computer 210, the function of moving the sample holder 20 in and out of the heating furnace 10 can be automated.

Next, the configuration of each part of the gas generation unit 100 will be described with reference to FIGS.
First, the heating furnace 10 is mounted on the mounting plate 204a of the gas generating section mounting portion 204 with the axis O horizontally, and has a substantially cylindrical heating chamber 12 that opens around the axis O, a heating block 14, and the like. And a heat insulation jacket 16.
A heating block 14 is disposed on the outer periphery of the heating chamber 12, and a heat insulation jacket 16 is disposed on the outer periphery of the heating block 14. The heating block 14 is made of aluminum, and is energized and heated by a pair of heating section heaters 14 a (see FIG. 4) extending along the axis O to the outside of the heating furnace 10. The heating unit heater 14a heats (heats) the heating block 14 and thus the atmosphere of the heating chamber 12 surrounded by the heating block 14 to a predetermined temperature.
The attachment plate 204 a extends in a direction perpendicular to the axis O, and the splitter 40 and the ion source 50 are attached to the heating furnace 10. Further, the ion source 50 is supported by a support column 204 b extending vertically from the gas generating unit mounting unit 204.

A splitter 40 is connected to the heating furnace 10 on the side opposite to the opening side (the right side in FIG. 3). Further, a carrier gas protection pipe 18 is connected to the lower side of the heating furnace 10, and a carrier gas that communicates with the lower surface of the heating chamber 12 and introduces the carrier gas C into the heating chamber 12 inside the carrier gas protection pipe 18. A flow path 18f is accommodated.
And although mentioned later in detail, the gas flow path 41 is connected to the end surface of the heating chamber 12 opposite to the opening side (the right side in FIG. 3), and the gas component G generated in the heating furnace 10 (heating chamber 12) The mixed gas M with the carrier gas C flows through the gas flow path 41.

The sample holder 20 includes a stage 22 that moves on a moving rail 204L attached to the inner upper surface of the gas generating part attaching part 204, a bracket 24c attached on the stage 22 and extending vertically, and a front face of the bracket 24c (FIG. 3). Heat insulating materials 24b and 26 attached to the left side), a sample holding portion 24a extending in the direction of the axis O from the bracket 24c to the heating chamber 12 side, a heater 27 embedded immediately below the sample holding portion 24a, and a heater 27 And a sample tray 28 that is disposed on the upper surface of the sample holder 24a and accommodates the sample.
Here, the moving rail 204L extends in the direction of the axis O (the left-right direction in FIG. 3), and the sample holder 20 advances and retreats in the direction of the axis O along with the stage 22. The opening / closing handle 22H is attached to the stage 22 while extending in a direction perpendicular to the direction of the axis O.
The moving rail 204L corresponds to a “sample holder support portion” in the claims.

The bracket 24c has a strip shape with the upper part being semicircular, and the heat insulating material 24b has a substantially cylindrical shape and is mounted on the front surface of the upper portion of the bracket 24c (see FIG. 2). The electrode 27a is taken out to the outside. The heat insulating material 26 has a substantially rectangular shape, and is attached to the front surface of the bracket 24c below the heat insulating material 24b. Further, the heat insulating material 26 is not attached below the bracket 24c, and the front surface of the bracket 24c is exposed to form a contact surface 24f.
The bracket 24 c has a slightly larger diameter than the heating chamber 12 and hermetically closes the heating chamber 12, and the sample holder 24 a is accommodated in the heating chamber 12.
Then, the sample placed on the sample tray 28 inside the heating chamber 12 is heated in the heating furnace 10 to generate a gas component G.

The cooling unit 30 is disposed outside the heating furnace 10 (on the left side of the heating furnace 10 in FIG. 3) so as to face the bracket 24 c of the sample holder 20. The cooling unit 30 includes a substantially rectangular cooling block 32 having a recess 32r, a cooling fin 34 connected to the lower surface of the cooling block 32, and an air cooling fan 36 connected to the lower surface of the cooling fin 34 to apply air to the cooling fin 34. Is provided.
As will be described in detail later, when the sample holder 20 moves to the left side of FIG. 3 in the direction of the axis O on the moving rail 204L and is discharged out of the heating furnace 10, the contact surface 24f of the bracket 24c becomes the cooling block. The bracket 24c is contacted while being accommodated in the recess 32r, and the heat of the bracket 24c is removed via the cooling block 32, thereby cooling the sample holder 20 (particularly the sample holding portion 24a).
In the present embodiment, the sample holder 20 (including the bracket 24c) and the cooling block 32 are both made of aluminum.

As shown in FIGS. 3 and 4, the splitter 40 includes the above-described gas flow path 41 that communicates with the heating chamber 12, a branch path 42 that communicates with the gas flow path 41, and is opened to the outside. A mass flow controller (discharge flow rate adjusting mechanism) 42a that is connected to the outlet side and adjusts the discharge flow rate of the mixed gas M from the branch passage 42 to the outside, and a housing portion 43 in which the gas flow channel 41 is opened. And a heat retaining part 44 surrounding the housing part 43.
As shown in FIG. 4, when viewed from above, the gas channel 41 communicates with the heating chamber 12 and extends in the direction of the axis O, then bends perpendicularly to the direction of the axis O, and further in the direction of the axis O. It has a crank shape that bends to reach the end portion 41e. Further, the diameter of the vicinity of the center of the gas flow path 41 extending perpendicularly to the direction of the axis O is increased to form a branch chamber 41M. The branch chamber 41M extends to the upper surface of the casing 43, and a branch path 42 having a slightly smaller diameter than the branch chamber 41M is fitted therein.
The gas flow path 41 may be a straight line that communicates with the heating chamber 12 and extends in the direction of the axis O to reach the terminal end portion 41e, and has various curves depending on the positional relationship between the heating chamber 12 and the ion source 50. Or a linear shape having an angle with the axis O.

  In this embodiment, the gas channel 41 has a diameter of about 2 mm, and the branch chamber 41M and the branch channel 42 have a diameter of about 1.5 mm. The ratio (split ratio) between the flow rate flowing through the gas flow path 41 to the terminal end 41e and the flow rate branched to the branch path 42 is determined by the resistance of each flow path. Can be spilled. The split ratio can be controlled by adjusting the opening of the mass flow controller 42a.

As shown in FIGS. 3 and 4, the ion source 50 includes a housing portion 53, a heat retaining portion 54 that surrounds the housing portion 53, a discharge needle 56, and a stay 55 that holds the discharge needle 56. The casing 53 is plate-shaped, and its plate surface is along the direction of the axis O, and a small hole 53C passes through the center. And the terminal part 41e of the gas flow path 41 passes through the inside of the housing part 53 and faces the side wall of the small hole 53C. On the other hand, the discharge needle 56 extends perpendicularly to the direction of the axis O and faces the small hole 53C.
Then, the gas component G is ionized by the discharge needle 56 in the mixed gas M introduced from the terminal portion 41 e to the vicinity of the small hole 53 </ b> C.
The ion source 50 is a known device, and in this embodiment, an atmospheric pressure chemical ionization (APCI) type is adopted. APCI is preferable because it does not easily cause fragmentation of the gas component G and does not generate a fragment peak, so that the measurement object can be identified from the peak mass without separation by chromatograph or the like.
The gas component G ionized by the ion source 50 is introduced into the mass spectrometer 110 together with the carrier gas C and analyzed.
The ion source 50 is accommodated inside the heat retaining unit 54.

FIG. 5 is a block diagram showing the gas component analysis operation by the generated gas analyzer 200.
The sample S is heated in the heating chamber 12 of the heating furnace 10 to generate a gas component G. The heating state (heating rate, maximum temperature, etc.) of the heating furnace 10 is controlled by the heating control unit 212 of the computer 210.
The gas component G is mixed with the carrier gas C introduced into the heating chamber 12 to become a mixed gas M and introduced into the splitter 40. The detection signal determination unit 214 of the computer 210 receives a detection signal from the detector 118 (described later) of the mass spectrometer 110.
The flow rate control unit 216 determines whether or not the peak intensity of the detection signal received from the detection signal determination unit 214 is outside the threshold range. When the flow rate is out of the range, the flow rate control unit 216 controls the opening degree of the mass flow controller 42 a, whereby the flow rate of the mixed gas M discharged from the branch path 42 to the outside in the splitter 40, and from the gas flow path 41. The flow rate of the mixed gas M introduced into the ion source 50 is adjusted, and the detection accuracy of the mass spectrometer 110 is kept optimal.

The mass spectrometer 110 includes a first pore 111 for introducing the gas component G ionized by the ion source 50, a second pore 112 through which the gas component G sequentially flows after the first pore 111, an ion guide 114, A quadrupole mass filter 116 and a detector 118 that detects a gas component G emitted from the quadrupole mass filter 116 are provided.
The quadrupole mass filter 116 is capable of mass scanning by changing the applied high-frequency voltage, generates a quadrupole electric field, and detects ions by oscillating the ions in the electric field. Since the quadrupole mass filter 116 forms a mass separator that allows only the gas component G in a specific mass range to pass therethrough, the detector 118 can identify and quantify the gas component G.
In addition, using the selected ion detection (SIM) mode that detects only ions with a specific mass-to-charge ratio (m / z) of the gas component to be measured, all-ion detection that detects ions with a certain range of mass-to-charge ratios Compared to the (scan) mode, the detection accuracy of the gas component to be measured is improved, which is preferable.

Next, with reference to FIG. 6, the cooling of the sample holder 20 which is one of the characteristic portions of the present invention will be described. In the present invention, the sample holder 20 is discharged to the outside of the heating furnace 10 shown in FIG. 6A through two stages 22 in the direction of the axis O through the stage 22, and the sample tray 28 is moved out of the heating furnace 10. It moves between the exposed discharge position and the measurement position housed in the heating furnace 10 shown in FIG.
First, at the discharge position shown in FIG. 6 (a), when the sample is taken in and out together with the sample pan 28, the sample pan 28 and the sample are replaced, and the next analysis is started by heating from around room temperature. At this time, if the sample holder 20 is hot, the sample is heated before the analysis is started when the sample tray 28 is installed. Therefore, in order to prevent this, the sample holder 20 is cooled. However, if the sample holder 20 is only naturally cooled, the waiting time until the sample holder 20 is cooled becomes long.

Therefore, as shown in FIG. 6A, when the sample holder 20 is moved to the discharge position, the contact surface 24f of the bracket 24c comes into contact with the concave portion (contact portion) 32r of the cooling block 32, thereby cooling. The heat of the bracket 24c is removed through the block 32, and the sample holder 20 is cooled.
Thereby, compared with natural cooling, the sample holder 20 can be cooled rapidly and the efficiency of analysis work can be improved. Further, since the sample holder 20 is cooled outside the heating furnace 10, the cooling unit 30 is not exposed to the high temperature atmosphere in the heating furnace 10, so that an excessive cooling capacity is not required, and the cooling unit 30 and thus the entire apparatus is downsized. Can be achieved. Further, since the temperature of the heating block 14 does not decrease due to cooling, extra energy and time are not required for reheating the heating furnace 10.
Furthermore, since it is not necessary to install the cooling unit 30 in the heating furnace 10, it is possible to reduce the size of the heating furnace 10, and thus the entire apparatus.

FIG. 7 shows an example of the heating pattern of the heating furnace 10 and the temperature change of the sample holder 20 and the cooling block 32 controlled by the heating control unit 212. Here, the holding temperature (maximum reached temperature) of the heating furnace 10 is set to 300 ° C., and the heating start temperature of the sample is set to 50 ° C. or less.
First, at time 0 (when the sample holder 20 moves to the discharge position P shown in FIG. 6A), the sample is set on the sample tray 28 of the sample holder 20 at 50 ° C. At this time, although the cooling block 32 is air-cooled to about room temperature in advance, the temperature rises to about 50 ° C. by contacting the sample holder 20, while the sample holder 20 is cooled to about 50 ° C. Moreover, the temperature in the heating furnace 10 is controlled to be 300 ° C. by the heating section heater 14a.
Next, when the sample holder 20 cooled to around 50 ° C. moves to the measurement position shown in FIG. 6A and is accommodated in the heating chamber 12, heating from the heating furnace 10 controlled to 300 ° C. The sample holder 20 is heated to 300 ° C. by the heating from the sample side heater 27 embedded immediately below the sample holding part 24a, and the generated gas component is analyzed. During the analysis, the cooling block 32 is cooled to less than 50 ° C. (around room temperature) by an air cooling fan 36 or the like described later.
When the analysis is completed, the sample holder 20 moves again to the discharge position P, and the above-described thermal cycle is repeated.

  Here, since the cooling unit 30 is disposed outside the heating furnace 10, the cooling unit 30 heated by cooling the sample holder 20 may be cooled slowly during the analysis. In particular, as shown in FIG. 7, the analysis time is generally longer than the cooling time. Therefore, it is not necessary to rapidly cool the cooling unit 30 by water cooling or the like, and it is sufficient to perform natural cooling by the cooling fins 34 or forced air cooling by the air cooling fan 36. The structure of 30 can be simplified, and the cost and size of the entire apparatus can be reduced.

As shown in FIG. 6 (a), when the cooling block 32 is viewed from above, a pair of protrusions 32p overhang from the both ends of the recess (contact part) 32r to the heating furnace 10 side in a U-shape. Each protrusion 32p surrounds the sample holder 20. In this way, the sample holder 20 can be moved back to the outside of the heating furnace 10 by retreating to the recess 32r, and the volume (heat capacity) of the cooling block 32 can be increased as compared with the case where each protrusion 32p is not provided. Since it increases, the cooling capacity is improved.
Moreover, in order to make the volume of the cooling block 32 the same without providing each protrusion 32p, it is necessary to move the cooling block 32 further outside (the left side in FIG. 6A) of the heating furnace 10, The overall dimensions become large. Therefore, further miniaturization of the entire apparatus can be achieved by providing the protrusion 32p.

  Further, when the ratio (C1 / C2) of the heat capacity C1 of the cooling block 32 and the heat capacity C2 of the sample holder 20 is 5 to 20, both the downsizing of the entire apparatus and the improvement of the cooling capacity can be realized. When the ratio is less than 5, the heat capacity C1 of the cooling block 32 may be reduced and the cooling capacity may be reduced. In some cases, the cooling capacity is insufficient, and the cooling cannot be sufficiently performed to the heating start temperature. If the ratio exceeds 20, the cooling block 32 may become too large and the entire apparatus may become large.

The cooling unit 30 preferably has an air cooling fan 36 or a cooling fin 34 for cooling the cooling block 32. In this way, the structure of the cooling unit 30 becomes simpler than the case where the cooling unit 30 is water-cooled or a pipe through which the refrigerant gas passes is attached to the cooling unit 30, thereby reducing the cost and size of the entire apparatus. it can.
In the case of a so-called heat sink in which the cooling fins 34 are attached to the cooling block 32, the cooling fins 34 are naturally cooled to cool the cooling block 32.
However, when the heat radiation from the cooling block 32 cannot catch up, it is preferable to attach an air cooling fan 36 to forcibly cool the cooling block 32. In this embodiment, as shown in FIGS. 2 and 6, the cooling fin 34 is connected to the lower surface of the cooling block 32, and the air cooling fan 36 is attached to the lower surface of the cooling fin 34.

In the present embodiment, the heating furnace 10 includes a heating unit heater 14a that heats the inside of the heating furnace (heating chamber 12) to a predetermined temperature, and a sample holder 20 heats the sample separately from the heating unit heater 14a. A side heater 27 is provided.
Thereby, the heating section heater 14a heats (maintains) the entire atmosphere in the heating furnace (heating chamber 12) to a predetermined temperature, thereby preventing the temperature of the sample in the heating chamber 12 from fluctuating. Further, the sample-side heater 27 disposed in the vicinity of the sample can heat the sample locally and quickly increase the sample temperature.
Note that, from the viewpoint of rapidly increasing the sample temperature, the sample-side heater 27 is preferably located in the vicinity of a member (for example, the sample tray 28) on which the sample is arranged. In particular, the sample-side heater 27 may be built in the sample holder 20 directly below the sample plate 28.

In the present invention, as shown in FIGS. 3 and 4 described above, the gas passage 41 has a branch passage 42 opened to the outside. Then, by controlling the opening degree of the mass flow controller 42 a attached to the branch path 42, the flow rate of the mixed gas M discharged from the branch path 42 to the outside, and hence the mixing introduced into the ion source 50 from the gas path 41. The flow rate of the gas M can be adjusted.
Therefore, when a large amount of gas components are generated and the gas concentration becomes too high, the flow rate of the mixed gas M discharged from the branch passage 42 to the outside is increased, and the mixed gas introduced from the gas flow passage 41 to the ion source 50 is increased. Reduce the flow rate of M. Thereby, it can suppress that a detection signal exceeds the detection range of the mass spectrometer 110, and a measurement becomes inaccurate due to overscale.
At this time, it is only necessary to adjust the flow rate discharged to the outside from the branch path 42, and it is not necessary to increase the flow rate of the carrier gas. Therefore, the gas component is not increased without increasing the supply capacity of the carrier gas and without increasing the size of the apparatus. Detection accuracy can be improved.

When a mass spectrometer is used as the analyzer, the gas component is ionized by the ion source 50 in the preceding stage, but when the above-mentioned ion suppression occurs due to ionization of the subcomponent when a large amount of gas component is generated. In some cases, the detection signal is lowered.
Therefore, when ion suppression occurs, the flow rate control unit 216 that has received the peak intensity of the detection signal of the mass spectrometer 110 from the detection signal determination unit 214 determines that the peak intensity of the detection signal is less than the threshold, and the mass flow controller 42a. A control signal for increasing the opening degree is transmitted to. Thereby, since the flow rate of the mixed gas M introduced into the ion source 50 is reduced, ionization of the subcomponent is suppressed, and the detection accuracy of the gas component can be improved by suppressing the decrease in the detection signal.

Note that it is not possible to determine whether or not ion suppression has occurred simply by looking at the peak intensity of the detection signal. In some cases, the content of the gas component to be measured is merely small. Therefore, it is necessary to determine the presence or absence of ion suppression from another phenomenon such as a high concentration of impurities other than the measurement target. This determination can be performed by an operator, or the presence or absence of ion suppression for each sample or gas component can be stored in a table as described later, and the flow rate control unit 216 can determine based on the table.
The flow rate controller 216 then branches the branch path 42 when the peak intensity of the detection signal exceeds the threshold value (overscale) or when the peak intensity is less than the threshold value (when it is determined that ion suppression is occurring). A control signal for increasing the flow rate of the mixed gas M discharged from the outside to the outside is generated.
In this case, for example, the presence / absence of ion suppression for each gas component is stored in a table, and the flow rate controller 216 refers to this table to determine the presence / absence of ion suppression and determines that ion suppression is occurring. In addition, a control signal for increasing the opening degree may be transmitted to the mass flow controller 42a. Further, each time the operator performs measurement, an input (selection button or the like) is input from the input unit of the computer 210 as to whether or not the measurement is a measurement in which ion suppression occurs, and the flow rate control unit 216 is based on this input signal. The peak intensity of the detection signal may be compared with a threshold value, and a control signal for increasing the opening degree may be transmitted to the mass flow controller 42a.
In addition, as a case where ion suppression is generated, a case where the measurement target is a phthalic acid ester and an auxiliary component is an additive such as phthalic acid is exemplified.

The gas component generated in the heating furnace 10 is cooled and condensed and trapped on the inner walls of the gas passage 41 and the branch passage 42 in the vicinity of the branch chamber 41M, and then vaporized again and measured by the ion source 50. Sometimes. In this case, not only does the measurement take a long time but the working efficiency decreases, but the condensed and re-vaporized gas component may affect the next measurement.
Therefore, as shown in FIG. 8, heat retaining portions 41H and 42H for heating or keeping the temperature around at least one of the gas channel 41 and the branch channel 42 near the branch chamber 41M may be provided. Thereby, it can suppress that a gas component is trapped on the inner wall of the gas flow path 41 or the branch path 42.
In FIG. 8, the heat retaining portion 41H is a coil heater that heats the periphery of the gas passage 41 near the branch chamber 41M, and the heat retaining portion 42H is a coil heater that heats the periphery of the branch passage 42 near the branch chamber 41M. .
In addition, the heat retaining portions 41H and 42H are not limited to heaters, and may be a heat insulating material or the like as long as the gas components can be prevented from solidifying. Moreover, at least one of the heat retaining portions 41H and 42H may be provided, or both may be provided.

On the other hand, when the gas component (mixed gas) is heated by the heat retaining units 41H and 42H, the mixed gas discharged from the branch path 42 and flowing through the mass flow controller 42a becomes high temperature, and a heat-resistant mass flow controller 42a may be required. .
Therefore, as shown in FIG. 9, an exhaust pump (forced exhaust part) 42p may be provided in the branch path 42 on the outlet side of the mass flow controller 42a instead of providing the heat retaining parts 41H and 42H. As a result, the mixed gas M flowing through the branch path 42 is forcibly exhausted, the pressure in the gas flow path 41 and the branch path 42 near the branch chamber 41M is lowered, and the trapped gas component is prevented from flowing back to the ion source 50 side. it can.

Next, the generated gas analysis method according to the embodiment of the present invention will be described with reference to FIG.
First, a standard sample including a gas component as a measurement target is prepared. In the present embodiment, the measurement target includes a plurality of gas components, and the standard sample includes the plurality of gas components (for example, four-component phthalates of DEHP, DBP, BBP, and DIBP subject to RoHS regulation). Although the content rate of each gas component contained in the standard sample is not limited, it is close to the content rate assumed for the actual gas component to be measured (for example, the RoHS regulation value of 4 components of DEHP, DBP, BBP, DIBP is 1000 ppm) Therefore, it is preferable that the contents of the four components are aligned in the same order. The content ratio is (mass of gas component) / (mass of the entire sample).
Then, calibration is performed according to the following procedure.

(1) Calibration is performed so that the spectrum position corresponding to the mass-to-charge ratio m / z of the mass spectrum obtained for each gas component of the standard sample matches the reference spectrum position. For example, in FIG. 10, the mass spectrometer 110 (in order that the spectrum positions of the mass spectra respectively obtained for the three gas components 1, 2, and 3 are within the allowable range 2L of the reference spectrum positions m1, m2, and m3. The setting (for example, high frequency voltage) of the quadrupole mass filter 116 is adjusted.
As shown in FIG. 11, the allowable range 2L is a range of ± L centering on each of the reference spectral positions m1, m2, and m3, and each gas component of the standard sample is within the allowable range 2L. It is sufficient that the spectral position of is within. In this embodiment, since the type of each gas component contained in the standard sample is determined in advance, the error from the reference spectrum position of multiple components is minimized as in general-purpose analysis in which the measurement target is not limited. This is because it is not necessary to perform such fitting. However, the method of matching each spectrum position with the reference spectrum position is not limited to the above, and it is of course possible to perform such fitting.
In this way, since the instrumental differences and daily fluctuations of the detection sensitivity of the spectral positions of the mass spectra of the respective gas components are calibrated, the following chromatograms of the respective gas components (2) and (3) can be obtained with high accuracy. be able to.

(2) After the calibration of (1), the sensitivity correction coefficient Cs = Ss / S is calculated from the area S of the chromatogram representing the intensity (ion intensity) with respect to the retention time obtained for the gas component of the standard sample and the reference area Ss. calculate. Cs becomes a correction coefficient when the area of the chromatogram of the gas component of the actual sample is subsequently measured. Since the area S of the chromatogram is affected by the deterioration of the ion source that ionizes the gas component, the measurement temperature, etc., calibration according to (2) is required.
For example, in FIG. 10, since the chromatograms C1, C2, and C3 are obtained for the three gas components 1, 2, and 3, respectively, the areas S1, S2, and C3 of the chromatograms C1, C2, and C3 are obtained by the CPU of the computer 210. S3 is obtained. On the other hand, reference areas Ss1, Ss2, and Ss3 are stored in the storage unit of the computer 210 for the gas components C1, C2, and C3, respectively. Therefore, the CPU calculates Cs (for example, Cs1 = Ss1 / S1 in the case of the gas component C1) for each of the gas components C1, C2, and C3, and multiplies the area of the chromatogram of the actual gas component C1 by Cs1. Consider the value as area. From this area, the gas component C1 can be accurately quantified.

(3) Heating of the sample in the heating furnace 10 (actually on the sample plate 28 whose temperature is being monitored) from the time t giving the maximum peak of the chromatograms C1, C2 and C3 and the reference time ts A heating correction coefficient H = t / ts for correcting the speed is calculated. H adjusts the heating rate of the sample in the heating furnace 10 when measuring the gas component of the actual sample thereafter. If the heating rate (temperature increase rate) when the sample is heated changes, the shape of the chromatogram (time t giving the maximum peak) changes and the area of the chromatogram also changes. Necessary.
For example, in FIG. 10, the time t1, t2, and t3 are obtained by the CPU for each of the chromatograms C1, C2, and C3, respectively. On the other hand, the reference times ts1, ts2, and ts3 are stored in the storage unit of the computer 210 for the gas components C1, C2, and C3, respectively. Therefore, the CPU calculates H = t / ts for each gas component C1, C2, C3.
By accurately adjusting the heating condition of the heating furnace 10 with H and measuring the gas component C1 of the actual sample, an accurate chromatogram can be obtained. Then, the value obtained by multiplying the area of the chromatogram by the sensitivity correction count Cs1 of the gas component C1 determined in (2) is used as the actual area value, whereby the gas component C1 can be more accurately quantified. it can. As a result, the heating capacity of the heating furnace 10 and the heater 27 of the generated gas analyzer 200, the measurement temperature, the difference in detection sensitivity, the daily fluctuation, etc. can be easily corrected by using a standard sample, and the measurement accuracy (especially the chromatogram) Gram area).
Actually, in the heating furnace 10, the temperature of the heating furnace 10 itself is uniformly held at a predetermined temperature by the heater 14 a, and the sample temperature is monitored by the resistance of the heater 27 directly below the sample dish 28. The heater 27 adjusts the heating rate of the sample according to the temperature. Therefore, “correcting the heating rate of the sample in the heating furnace” means correcting the heating rate of the portion (the heater 27 in this example) that changes the heating state according to at least the sample temperature.

Here, when the measurement target includes a plurality of gas components, it is calculated as H = Σai × ti / tsi. However, i is a natural number indicating each gas component i, and corresponds to the gas components 1, 2, and 3 in this embodiment. Ai is a known heating sensitivity coefficient of each gas component i, and indicates the ease of change of the peak time of each gas component (time t giving the maximum peak) with respect to the change of the heating rate. In the present embodiment, ai corresponds to the heating sensitivity coefficients a1, a2, and a3 for the gas components 1, 2, and 3, respectively. tsi is a reference time for giving the maximum peak of the chromatogram of each gas component i. In this embodiment, the reference times ts1, ts2, and so on for giving the maximum peaks of the chromatograms C1, C2, C3 for each gas component 1, 2, 3 are shown. This corresponds to ts3.
Therefore, H = (a1 × t1 / ts1) + (a2 × t2 / ts2) + (a3 × t3 / ts3).

FIG. 12 shows an example in which the heating rate of the sample in the heating furnace 10 is corrected by the heating correction coefficient H. For example, when the time t for giving the actual maximum peak is shorter than the reference time ts (when H <1), the heating rate is excessive, and it is necessary to lower the heating rate than the original heating pattern U. Therefore, the heating pattern U ′ is corrected by lowering the heating rate by multiplying the heating correction coefficient H by the inclination (heating rate) of the original heating program.
Generally, when the heating speed of the heater 27 is too fast, the gas concentration of the gas component increases rapidly, so that the ionization efficiency in the ion source cannot follow this, and the peak area value tends to decrease. Therefore, an accurate chromatogram can be obtained by correcting the heating pattern U ′.

In addition, when the processing of (1) to (3) is automatically performed by the calibration processing unit 210, the following is performed.
(1) Based on the received detection signal, the detection signal determination unit 214 has a mass so that the spectral position of each gas component of the standard sample is within m1, m2, m3 and the allowable range 2L set in the storage unit in advance. The setting (for example, high frequency voltage) of the analyzer 110 (quadrupole mass filter 116) is adjusted.
(2) The detection signal determination unit 214 calculates a sensitivity correction coefficient Cs based on the received detection signal and the reference areas Ss1, Ss2, and Ss3 set in the storage unit. The calculated Cs is stored in the storage unit.
(3) The detection signal determination unit 214 calculates the heating correction coefficient H = t / ts based on the received detection signal and the reference time ts set in the storage unit. The calculated H is stored in the storage unit.

  Next, in the mass analysis of the gas component of the actual sample, the heating control unit 212 corrects the heating rate of the sample in the heating furnace 10 based on H by the heater 27 control, and performs measurement in this state. Then, the detection signal determination unit 214 outputs a value obtained by multiplying the area of the obtained chromatogram by Cs1 as an area value.

After the calibration of the generated gas analyzer is completed as described above, a predetermined test sample is measured by the mass spectrometer 110, and the split ratio is determined so that the detection signal is within a predetermined range. it can. Then, an actual measurement sample may be measured based on this split ratio.
In addition, a standard sample and a test sample are set on an autosampler, which will be described later, and each position is designated, and after performing the above calibration based on the measured value of the standard sample, the measured value of the test sample is used. A split ratio may be determined, and an actual measurement sample may be measured based on the split ratio.

It goes without saying that the present invention is not limited to the above-described embodiment, but extends to various modifications and equivalents included in the spirit and scope of the present invention.
Examples of measurement targets include phthalate esters and bromide flame retardants (polybrominated biphenyls (PBB) and polybrominated diphenyl ethers (PBDE)) regulated by the European Specified Hazardous Substances Regulation (RoHS). It is not limited.
The configuration, shape, arrangement state, and the like of the heating furnace, sample holder, cooling unit, gas flow path, branching path, splitter, ion source, and mass spectrometer are not limited to the above examples. The method of calibrating the spectral position of the mass spectrum so as to match the reference spectral position is not limited to the above example, and a known method may be adopted.

  In addition, the generated gas analyzer of the present invention is provided with an autosampler for automatically and continuously inserting the sample into the heating unit, and a place for installing the standard sample is provided at a predetermined position of the autosampler. By measuring the standard sample once, the processes (1) to (3) can be automatically performed.

The sample holder support portion that supports the sample holder so as to be movable may be an arm or the like in addition to the above-described rail.
In addition to the case where the sample holder directly contacts the cooling unit, a separate member that is thermally connected to the sample holder is provided, and this separate member directly contacts the cooling unit (that is, the sample holder is indirectly connected to the cooling unit). For example).

10 Heating section (heating furnace)
DESCRIPTION OF SYMBOLS 20 Sample holder 30 Cooling part 41 Gas flow path 42 Branch path 42a Exhaust flow rate adjustment mechanism 41H, 42H Thermal insulation part 42p Forced exhaust part 50 Ion source 110 Mass spectrometer 200 Generating gas analyzer 204L Sample holder support part 210 Calibration processing part (computer) )
216 Flow rate control unit S Sample C Carrier gas G Gas component M Mixed gas C1, C2, C3 Chromatogram of gas component m1, m2, m3 Reference spectrum position

Claims (4)

A sample holder for holding the sample;
A heating unit that houses the sample holder therein and heats the sample to generate a gas component;
An ion source that ionizes the gas component generated in the heating unit to generate ions;
A mass spectrometer for mass-analyzing the ions to detect the gas component;
A generated gas analysis method comprising: a gas flow path that connects between the heating unit and the mass spectrometer and through which a mixed gas of the gas component and a carrier gas that guides the gas component to the mass spectrometer flows. In
Based on the detection signal from the mass spectrometer, a discharge flow rate adjustment step of adjusting the discharge flow rate to the outside of the mixed gas in the branch path so that the detection signal is within a predetermined range;
When the sample holder is moved to a discharge position where the sample can be taken in and out of the heating unit, the sample holder is brought into direct or indirect contact with a cooling unit disposed outside the heating unit. A sample holder cooling step for cooling the sample holder;
Using a standard sample containing the gas component as a measurement target,
(1) Calibrate so that the spectral position corresponding to the mass-to-charge ratio m / z of the mass spectrum obtained for the gas component of the standard sample matches the reference spectral position;
(2) After the calibration of (1), the chromatogram of the gas component of the actual sample is obtained from the area S of the chromatogram representing the strength with respect to the retention time obtained for the gas component of the standard sample and the reference area Ss. Calculate the sensitivity correction coefficient Cs = Ss / S when measuring the area of the gram,
(3) A heating correction coefficient H = for correcting the heating rate of the sample in the heating unit when measuring the actual gas component of the sample from the time t giving the maximum peak of the chromatogram and the reference time ts. a correction step of calculating t / ts;
A method for analyzing evolved gas, comprising: The measurement object includes a plurality of the gas components;
Heating correction coefficient H = Σai × ti / tsi (where i: natural number indicating each gas component i, ai: known heating sensitivity coefficient of each gas component i, ti: maximum peak of chromatogram of each gas component i) 2. The method for calibrating a generated gas analyzer according to claim 1, wherein a given time, tsi: a reference time for giving a maximum peak of a chromatogram of each gas component i) is calculated.   The method for calibrating a generated gas analyzer according to claim 1 or 2, wherein the discharge flow rate adjustment step is performed by measuring a predetermined test sample after the correction step. A sample holder for holding the sample;
A heating unit that houses the sample holder therein and heats the sample to generate a gas component;
An ion source that ionizes the gas component generated in the heating unit to generate ions;
A mass spectrometer for mass-analyzing the ions to detect the gas component;
A gas flow path that connects between the heating unit and the mass spectrometer and through which a mixed gas of the gas component and a carrier gas that guides the gas component to the mass spectrometer flows;
In the evolved gas analyzer equipped with
The gas flow path has a branch path opened to the outside, and the branch path has a discharge flow rate adjusting mechanism for adjusting a discharge flow rate of the mixed gas to the outside,
The generated gas analyzer comprises:
Based on the detection signal from the mass spectrometer, a flow rate control unit that controls the discharge flow rate adjustment mechanism so that the detection signal falls within a predetermined range;
A sample holder support unit that supports the sample holder so as to be movable to a predetermined position inside and outside the heating unit;
When the sample holder is disposed outside the heating unit and moved to a discharge position where the sample can be taken in and out of the heating unit, the sample holder is brought into direct or indirect contact with the sample holder. A cooling section for cooling;
When using a standard sample containing the gas component as a measurement target,
(1) Calibrate so that the spectral position corresponding to the mass-to-charge ratio m / z of the mass spectrum obtained for the gas component of the standard sample matches the reference spectral position;
(2) After the calibration of (1), the chromatogram of the gas component of the actual sample is obtained from the area S of the chromatogram representing the strength with respect to the retention time obtained for the gas component of the standard sample and the reference area Ss. Calculate the sensitivity correction coefficient Cs = Ss / S when measuring the area of the gram,
(3) A heating correction coefficient H = for correcting the heating rate of the sample in the heating unit when measuring the actual gas component of the sample from the time t giving the maximum peak of the chromatogram and the reference time ts. A generated gas analyzer further comprising a calibration processing unit that calculates t / ts by a computer.

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