Atomic absorption spectrophotometer and control method for atomic absorption spectrophotometer

Abstract

Provided is an atomic absorption spectrophotometer and a control method for an atomic absorption spectrophotometer. The atomic absorption spectrophotometer (10) includes: a furnace (2) that heats a sample; a heating power source (4) that includes a transformer (4a) that converts a voltage applied to the furnace (2) and supplies a current to the furnace (2); a measurement unit (3) that measures absorbance of the sample heated by the furnace (2); and a control unit (7) that controls the heating power source (4) and the measurement unit (3). The control unit (7) can set a temperature program of the furnace (2) according to the sample to be measured, predict a reaching temperature of the transformer (4a) in continuous measurement according to information of the set temperature program, and urge a user to change the temperature program when the predicted reaching temperature reaches a prescribed temperature.

Description

Technical Field

[0001] This disclosure relates to an atomic absorption spectrophotometer and a control method for the atomic absorption spectrophotometer. Background Technology

[0002] An atomic absorption spectrophotometer determines the concentration of the target element in the sample by passing a light beam through the atomic vapor of the sample atomized using a hollow cathode lamp. The concentration is determined based on the absorbance of the atoms being measured. Graphite furnace atomic absorption spectrophotometers are widely used as a type of atomic absorption spectrophotometer. Graphite furnace atomic absorption spectrophotometers offer advantages such as rapid sample heating and high absolute sensitivity. These spectrophotometers utilize a graphite furnace as an atomizer, which decomposes the compound in the sample into free atomic vapor.

[0003] In the atomic absorption spectrophotometer described above, a graphite tube is used in a graphite furnace, a sample is injected into the graphite tube, and the graphite tube is electrically heated by the Joule heating of the current flowing through it. In the case of electrically heating the graphite tube, it is known to use an alternating current method (Patent Document 1) to heat the graphite tube by using a transformer to allow alternating current to flow through it.

[0004] [Existing Technical Documents]

[0005] [Patent Literature]

[0006] Patent Document 1: Japanese Patent Application Publication No. 2020-101523 Summary of the Invention

[0007] [The problem the invention aims to solve]

[0008] In atomic absorption spectrophotometers using alternating current heating, the current flowing through the graphite tube varies significantly during a single measurement. Therefore, atomic absorption spectrophotometers consider using a transformer whose rated current is set to the maximum current reached during a single measurement. However, the time required to reach the maximum current is short within a single measurement, resulting in over-spec and increased manufacturing costs.

[0009] However, if a transformer with a rated current lower than its maximum current capacity is used, the atomic absorption spectrophotometer may experience increased heat generation within the transformer, potentially leading to malfunction. Therefore, when using a transformer with a rated current lower than its maximum current capacity in an atomic absorption spectrophotometer, it is advisable to incorporate protective mechanisms such as thermal fuses, automatic temperature controllers, or temperature monitoring devices like thermocouples and thermistors. However, if these protective mechanisms or temperature monitoring devices activate during a single measurement, the atomic absorption spectrophotometer may sometimes fail to acquire the measured data, resulting in incomplete measurement data.

[0010] This disclosure was made to solve the problems mentioned above, and aims to provide an atomic absorption spectrophotometer and a control method for the atomic absorption spectrophotometer, which can reduce manufacturing costs and perform stable measurements to avoid problems such as missing measurement data.

[0011] [Technical means to solve the problem]

[0012] The atomic absorption spectrophotometer disclosed herein includes: a furnace for heating a sample; a power supply including a transformer that converts the voltage applied to the furnace and supplies current to the furnace; a measuring unit for measuring the absorbance of the sample heated in the furnace; and a control unit for controlling the power supply and the measuring unit. The control unit is capable of setting a temperature program for the furnace according to the sample to be measured, predicting the arrival temperature of the transformer during continuous measurement based on information from the set temperature program, and prompting the user to change the temperature program when the predicted arrival temperature reaches a predetermined temperature.

[0013] The control method of the atomic absorption spectrophotometer disclosed herein includes the following steps: setting the furnace temperature program according to the sample to be measured; predicting the arrival temperature of the transformer during continuous measurement based on the information of the set temperature program; and prompting the user to change the temperature program when the predicted arrival temperature reaches a specified temperature.

[0014] [The effects of the invention]

[0015] The atomic absorption spectrophotometer and its control method described above can reduce manufacturing costs and ensure stable measurement to avoid problems such as missing measurement data. Attached Figure Description

[0016] Figure 1 This is a schematic diagram showing the structure of the atomic absorption spectrophotometer according to the embodiment.

[0017] Figure 2 This is a graph showing the temperature program and absorbance of the atomic absorption spectrophotometer according to the embodiment.

[0018] Figure 3 This is an example of a settings editing screen showing the temperature program settings of the atomic absorption spectrophotometer of the embodiment.

[0019] Figure 4 It is a graph showing the relationship between heating parameters and the reached temperature.

[0020] Figure 5 This is another example of a settings editing screen showing the temperature program settings for the atomic absorption spectrophotometer of the embodiment.

[0021] Figure 6 This is an example of a warning displayed on the settings editing screen when setting the temperature program of the atomic absorption spectrophotometer in the embodiment.

[0022] Figure 7 This is a flowchart illustrating a method for setting the temperature program of the atomic absorption spectrophotometer according to the embodiment.

[0023] [Explanation of Symbols]

[0024] 1: Light source

[0025] 2: Furnace

[0026] 2a: Sample loading inlet

[0027] 3: Measurement Section

[0028] 4: Heating power supply

[0029] 4a: Transformer

[0030] 5: Current sensor

[0031] 6: Light sensor

[0032] 7: Control Department

[0033] 10: Atomic Absorption Spectrophotometer

[0034] 15: External memory

[0035] 16: Operations Department

[0036] 17: Display Section Detailed Implementation

[0037] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the figures. Figure 1This is a schematic diagram showing the structure of the atomic absorption spectrophotometer according to the embodiment. The atomic absorption spectrophotometer 10 includes: a light source 1 such as a hollow cathode lamp, a furnace 2 as an atomization unit, a measuring unit 3 including a spectrometer and a photomultiplier tube, a heating power supply 4 that supplies current to the furnace 2, a current sensor 5 that measures the current supplied to the furnace 2, a light sensor 6 that measures the light from the furnace 2, and a control unit 7 that controls the heating power supply 4 and the measuring unit 3, etc.

[0038] Furnace 2 is, for example, a graphite tube with a sample inlet 2a at its center for loading a sample. The sample loaded through the sample inlet 2a is heated to atomize it. Alternatively, furnace 2 may contain materials other than graphite tubes. The heating power supply 4 that supplies current to furnace 2 includes a transformer 4a, which converts the voltage of an AC power supply (not shown) into a voltage applied to furnace 2. Furthermore, gases such as argon, nitrogen, or compressed air flow into the graphite tube from both ends and are discharged to the outside through the sample inlet, simultaneously promoting ashing and preventing oxidation of the graphite tube. Moreover, the temperature of furnace 2 is measured by detecting the amount of light emitted from the graphite tube using a photosensitive sensor 6.

[0039] The measuring unit 3 measures the absorbance of the sample heated in the furnace 2. For this purpose, it includes a spectrometer (not shown) and a photomultiplier tube. The spectrometer, for example, is a Czerny-Turner spectrometer, which includes an entrance slit, a mirror, a diffraction grating, and an exit slit. The absorbance measured by the photomultiplier tube is amplified by an amplifier and converted into a digital signal by an analog-to-digital (A / D) converter before being sent to the control unit 7.

[0040] The control unit 7 includes an external memory 15, an operation unit 16 with a keyboard, and a display unit 17 such as an LCD. Furthermore, the control unit 7 includes a central processing unit (CPU) as the control center, read-only memory (ROM) storing programs or control data for CPU execution, random access memory (RAM) functioning as the CPU's working area, a graphics processing unit (GPU) primarily performing image processing, and input / output interfaces for ensuring signal matching with peripheral devices. Additionally, the CPU or GPU may include a field-programmable gate array (FPGA).

[0041] The control unit 7 controls the heating power supply 4 to heat the furnace according to the temperature program described later, and uses the measuring unit 3 to measure the absorbance of the sample. Specifically, light containing glow line spectrum emitted from the light source 1 is guided into the measuring unit 3 through the inside of the graphite tube of the furnace 2. The guided light is split into a specified wavelength in the spectrometer of the measuring unit 3 and then reaches the photomultiplier tube. In addition, although not shown, appropriate focusing optical systems are respectively arranged between the light source 1 and the furnace 2, and between the furnace 2 and the measuring unit 3, to appropriately focus the light beam and guide it to the next section.

[0042] During sample determination, the sample is loaded into the graphite tube through the sample loading inlet 2a located in the center of the graphite tube. A large current flows through the graphite tube from the heating power supply 4 to heat the sample and atomize it. Light passing through the graphite tube is strongly absorbed by elements of a specific wavelength contained in the sample. The control unit 7 calculates the ratio of the light intensity when not subjected to this absorption to the light intensity when absorbed, and quantifies the sample based on this absorbance.

[0043] Furthermore, figures are used to illustrate in detail the temperature program and absorbance of the atomic absorption spectrophotometer 10. Figure 2 This is a graph showing the temperature program and absorbance of the atomic absorption spectrophotometer according to the embodiment. After the sample is loaded into the graphite tube of the furnace 2, when the user presses the start switch of the operation unit 16, the control unit 7 processes the sample according to the set temperature program. Figure 3 This diagram shows an example of a setting editing screen for setting the temperature program of the atomic absorption spectrophotometer according to the embodiment. The control unit 7 sets the temperature program according to a program pre-stored in ROM or external memory 15, etc. Figure 3 The settings and editing screen for setting the temperature program is displayed on the display unit 17.

[0044] The user sets the temperature, time, and heating mode, which are then controlled by the heating power supply 4. Figure 2 The furnace 2 is heated according to the temperature program pattern shown by the chain line. The control unit 7 controls the heating power supply 4 synchronously with the temperature program, following the sequence of drying-ashing-atomization-cleaning. During drying and ashing, an inert gas (e.g., argon) is introduced into the graphite tube, rapidly expelling water vapor generated during drying or fumes generated during ashing. Figure 3 The temperature program settings shown are divided into four stages for the drying process. Stage 1 is set to a heating mode (RAMP) that reaches 60°C in 3 seconds; Stage 2 is set to a heating mode (RAMP) that reaches 120°C in 25 seconds; Stage 3 is set to a heating mode (RAMP) that reaches 250°C in 10 seconds; and Stage 4 is set to a heating mode (RAMP) that reaches 1000°C in 10 seconds.

[0045] Figure 3 In the temperature program settings shown, stages 5 and 6 are set as the ashing period. In stage 5, the heating mode (STEP) is set to heat at 1000°C for 10 seconds, and in stage 6, the heating mode (STEP) is set to heat at 1000°C for 3 seconds.

[0046] After ashing, Figure 3 In the temperature program setting shown, a stage 7 is set as the atomization period. In stage 7, a heating mode (STEP) is set to heat the sample by maintaining 2700°C for 3 seconds. Therefore, the absorbance of the gas from the atomized sample inside the graphite tube by the light source 1 is measured using the measuring unit 3. During the atomization period, the measuring unit 3... Figure 2 As shown, the atomic absorption of a sample can be determined based on absorbance.

[0047] After atomization, in Figure 3 In the temperature program settings shown, a stage 8 is set as the cleaning period. In stage 8, the heating mode (STEP) is set to heat at 2700°C for 2 seconds. Subsequently, furnace 2 is heated according to the temperature program settings during a cooling period of approximately 15 to 30 seconds in order to measure the next sample.

[0048] In addition, in the control unit 7, the temperature of the furnace 2 is measured by the light sensor 6 and the current is measured by the current supplied from the heating power supply 4 to the furnace 2, thereby performing temperature control so that the temperature of the furnace 2 becomes the temperature set in the temperature program.

[0049] Thus, when heating the graphite tube by flowing current through it, the transformer 4a of the heating power supply 4 is used to allow alternating current to flow through the graphite tube to heat it. According to... Figure 3 As shown in the temperature program, the current flowing through the graphite tube varies significantly during a single measurement. Therefore, if an atomic absorption spectrophotometer uses a transformer whose rated current is set to the maximum current reached during a single measurement, the time required to reach the maximum current is short, resulting in out-of-specification performance and increased manufacturing costs.

[0050] However, if a transformer with a rated current lower than the maximum current is used, the atomic absorption spectrophotometer may experience increased heat generation within the transformer, potentially leading to malfunction. Therefore, in atomic absorption spectrophotometers using transformers with a rated current lower than the maximum current, it is essential to install protective mechanisms such as temperature fuses, automatic temperature controllers, or temperature monitoring mechanisms such as thermocouples or thermistors within the transformer.

[0051] Therefore, in the atomic absorption spectrophotometer 10 of this embodiment, a transformer with a rated current lower than the maximum current is used, and there is no need to install protection mechanisms such as blocking circuits or temperature monitoring mechanisms such as thermocouples and thermistors. Instead, the transformer's reaching temperature is predicted and controlled by a pre-set temperature program to ensure its correct operation. In other words, the atomic absorption spectrophotometer 10 does not require additional hardware mechanisms; instead, software control ensures the correct operation of the transformer.

[0052] In particular, when an atomic absorption spectrophotometer is equipped with a protection mechanism such as a blocking circuit or a temperature monitoring mechanism such as a thermocouple or thermistor, if the protection mechanism or temperature monitoring mechanism of the transformer is activated during a measurement, the atomic absorption spectrophotometer will be unable to acquire the measurement data, resulting in data loss. However, in the atomic absorption spectrophotometer 10, software control is used to ensure the correct operation of the transformer, thus avoiding the problem of data loss due to the inability to acquire measurement data.

[0053] Specifically, the control unit 7 predicts the arrival temperature of the transformer 4a during continuous measurement (operation) based on the temperature program information of the furnace 2 set before the start. When the predicted arrival temperature of the transformer 4a reaches or exceeds the limit temperature, it urges the user to change the temperature program.

[0054] Control unit 7 predicts the arrival temperature of transformer 4a based on a heating index. Here, the heating index is the integral of the heating temperature of furnace 2 as a function of heating time, divided by the sum of heating time and cooling time. That is, the heating index is... Figure 3 The value obtained by dividing the area of ​​the heating temperature and time shown in the temperature program by (heating time + cooling time). Figure 3 In the temperature program shown, the cooling time is set to 30 seconds, and the calculated heating index is approximately 385.

[0055] Experiments have shown that the heating index is strongly correlated with the temperature reached by transformer 4a during continuous measurement. Based on this relationship, the temperature reached by transformer 4a during continuous measurement can be uniquely predicted. Figure 4 It is a graph showing the relationship between heating parameters and the reached temperature. Figure 4 The vertical axis represents the temperature reached by transformer 4a, and the horizontal axis represents the heating index. Additionally, Figure 4The diagram illustrates the relationship between the heating index and the reached temperature for two transformers of different specifications. Specifically, the diagram showing the relationship between the heating index and the reached temperature varies depending on the specifications of the transformer used for heating power supply 4. The diagram showing the relationship between the heating index and the reached temperature for transformer 4a is Graph A, which can be represented by a linear function: y(reached temperature) = 0.2437x(heating index) + 25.701. Furthermore, the contribution rate (R) of this function... 2 The value is as high as 0.9997.

[0056] Chart B illustrates the relationship between the heating index and the reached temperature for a transformer of a different specification than transformer 4a. However, this is not the only example. Even for transformer 4a of the same specification, the chart showing the relationship between the heating index and the reached temperature may vary depending on the measurement mode, the driving time of transformer 4a, and other conditions (specified conditions). For example, if a different measurement mode with a different cooling time is used, the chart showing the relationship between the transformer's heating index and the reached temperature will be modified. Furthermore, for example, if the driving time of transformer 4a exceeds a specified time, the chart showing the relationship between the transformer's heating index and the reached temperature will be modified to account for the deterioration of transformer 4a.

[0057] Figure 4 The graph showing the relationship between the transformer's heating index and the reached temperature is a quantitative change curve representing the relationship between the heating index and the transformer's reached temperature, which is pre-stored in the external memory 15. This quantitative change curve can be stored either as a function of y (reached temperature) and x (heating index) or as a table summarizing the values ​​of y (reached temperature) and x (heating index). Furthermore, the control unit 7 changes the quantitative change curve (graph) representing the relationship between the heating index and the transformer's reached temperature according to predetermined conditions.

[0058] Figure 3 In the temperature program shown, using Figure 4 The diagram shown in Figure A indicates that the temperature reached by transformer 4a is less than 160°C (specified temperature). That is, Figure 4 In the chart A shown, when the temperature reached by transformer 4a is 160℃ (specified temperature), the heating index is 550. Therefore... Figure 3 The heating index for the temperature program shown is approximately 385, and the heating index for not reaching the specified temperature is 550. Thus, by utilizing the heating index of the temperature program, the control unit 7 can predict the arrival temperature of the transformer 4a during continuous measurement and determine whether the indirectly predicted arrival temperature reaches the specified temperature, thereby enabling the transformer overheat protection function through software. Furthermore, the heating index for the specified temperature, 550, can also be standardized to 100.

[0059] like Figure 3 The heating index for the temperature program shown is approximately 385, which can be determined according to... Figure 4 The chart A shown predicts that the arrival temperature of transformer 4a will be approximately 120°C. Furthermore, regarding the arrival temperature of transformer 4a, if the arrival temperature of transformer 4a can be predicted based on the temperature program information, the heating index can also be calculated.

[0060] Figure 5 This is another example of a settings editing screen showing the temperature program settings for the atomic absorption spectrophotometer 10 of the embodiment. Figure 5 The temperature program settings shown are also related to... Figure 3 Similarly, the temperature program shown is set in stages 1 to 4 during the drying process. In stage 1, a heating mode (RAMP) is set to reach 60°C in 3 seconds; in stage 2, a heating mode (RAMP) is set to reach 120°C in 25 seconds; in stage 3, a heating mode (RAMP) is set to reach 250°C in 10 seconds; and in stage 4, a heating mode (RAMP) is set to reach 1000°C in 10 seconds.

[0061] exist Figure 5 The temperature program settings shown are also related to... Figure 3 Similarly, the temperature program shown has stages 5 and 6 set during the ashing process. In stage 5, a heating mode (STEP) is set to heat at 1000°C for 10 seconds, and in stage 6, a heating mode (STEP) is set to heat at 1000°C for 3 seconds.

[0062] After ashing, Figure 5 The temperature program settings shown are also related to... Figure 3 Similarly, the temperature program shown also includes a stage 7 during the atomization period. In stage 7, a heating mode (STEP) is set to heat the material by maintaining 2700°C for 3 seconds.

[0063] After atomization, Figure 5 The temperature program settings shown are also related to... Figure 3 Similarly, the temperature program shown also includes stage 8 during the cleaning process. However, with Figure 3 The stage shown is different from stage 8, in Figure 5 Stage 8, as shown, is a heating mode (STEP) where heating is performed by maintaining 2700°C for 12 seconds. Therefore, in Figure 5 In the temperature program shown, the cooling time is set to 30 seconds, and the calculated heating index is approximately 603.

[0064] because Figure 5The heating index of the temperature program shown is approximately 603, which exceeds the specified heating index of 550. Therefore, the control unit 7 can predict the arrival temperature of the transformer 4a during continuous measurement and determines that the indirectly predicted arrival temperature has reached the specified temperature. Therefore, the control unit 7 urges the user to change the temperature program.

[0065] As an example of urging users to change their temperature settings, consider overlaying a warning window onto the temperature settings editing screen. Figure 6 This is an example of a warning displayed on the settings editing screen when setting the temperature program of the atomic absorption spectrophotometer 10 of the embodiment. Figure 6 The warning window displays information about excessive temperature rise and urges the user to change the temperature program to avoid this situation. Furthermore, the information urging the user to change the temperature program also suggests which setting needs to be changed. Additionally, the method by which the control unit 7 urges the user to change the temperature program is not limited to... Figure 6 The warning window shown can also be a warning sound or display the setting value that needs to be changed in red text.

[0066] Next, a flowchart will be used to explain in detail the method for setting the temperature program of the atomic absorption spectrophotometer 10. Figure 7 This is a flowchart illustrating the method for setting the temperature program of the atomic absorption spectrophotometer 10 according to the embodiment. First, the control unit 7 displays on the display unit 17. Figure 3 The setting editing screen for setting the temperature program is shown (step S11). The control unit 7 determines whether the input of the setting value for setting the temperature program has been accepted (step S12). Specifically, the control unit 7 accepts input of all setting values ​​(such as maximum number of stages, temperature, time, heating mode, etc.) required by the user to set the temperature program using the operation unit 16. If all have been accepted, it is determined that the input of the setting value has been accepted. Therefore, if it is determined that not all the input of the setting value has been accepted (no in step S12), the control unit 7 will return to step S11.

[0067] If it is determined that all input settings have been accepted (Yes in step S12), then control unit 7 calculates the heating index based on the temperature program's setpoint (step S13). Control unit 7 calculates the heating index based on the... Figure 3 The temperature program shown has a set value, and the cooling time is set to 30 seconds, resulting in a heating index of approximately 385.

[0068] Control unit 7 determines whether the predicted arrival temperature of transformer 4a (the arrival temperature of the heating index) based on the calculated heating index is above the specified temperature (step S14). Specifically, control unit 7 uses the calculated heating index and... Figure 4The chart shown is used to predict the arrival temperature of transformer 4a during continuous measurement, and it is determined whether the indirectly predicted arrival temperature reaches the specified temperature. If it is determined that the arrival temperature of the calculated heating index is not above the specified temperature (no in step S14), the control unit 7 starts the measurement by heating the furnace 2 based on the set temperature program (step S15). Figure 3 The heating index of the temperature program shown is about 385, which is less than the heating index of 550, which is the specified temperature. Therefore, the control unit 7 determines that the temperature reached by the calculated heating index is not above the specified temperature and starts the measurement.

[0069] On the other hand, if it is determined that the calculated heating index reaches a temperature above the specified temperature (yes in step S14), the control unit 7 displays a prompt to change the setting on the display unit 17. Specifically, the control unit 7 overlays the setting editing screen... Figure 6 The warning window shown.

[0070] Thus, the atomic absorption spectrophotometer 10 does not require special hardware; the overheat protection function of the transformer can be implemented through software. Therefore, the atomic absorption spectrophotometer 10 can accommodate a suitable transformer 4a while balancing safety and cost. Furthermore, the atomic absorption spectrophotometer 10 can prompt the user to change the temperature program before measurement begins if the transformer 4a becomes overheated due to continuous measurement, thus preventing measurement interruption due to the temperature program causing the transformer 4a to overheat after measurement has started. Of course, a hardware transformer protection mechanism or temperature monitoring mechanism can also be incorporated into the atomic absorption spectrophotometer 10 to ensure dual safety. Moreover, Figure 7 In the flowchart shown, the temperature program must be continuously changed until it is determined that the calculated heating index reaches a temperature that is not above the specified temperature. However, the atomic absorption spectrophotometer 10 can also start the measurement according to the user's judgment even if the calculated heating index reaches a temperature above the specified temperature.

[0071] [form]

[0072] Those skilled in the art will understand that the described embodiments are specific examples of the following forms.

[0073] (First item)

[0074] An atomic absorption spectrophotometer includes: a furnace for heating a sample; a power supply including a transformer that converts the voltage applied to the furnace and supplies current to the furnace; a measuring unit for measuring the absorbance of the sample heated in the furnace; and a control unit for controlling the power supply and the measuring unit. The control unit can set the temperature program of the furnace according to the sample to be measured, predict the arrival temperature of the transformer during continuous measurement based on the information of the set temperature program, and urge the user to change the temperature program when the predicted arrival temperature reaches a specified temperature.

[0075] According to the atomic absorption spectrophotometer described in the first item, when the predicted arrival temperature reaches the specified temperature, the user is urged to change the temperature program. This can reduce manufacturing costs and ensure stable measurement to avoid problems such as missing measurement data.

[0076] (Second item)

[0077] In the atomic absorption spectrophotometer described in the second item, the control unit calculates the value of the heating index obtained by dividing the integral value of the function of the furnace heating temperature and heating time by the sum of the heating time and cooling time based on the temperature program information, and predicts the arrival temperature of the transformer based on the heating index.

[0078] According to the atomic absorption spectrophotometer described in the second item, the value of the heating index is obtained based on the information of the temperature program, and the arrival temperature of the transformer is predicted based on the heating index, thus enabling accurate prediction of the arrival temperature of the transformer.

[0079] (Third item)

[0080] In the atomic absorption spectrophotometer described in the third item, the control unit pre-sets a quantitative change curve representing the relationship between the heating index and the transformer's arrival temperature, and predicts the transformer's arrival temperature based on the heating index obtained from the temperature program information and the set quantitative change curve.

[0081] According to the atomic absorption spectrophotometer described in the third item, the arrival temperature of the transformer is predicted based on the set quantitative change curve, thus enabling a more accurate prediction of the arrival temperature of the transformer.

[0082] (Item 4)

[0083] In the atomic absorption spectrophotometer described in the fourth item, the control unit changes the quantity change curve according to specified conditions.

[0084] According to the atomic absorption spectrophotometer described in the fourth item, the quantitative change curve is changed according to specified conditions, so the arrival temperature of the transformer can be predicted based on the quantitative change curve under specified conditions.

[0085] (Item 5)

[0086] In the atomic absorption spectrophotometer described in item 5, the specified conditions include at least one of the following: measurement mode, transformer specifications, and transformer drive time.

[0087] According to the atomic absorption spectrophotometer described in item 5, when the measurement mode is changed, the transformer specifications are changed, or the transformer driving time exceeds the specified time, the quantitative change curve is changed. Therefore, the arrival temperature of the transformer can be predicted based on the quantitative change curve under the specified conditions.

[0088] (Item 6)

[0089] In the atomic absorption spectrophotometer described in item six, the quantitative change curve is stored as a function of the heating index and the arrival temperature of the transformer.

[0090] According to the atomic absorption spectrophotometer described in item 6, the arrival temperature of a transformer can be predicted with good accuracy using a function of heating parameters and the arrival temperature of the transformer.

[0091] (Seventh item)

[0092] In the atomic absorption spectrophotometer described in item seven, the control unit urges the user to change the cooling time after heating according to the temperature program when the predicted arrival temperature reaches the specified temperature.

[0093] According to the atomic absorption spectrophotometer described in item 7, by urging the user to change the cooling time after heating according to the temperature program, stable measurements can be performed to avoid problems such as loss of measurement data.

[0094] (Item 8)

[0095] In the atomic absorption spectrophotometer described in item 8, the temperature program includes information on the temperature and time for each of the drying, ashing, atomization, and cleaning periods.

[0096] The atomic absorption spectrophotometer described in item 8 contains information on the temperature and time during the drying, ashing, atomization, and cleaning periods, thus enabling accurate prediction of the transformer's arrival temperature.

[0097] (Item 9)

[0098] In the atomic absorption spectrophotometer described in the ninth item, the control unit urges the user to change the temperature or time during the drying period of the temperature program when the predicted arrival temperature reaches the specified temperature.

[0099] According to the atomic absorption spectrophotometer described in item 9, stable measurements can be performed by urging the user to change the temperature or time during the drying process of the temperature program, so as to avoid problems such as loss of measurement data.

[0100] (Item 10)

[0101] In the atomic absorption spectrophotometer described in item 10, the furnace is a graphite tube.

[0102] According to the atomic absorption spectrophotometer described in item 10, the furnace is a graphite tube, which results in a fast heating rate and high absolute sensitivity.

[0103] (Item 11)

[0104] The control method described in the eleventh claim is a control method for an atomic absorption spectrophotometer, the atomic absorption spectrophotometer comprising: a furnace for heating a sample; a power supply including a transformer that converts the voltage applied to the furnace and supplies current to the furnace; a measuring unit for measuring the absorbance of the sample heated in the furnace; and a control unit for controlling the power supply and the measuring unit. The control method includes the following steps: setting a temperature program for the furnace according to the sample to be measured; predicting the arrival temperature of the transformer during continuous measurement based on information from the set temperature program; and prompting the user to change the temperature program when the predicted arrival temperature reaches a predetermined temperature.

[0105] According to the control method of the atomic absorption spectrophotometer described in item eleven, when the predicted arrival temperature reaches the specified temperature, the user is urged to change the temperature program. Therefore, it can reduce manufacturing costs and make stable measurements to avoid problems such as missing measurement data.

[0106] It should be understood that the embodiments disclosed herein are illustrative in all respects and not limiting. The scope of the invention is defined by the claims rather than the description, and is intended to include all modifications within the meaning and scope equivalent to the claims.

Claims

1. An atomic absorption spectrophotometer characterized by comprising: including: a furnace that heats a sample; a power supply that supplies current to the furnace, including a transformer that converts a voltage applied to the furnace; a measurement section that measures absorbance of the sample heated by the furnace; and a control section that controls the power supply and the measurement section, the control section being capable of setting a temperature program of the furnace according to a sample to be measured, the temperature program including information of temperature and time of each stage, calculating a heating index according to information of the temperature program set, the heating index being a value obtained by dividing an integral value of a function of heating temperature and heating time of the furnace by a sum of the heating time and a cooling time, and predicting a reaching temperature of the transformer in continuous measurement based on the heating index, urging a user to change the temperature program when the predicted reaching temperature reaches a prescribed temperature.

2. The atomic absorption spectrophotometer according to claim 1, wherein the control section sets a quantity change curve that represents a relationship between the heating index and the reaching temperature of the transformer in advance, the reaching temperature of the transformer is predicted based on the heating index and the quantity change curve set.

3. The atomic absorption spectrophotometer according to claim 2, wherein the control section changes the quantity change curve according to a prescribed condition.

4. The atomic absorption spectrophotometer according to claim 3, wherein the prescribed condition includes at least one of a measurement mode, a specification of the transformer, and a driving time of the transformer.

5. The atomic absorption spectrophotometer according to any one of claims 2 to 4, wherein the quantity change curve is stored as a function of the heating index and the reaching temperature of the transformer.

6. The atomic absorption spectrophotometer according to claim 1, wherein the control section urges a user to change the cooling time after heating performed in accordance with the temperature program when the predicted reaching temperature reaches the prescribed temperature.

7. The atomic absorption spectrophotometer according to any one of claims 1 to 4, wherein the information of temperature and time of each stage of the temperature program includes information of temperature and time of each of a drying period, an ashing period, an atomization period, and a cleaning period.

8. The atomic absorption spectrophotometer according to claim 7, wherein the control section urges a user to change temperature or time of the drying period of the temperature program when the predicted reaching temperature reaches the prescribed temperature.

9. The atomic absorption spectrophotometer according to any one of claims 1 to 4, wherein the furnace is a graphite tube. The atomic absorption spectrophotometer includes: a furnace that heats a sample; a power supply that supplies current to the furnace, including a transformer that converts a voltage applied to the furnace; a measurement section that measures absorbance of the sample heated by the furnace; and a control section that controls the power supply and the measurement section, the control method including the steps of:

10. A control method of an atomic absorption spectrophotometer, characterized by, setting a temperature program of the furnace according to a sample to be measured, the temperature program including information of temperature and time of each stage, ​ obtaining a heating index from information of the temperature program set, the heating index being a value obtained by dividing an integral value of a function of a heating temperature of the furnace and a heating time by a sum of the heating time and a cooling time, and predicting a reaching temperature of the transformer in the continuous measurement based on the heating index; and when the predicted reaching temperature reaches a prescribed temperature, urging a user to change the temperature program.

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