Spectrophotometer, spectrophotometric measurement method, and program

Abstract

The baseline is appropriately averaged without slowing down the wavelength change speed during actual sample measurement, thereby obtaining highly accurate analysis results. [Solution] The device comprises a light source 1, a spectroscope 2 that disperses light from the light source 1, a beam splitter 3 that separates the optical path of the light dispersed by the spectroscope 2 into a sample-side beam 4 and a reference-side beam 8, a sample-side detector 14 that detects the sample-side beam 4 that has passed through the measurement sample, and a reference-side detector 15 that detects the reference-side beam 8 that has passed through the reference sample, and a control unit 18 that calculates the spectral intensity distribution of the sample-side beam from the measurement sample and the spectral intensity distribution of the reference-side beam from the reference sample based on the measurement sample signal of the sample-side detector 14 and the reference sample signal of the reference-side detector 15, and the control unit 18 repeatedly measures the baseline multiple times at the wavelength change speed during actual measurement of the measurement sample, and performs an averaging process to average the integrated values ​​of the multiple baseline measurements.

Description

[Technical Field]

[0001] The present invention relates to a spectrophotometer, a spectrophotometric measurement method, and a program. [Background technology]

[0002] When performing spectroscopic analysis of a sample using a spectrophotometer, the resulting measurement data (spectral intensity distribution) is contaminated with background intensities due to various factors, such as the spectrophotometer's installation environment, electrical noise, and absorption by the target substance. To eliminate the effects of this background intensities, a common method is to subtract a baseline obtained by measuring without a sample from the sample measurement data obtained by measuring with a sample. Furthermore, the light emitted from the light source in a spectrophotometer has different energy values ​​for each wavelength range. Especially at low energy values, even slight variations in the energy value can significantly affect the measurement results (transmittance, absorbance, reflectance, etc.). Therefore, accurate baseline determination is essential for high-precision measurements.

[0003] As a technique for determining such a baseline, for example, Patent Document 1 describes a baseline setting method for a gas chromatograph that detects sample gas transported by a carrier gas and analyzes its components. In this gas chromatograph analysis method, only carrier gas is passed through a column, and fluctuations in the baseline voltage are stored. Each component of the sample gas is measured based on the stored fluctuations in the baseline voltage. The baseline is set using the average value of the baseline voltage, which fluctuates due to gain switching and other factors within the measurement period. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 5-113436 Summary of the Invention [Problem to be solved by the invention]

[0005] However, as mentioned above, the light source used in the spectrophotometer has different energy values ​​for each wavelength range, and therefore the baseline also needs to be averaged according to the wavelength range of the energy value. For this reason, it is difficult to simply apply the averaging and correction technique described in Patent Document 1 to correcting the baseline in a spectrophotometer.

[0006] Another approach to addressing temporal changes in the amount of light from the light source (noise) is to slow down the scan speed (wavelength change speed) that changes the wavelength of the light extracted from the spectrometer, thereby increasing the integrated value in baseline measurement. However, unless the measurement conditions for the baseline measurement and the actual sample measurement are kept as consistent as possible, it is difficult to ensure a more accurate baseline correction value, and the correction accuracy based on the baseline cannot be maintained due to the superimposition of noise. This means that the actual measurement must also be set to the same slow wavelength change speed as the baseline measurement, which poses the problem of longer measurement times.

[0007] Therefore, an object of the present invention is to provide a spectrophotometer, a spectrophotometric measurement method, and a program that are capable of properly averaging the baseline and obtaining highly accurate analysis results without slowing down the wavelength change rate during actual sample measurement. [Means for solving the problem]

[0008] The present invention comprises the following configurations. (1) a light source; a spectrometer that splits the light from the light source at a specified wavelength change rate; a detector that detects the sample-transmitted light beam that has been dispersed by the spectrometer and passed through the measurement sample for each wavelength; a control unit that determines a spectral intensity distribution of the light beam that has passed through the sample based on a measurement sample signal of the light beam that has passed through the sample output from the detector; Equipped with the control unit repeatedly measures a baseline indicating the background intensity of the measurement sample signal for each wavelength at the wavelength change rate during measurement of the measurement sample, and calculates an averaged baseline by averaging the multiple measured values ​​of the baseline for each wavelength; correcting the spectral intensity distribution using the averaged baseline; Spectrophotometer. (2) A spectrophotometric measurement method for spectrally separating light from a light source at a specified wavelength change rate, detecting a sample-transmitted beam of light for each wavelength that has passed through a measurement sample, and determining a spectral intensity distribution of the sample-transmitted beam of light based on the detected measurement sample signal of the sample-transmitted beam of light, repeating a baseline measurement indicating the background intensity of the measurement sample signal for each wavelength a plurality of times at the same wavelength change rate as the wavelength change rate when measuring the spectral intensity distribution; A plurality of measurements of the baselines repeatedly measured are averaged for each wavelength to obtain an average baseline; correcting the spectral intensity distribution using the averaged baseline; Spectrophotometric measurement method. (3) A program for executing a spectrophotometric measurement procedure that disperses light from a light source at a specified wavelength change rate, detects a sample-passing beam for each wavelength that has passed through a measurement sample, and determines a spectral intensity distribution of the sample-passing beam based on the detected measurement sample signal of the sample-passing beam, On the computer, a step of repeatedly measuring a baseline indicating the background intensity of the measurement sample signal for each wavelength at the same wavelength change rate as the wavelength change rate when measuring the spectral intensity distribution; a step of obtaining an average baseline by averaging a plurality of measurements of the baseline repeatedly measured for each wavelength; correcting the spectral intensity distribution using the averaged baseline; A program to execute. [Effects of the Invention]

[0009] According to the present invention, in measuring a sample using a spectrophotometer, the baseline can be appropriately averaged without slowing down the wavelength change speed in the actual measurement of the sample, thereby obtaining highly accurate analysis results. [Brief explanation of the drawings]

[0010] [Figure 1] FIG. 1 is a schematic diagram of a spectrophotometer according to the first embodiment. [Figure 2] FIG. 2 is a flowchart illustrating measurement using a spectrophotometer. [Figure 3] FIG. 3 is a flowchart illustrating the baseline averaging process. [Figure 4] FIG. 4 is a schematic diagram showing a part of the input screen on the display unit. [Figure 5] FIG. 5 is a flowchart illustrating the baseline averaging process in the second embodiment. [Figure 6] FIG. 6 is a graph showing an example of energy values ​​in the type information of the light source. DETAILED DESCRIPTION OF THE INVENTION

[0011] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. (First embodiment) Fig. 1 is a schematic diagram of a spectrophotometer 100 according to the first embodiment. In Fig. 1, optical paths are indicated by solid arrows, and signal processing flows are indicated by dotted arrows. The spectrophotometer 100 according to this embodiment includes a light source 1, a spectroscope 2, a beam splitter 3, reflecting mirrors 5, 6, and 7, a sample chamber 11, a sample mounting unit 9, a reference sample mounting unit 10, a sample-side detector (detector) 14, a reference-side detector (detector) 15, a sample-side converter 16, a reference-side converter 17, a control unit 18, a display unit 22, and an instruction input unit 23.

[0012] The light source 1 is, for example, a white light source, and the emitted light is dispersed by a spectroscope 2 as shown by the solid arrows in Figure 1 to extract specific wavelengths, and then separated by a beam splitter 3 into a sample-side beam 4 and a reference-side beam 8.

[0013] The spectrometer 2 includes, for example, a diffraction grating 31 and a motor 32 that rotates and scans the diffraction grating 31. The spectrometer 2 rotates the diffraction grating 31 by driving the motor 32, thereby changing the wavelength of the light extracted from the light source 1. The speed of this rotational movement of the diffraction grating 31 determines the speed at which the wavelength of the extracted light is changed. Note that, without using the spectrometer 2, light of a desired wavelength may be extracted using another configuration, such as by using a wavelength-tunable laser device as the light source 1 that can freely change the wavelength of laser light.

[0014] A sample mounting section 9, in which a sample to be measured is mounted, and a reference sample mounting section 10, in which a reference sample is mounted, are arranged in the sample chamber 11. Note that the sample chamber 11 is provided with windows (not shown) so that light irradiated from the reflecting mirrors 6 and 7 is irradiated onto the sample mounting section 9 and the reference sample mounting section 10, respectively, and the light passing through these sections is directed toward the sample-side detector 14 and the reference-side detector 15.

[0015] The sample-side beam 4 that passes through the beam splitter 3 is reflected by reflecting mirrors 5 and 6, and the reference-side beam 8 that is reflected by the beam splitter 3 is reflected by reflecting mirror 7 and each is guided to the sample chamber 11. The sample-side beam 4 passes through a measurement sample placed in the sample mounting section 9 in the sample chamber 11, and the transmitted light of the measurement sample is detected by the sample-side detector 14. On the other hand, the reference-side beam 8 passes through a reference sample placed in the reference sample mounting section 10 in the sample chamber 11, and is detected by the reference-side detector 15.

[0016] The sample-side converter 16 and the reference-side converter 17 are equipped with a signal amplification amplifier and an A / D converter, and process the signals from the sample-side detector 14 and the reference-side detector 15, and output them to the control unit 18. In other words, the amount of transmitted light of the sample-side light beam 4 detected by the sample-side detector 14 and the amount of transmitted light of the reference-side light beam 8 detected by the reference-side detector 15 are output as electrical signals, and then amplified and converted from analog to digital signals by the sample-side converter 16 and the reference-side converter 17, respectively, and sent to the control unit 18.

[0017] The control unit 18 performs overall control of the spectrophotometer 100. For example, the control unit 18 issues instructions for measuring the sample placed in the sample chamber 11 and performs analytical processing based on the obtained measurement results. The control unit 18 is a computer device that includes, for example, a processor such as a CPU (Central Processing Unit) or a GPU (Graphical Processing Unit), and a storage device including a storage device such as an HDD (Hard Disk Drive) or an SSD (Solid State Drive), a ROM (Read Only Memory), and a RAM (Random Access Memory). The control unit 18 realizes various functions by reading and executing various programs stored in the storage device.

[0018] Furthermore, control unit 18 receives setting parameters and various information via instruction input unit 23 and operates spectrophotometer 100 based on that information. Note that in this embodiment, control unit 18 for controlling each part of spectrophotometer 100 is described as comprehensively controlling each part, but a configuration in which a separate control unit is provided for each part and spectrophotometer 100 operates by linking these units together may also be used. Alternatively, control unit 18 and a measurement unit including an optical system may be configured independently as individual devices and linking these units together to perform the operations described below.

[0019] Display unit 22 includes a display device such as a liquid crystal display panel. Measurement results and information about each unit are displayed on the display device based on display signal 21 processed by control unit 18. A user of spectrophotometer 100 can grasp information such as measurement results and the status of the device from the contents displayed on display unit 22.

[0020] The instruction input unit 23 has a UI (User Interface) for receiving various instructions and settings from the user of the spectrophotometer 100, and may be a touch panel display or the like integrated with the display unit 22. The instruction input unit 23 may also include input devices such as a keyboard and a mouse.

[0021] In the spectrophotometer 100 configured as described above, light of a desired wavelength is extracted from the light emitted from the light source 1 by the spectroscope 2 and irradiated onto the measurement sample. A predetermined calculation is then performed using the amount of transmitted light detected by the sample-side detector 14 and the amount of light detected by the reference-side detector 15 to determine the spectral intensity distribution. From this spectral intensity distribution, the amount of absorbed, transmitted, and reflected light of the measurement sample can be determined. For example, in the case of solution absorption measurement, the user can determine the concentration of the unknown sample by comparing the absorbance obtained from a solution sample containing a certain component at a known concentration with the absorbance of a sample with an unknown concentration.

[0022] That is, the control unit 18 determines the spectral intensity distribution of the measurement sample based on the digital signals output from the sample-side converter 16 and the reference-side converter 17, and calculates the absorbance, transmittance, reflectance, sample-side energy value, reference-side energy value, etc. of the measurement sample according to the specified instructions. Instruction information such as conditions for operating the spectrophotometer 100 is input to the spectrophotometer 100 by a user operating the instruction input unit 23. The control unit 18 transmits an apparatus control signal 20 in accordance with the instruction information input from the instruction input unit 23, and controls each part such as the light source 1 and the spectrometer 2.

[0023] The spectrophotometer 100 shown in Figure 1 is a double-beam spectrophotometer that performs measurements by irradiating a measurement sample and a reference sample with a sample-side light beam 4 and a reference-side light beam 8. This double-beam spectrophotometer 100 is equipped with a reference sample mounting section, and measures the measurement sample based on the measurement data of the reference sample. Measurements using the double-beam system can avoid the effects of fluctuations in the energy value of the light source 1 over measurement time, enabling stable measurements over long periods of time.

[0024] Furthermore, the spectrophotometer 100 performs baseline measurement separately from the above-described sample measurement. The baseline is a profile showing the background intensity of the measured sample signal for each wavelength, and is data for correcting the spectral intensity distribution measured for the sample. Specifically, the transmitted light intensity value obtained by performing spectroscopic measurement without placing a sample on the sample mounting unit 9 and the reference sample mounting unit 10 is acquired as baseline information. This baseline measurement may also be performed by placing a blank sample such as pure water on the sample mounting unit 9 and the reference sample mounting unit 10.

[0025] In the double-beam spectrophotometer 100, the corrected measurement value is calculated based on, for example, equation (1). Measurement value = (Is / Ir) / (Bs / Br)…(1) however, Is: Measured value of the luminous flux on the sample side Ir: Reference side luminous flux measurement value Bs: Baseline value of the sample side luminous flux Br: Baseline value of reference side luminous flux

[0026] Next, an example of the procedure for spectroscopic measurement using the above-described spectrophotometer 100 will be described. 2 is a flowchart of the basic measurement control process executed by the control unit 18. In the procedure shown here, the baseline measurement described above is assumed to be performed separately, and therefore the baseline measurement is omitted.

[0027] First, when the power switch (not shown) of the spectrophotometer 100 is turned on (step 1, hereinafter also referred to as "S1"), the spectrophotometer 100 starts up (S2). Then, the light source 1, the spectroscope 2, the beam splitter 3, the sample-side detector 14, the reference-side detector 15, the sample-side converter 16, the reference-side converter 17, the control unit 18, and the display unit 22 become operational, and the device control process starts.

[0028] The user operates the instruction input unit 23 in accordance with the measurement sample to set measurement conditions for operating the spectrophotometer 100, such as the wavelength range of light to be irradiated onto the measurement sample, thereby setting each part, such as the light source 1, spectroscope 2, and beam splitter 3, to the desired conditions (S3).

[0029] Then, guidance for the user to place a sample in the sample placement section 9 of the sample chamber 11 is displayed on the display section 22 (S4).

[0030] After the user operates according to the guidance, data acquisition begins (S5). After acquiring the predetermined data (S6), if there is a next measurement under the measurement conditions set in step S3, the process returns to step S4 (S7). If there is no next measurement, the measurement ends (S8). The measurement results are displayed on the display unit 22 as described above.

[0031] A deuterium discharge tube, a tungsten iodine lamp, or a xenon flash lamp is generally used as the light source 1 of the spectrophotometer 100. In particular, a xenon flash lamp generates little heat and can be pulsed (intermittently lit), allowing it to be turned on and off frequently depending on the situation.

[0032] However, the energy value of light from these light sources varies depending on the wavelength range, and fluctuations in this energy value can adversely affect measurements of transmittance, absorbance, and reflectance. The above-mentioned effects of fluctuations in energy value are particularly noticeable in wavelength ranges with low energy values.

[0033] For example, when a sample with an energy value of 80 is measured with a baseline at an energy value of 100, the transmittance is 80%, and when a sample with an energy value of 80 is measured with a baseline at an energy value of 99, the transmittance is 80.8%. In contrast, when a sample with an energy value of 4 is measured with a baseline at an energy value of 5, the transmittance is 80%, and when a sample with an energy value of 4 is measured with a baseline at an energy value of 4, the transmittance is 100%. Thus, in wavelength ranges with large energy values, the effect on transmittance, absorbance, and reflectance due to fluctuations in energy value is small, but in wavelength ranges with small energy values, the effect is large, resulting in large errors in the measurement results.

[0034] Therefore, in spectrophotometer 100 of this configuration, when measuring the baseline, control unit 18 performs averaging processing for each wavelength of the baseline. This makes it possible to suppress the occurrence of errors when correcting the measured values ​​in actual measurements using the baseline.

[0035] Next, the averaging process performed by the control unit 18 during baseline measurement will be described. This baseline measurement may be performed by a program stored in the memory unit of the control unit 18, or may be performed manually. Furthermore, the baseline measurement may be performed in conjunction with the actual measurement of the measurement sample, or may be performed in advance of the actual measurement, and the timing of its execution is not limited. Figure 3 is a flowchart of the averaging process performed by the control unit 18 during baseline measurement.

[0036] The user operates the instruction input unit 23 to input the start wavelength and end wavelength of the baseline measurement to set the measurement wavelength range (S11). This measurement wavelength range may be the same as the set value of the measurement wavelength range in the actual measurement. The user also operates the instruction input unit 23 to input and set the number of measurements N of the baseline measurement (S12). Note that when the baseline measurement is performed in conjunction with the actual measurement, the above-mentioned measurement wavelength range and number of measurements N are set when the conditions for the actual measurement are set.

[0037] FIG. 4 shows an example of a portion of the input screen for setting items on the display unit 22. The input screen includes an item input field Ds for the start wavelength Ws and an item input field De for the end wavelength We of the actual measurement and baseline measurement. The input screen also includes an item input field Dn for the number of measurements N of the baseline measurement. The user operates the instruction input unit 23 to input the start wavelength Ws into the item input field Ds, the end wavelength We into the item input field De, and the number of measurements N into the item input field Dn. Although FIG. 4 displays "Ws," "We," and "N," numerical values ​​are actually displayed. The user can also easily increase or decrease the numerical values ​​by pressing the "+" and "-" buttons on the input screen with an input device such as a mouse.

[0038] After inputting the start wavelength Ws and end wavelength We of the baseline measurement wavelength range and the number of baseline measurements N, the user operates the instruction input unit 23 to start baseline measurement. The control unit 18 then continuously measures the baseline in the input wavelength range, for example, from the long wavelength side to the short wavelength side. The control unit 18 repeats the baseline measurement for the set number of measurements N for the wavelength range from the set start wavelength Ws to the end wavelength We (S13). Here, the control unit 18 sets the scanning speed when repeatedly measuring the baseline for the number of measurements N, i.e., the wavelength change speed at which the diffraction grating 31 is rotated to change the wavelength of the extracted light, to the same speed as the wavelength change speed (scanning speed) during actual measurement when measuring the measurement sample. This allows the baseline measurement conditions to be adjusted to the measurement conditions during actual measurement.

[0039] The control unit 18 averages the baselines of the measured wavelength range for each wavelength by a method such as measuring the baseline of a specific measurement wavelength range N times and dividing the integrated value of the measurement data obtained by the number of measurements N (S14).

[0040] As described above, according to the first embodiment, by repeatedly measuring the baseline in a specified wavelength range multiple times and averaging the results, it is possible to appropriately average the baseline that is affected by fluctuations in the energy value of the light source 1 that vary for each wavelength range. This reduces the impact of fluctuations in the energy value of light from the light source 1 on measurement accuracy.

[0041] Furthermore, because the baseline measurement is repeatedly performed at the wavelength change rate used in the actual measurement, the measurement conditions for the baseline measurement and the actual sample measurement can be matched. For example, in a method in which the wavelength change rate for the baseline measurement is slowed down to reduce the effect of temporal changes in the detected light intensity, the wavelength change rate for the actual measurement must be slowed down to match the measurement conditions for the slowed baseline measurement and the actual sample measurement. In this case, the actual measurement time increases. On the other hand, when the wavelength change rate for the baseline measurement is repeatedly performed at the wavelength change rate used in the actual measurement, as in this method, the wavelength change rate for the actual measurement can be maintained at the normal speed, and the actual measurement time does not increase. Furthermore, the reliability of the correction value using the baseline can be maintained high, and stable measurement results can be obtained even when measuring wavelengths with low light energy values.

[0042] In this embodiment, the spectrophotometer 100 is a double-beam spectrophotometer that irradiates the sample and reference material with the sample-side light beam 4 and the reference-side light beam 8 to analyze the sample, but the above-mentioned measurements can also be performed with a single-beam type that does not have a reference-side light beam or a ratio beam type that does not have a reference sample mounting section.

[0043] Furthermore, in the above measurement procedure, repeated baseline measurements are performed over the entire wavelength range of the actual measurement. However, it is also possible to selectively and repeatedly measure only a specific wavelength range with particularly low energy values. In this case, the instruction input unit 23 may be provided with an input function for the start wavelength Ws and end wavelength We of the baseline measurement, such as the item input fields Ds and De shown in FIG. 4, so that the specific wavelength range of the start wavelength Ws and end wavelength We for which the baseline measurement is repeated can be set. Only the baseline in the specific wavelength range set in this way is selectively and repeatedly measured a specified number of times N.

[0044] Specifically, the motor 32 shown in FIG. 1 is controlled to change the angle of the diffraction grating 31 while continuously changing the wavelength of the extracted light to measure the baseline. At this time, for measurements of a specific wavelength range, the scanning direction of that specific measurement wavelength range is reversed, and continuous reciprocating motion is performed multiple times. That is, the wavelength is gradually shortened from the start wavelength Ws to reach the end wavelength We, then the wavelength is returned to the start wavelength Ws, and the wavelength is gradually shortened again from the start wavelength Ws to reach the end wavelength We, and this operation is repeated according to the number of measurements N. Alternatively, the wavelength may be gradually shortened from the start wavelength Ws to reach the end wavelength We, and then the wavelength may be gradually lengthened to reach the start wavelength Ws, and this reciprocating motion may be repeated according to the number of measurements N.

[0045] In either case, the control unit 18 sets the scanning speed, i.e., the wavelength change speed, when repeatedly measuring the baseline in a specific measurement wavelength range for the number of measurements N to the same speed as the wavelength change speed (scanning speed) during actual measurement when measuring the measurement sample. This method makes it possible to efficiently and accurately determine the baseline for the entire wavelength range. Then, by correcting the spectral intensity distribution measured from the sample using the determined baseline, more accurate and stable measurement results can be obtained.

[0046] (Second embodiment) Next, a second embodiment will be described. In this embodiment, a wavelength range with a particularly low energy value is set as the specific wavelength range for repeating the above-mentioned baseline measurement based on the light energy distribution according to the light source 1.

[0047] 5 is a flowchart of the averaging process for baseline measurement according to the second embodiment. The user operates the instruction input unit 23 to set the measurement wavelength range for baseline measurement (S21). After inputting the measurement wavelength range for the baseline, the user operates the instruction input unit 23 to issue an instruction to start measuring the baseline.

[0048] Upon receiving the instruction to start measurement, the control unit 18 refers to the type information of the light source 1 stored in the storage unit and, based on the energy value distribution in the type information of the light source 1, sets the wavelength range where the energy value of the light source 1 is low as the specific wavelength range (S22). The type information of the light source 1 includes information on the distribution of the energy values ​​of the light emitted by that light source. For example, a threshold value that is the lower limit of the energy value is set in advance, and the wavelength range where the light energy value is equal to or less than the threshold is extracted from the type information of the light source 1 and set this as the specific wavelength range. Then, the control unit 18 starts baseline measurement of the measurement wavelength range (S23).

[0049] Fig. 6 is a graph showing an example of the distribution of energy values ​​in light source type information. As shown in Fig. 6, the energy value of light from light source 1 varies depending on the wavelength range. For example, in wavelength ranges Wa to Wb where the energy value is particularly low, the corrected measurement value fluctuates greatly depending on the magnitude of the baseline. Therefore, as described above, control unit 18 sets wavelength ranges Wa to Wb where the energy value is lower than a preset threshold T in the entire wavelength range of light source 1 as specific wavelength ranges.

[0050] The control unit 18 performs baseline measurement while changing the measurement wavelength, and when the measurement wavelength falls within the specific wavelength range Wa to Wb, repeats the baseline measurement within this specific wavelength range Wa to Wb the set number of measurements N according to the procedure described above (S24). At this time, the wavelength change speed is also set to the same speed as the wavelength change speed during actual measurement.

[0051] Then, after repeated measurements in the specific wavelength range Wa to Wb, the measurement of the entire measurement wavelength range is terminated (S25). The control unit 18 also performs an averaging process for each wavelength of the baseline in the specific wavelength range Wa to Wb (S26). In this averaging process, the control unit 18 calculates an average value for each wavelength by, for example, dividing the integrated value of measurement data obtained by repeatedly measuring the set specific wavelength range Wa to Wb multiple times by the number of measurements N. A baseline for the entire wavelength range is obtained from the average value in the specific wavelength range thus obtained and the measurement values ​​outside the specific wavelength range.

[0052] According to this embodiment, a wavelength range with a low energy value is set as a specific wavelength range based on the type information of the light source 1, and baseline measurements for this specific wavelength range are selectively performed repeatedly multiple times, thereby efficiently averaging the baseline. This reduces the impact of fluctuations in energy value on measurement accuracy, and prevents a decrease in measurement accuracy during actual measurement, especially when the energy value is low.

[0053] In this embodiment, the control unit 18 may monitor fluctuations in the measured baseline data or sample measurement data in real time, and when the fluctuations exceed a predetermined threshold, may notify the user by displaying guidance or the like on the display unit 22 to prompt the user to perform baseline averaging. In this way, the user can perform baseline averaging as needed based on the notification from the control unit 18 prompting the user to perform averaging. Alternatively, or in addition to the notification, baseline averaging may be automatically performed for wavelength ranges where fluctuations exceed a threshold.

[0054] In the averaging process by the control unit 18, outliers, which are clearly significantly fluctuating, may occur in the measured values ​​of the measured baseline. For example, if external light inadvertently enters the sample chamber 11 during measurement, an outlier, which is a significantly fluctuating measured value, may occur. In such cases, the control unit 18 may perform the averaging process while omitting the outlier. When such an outlier occurs, the user may be notified, for example, by displaying an error on the display unit 22. Furthermore, if an outlier occurs during the averaging process, a self-diagnosis process may be performed to investigate the cause of the outlier, or a notification may be issued to encourage the user to perform the self-diagnosis process.

[0055] Furthermore, a previously measured baseline may be used as the baseline for actual sample measurement, rather than measuring the baseline each time a measurement is performed. For example, if it is difficult to periodically introduce a baseline solution, a baseline measured using a standard test kit stored externally may be used. Information on these previously measured baselines may be supplied from another device via a network line by connecting the control unit 18 of the spectrophotometer 100 to a network line or via an appropriate storage medium.

[0056] The baseline measurement described above can be suitably applied from the viewpoint of rapid measurement, for example, in in-line measurement in which a sample flowing through a process pipe is directly measured, or in online measurement in which a representative sample is drawn from the process pipe into a bypass pipe and measured in real time.

[0057] The present invention is not limited to the above-described embodiments, and the present invention also contemplates the mutual combination of the various components of the embodiments, as well as modifications and applications by those skilled in the art based on the description in the specification and well-known techniques, and these modifications and applications are included in the scope of protection sought.

[0058] As described above, the present specification discloses the following: (1) a light source; a spectrometer that splits the light from the light source at a specified wavelength change rate; a detector that detects the sample-transmitted light beam that has been dispersed by the spectrometer and passed through the measurement sample for each wavelength; a control unit that determines a spectral intensity distribution of the light beam that has passed through the sample based on a measurement sample signal of the light beam that has passed through the sample output from the detector; Equipped with the control unit repeatedly measures a baseline indicating the background intensity of the measurement sample signal for each wavelength at the wavelength change rate during measurement of the measurement sample, and calculates an averaged baseline by averaging the multiple measured values ​​of the baseline for each wavelength; correcting the spectral intensity distribution using the averaged baseline; Spectrophotometer. This spectrophotometer performs baseline measurements multiple times and averages them, thereby appropriately averaging the baseline, which is affected by fluctuations in the light source energy value that vary across wavelength bands. This reduces the impact of fluctuations in the light source energy value on measurement accuracy. Furthermore, because the baseline is repeatedly measured at the wavelength change speed used in the actual measurement, the measurement conditions for the baseline measurement and the actual measurement of the spectral intensity distribution can be matched. This allows for efficient spectroscopic analysis without slowing down the wavelength change speed for the spectral intensity distribution, even when the baseline is measured at a slow wavelength change speed.

[0059] (2) an instruction input unit capable of inputting the number of measurements of the baseline; The spectrophotometer according to (1), wherein the control unit repeats the measurement of the baseline the input number of times. This spectrophotometer allows the user to set any number of baseline measurements, making it easy to achieve the required baseline accuracy and enabling stable measurement of the spectral intensity distribution with high accuracy.

[0060] (3) The control unit sets a wavelength range in which an energy value of light from the light source is equal to or less than a threshold as a specific wavelength range based on type information representing a type of the light source; The spectrophotometer according to (1) or (2), wherein the baseline measurement is repeated multiple times for the specific wavelength range, and the obtained multiple measurement values ​​are averaged for each wavelength to determine the averaged baseline. This spectrophotometer can efficiently average the baseline by, for example, setting a wavelength range with a low energy value as a specific wavelength range based on light source type information and performing measurements multiple times for this specific wavelength range, thereby suppressing the impact of fluctuations in energy value on measurement accuracy.

[0061] (4) The spectrophotometer according to any one of (1) to (3), wherein the control unit monitors fluctuations in at least one of the baseline measurement value and the measurement value of the measurement sample, and when the fluctuation range of the fluctuation exceeds a predetermined threshold, notifies the user to prompt averaging of the baseline in the wavelength range in which the fluctuation occurs. According to this spectrophotometer, the control unit can execute baseline averaging processing as necessary based on a notification urging baseline averaging.

[0062] (5) A beam splitter is provided to split the optical path of the light dispersed by the spectroscope into a sample-side beam to be guided to the measurement sample and a reference-side beam to be guided to a reference sample, the detector includes a sample-side detector that detects the sample-side light beam that has passed through the sample, and a reference-side detector that detects the reference-side light beam that has passed through the reference sample, The spectrophotometer according to any one of (1) to (4), wherein the control unit determines the spectral intensity distribution of the sample-side light beam based on a measurement sample signal of the sample-side light beam detected by the sample-side detector and a reference sample signal of the reference-side light beam detected by the reference-side detector. In this spectrophotometer, the optical path of the light dispersed by the spectroscope is split by a beam splitter into a sample-side beam and a reference-side beam, which are detected by a sample-side detector and a reference-side detector. This avoids the influence of fluctuations in the energy value of the light source over measurement time, suppresses baseline fluctuations over time, and thereby improves the measurement accuracy of the spectral intensity distribution.

[0063] (6) A spectrophotometric measurement method for spectrally separating light from a light source at a specified wavelength change rate, detecting a sample-transmitted beam of light for each wavelength that has passed through a measurement sample, and determining a spectral intensity distribution of the sample-transmitted beam of light based on the detected measurement sample signal of the sample-transmitted beam of light, repeating a baseline measurement indicating the background intensity of the measurement sample signal for each wavelength a plurality of times at the same wavelength change rate as the wavelength change rate when measuring the spectral intensity distribution; A plurality of measurements of the baselines repeatedly measured are averaged for each wavelength to obtain an average baseline; correcting the spectral intensity distribution using the averaged baseline; Spectrophotometric measurement method. According to this spectrophotometric measurement method, by repeatedly measuring the baseline multiple times and averaging the results, it is possible to appropriately average the baseline, which is affected by fluctuations in the light source energy value that vary across wavelength bands. This reduces the impact of fluctuations in the light source energy value on measurement accuracy. Furthermore, because the baseline is repeatedly measured at the wavelength change rate used in the actual measurement, it is possible to match the measurement conditions between the baseline measurement and the actual measurement of the spectral intensity distribution. This allows for efficient spectroscopic analysis without slowing down the wavelength change rate for the spectral intensity distribution, even when the baseline is measured at a slow wavelength change rate.

[0064] (7) A program for executing a spectrophotometric measurement procedure that disperses light from a light source at a specified wavelength change rate, detects a sample-passing beam for each wavelength that has passed through a measurement sample, and determines a spectral intensity distribution of the sample-passing beam based on the detected measurement sample signal of the sample-passing beam, On the computer, a step of repeatedly measuring a baseline indicating the background intensity of the measurement sample signal for each wavelength at the same wavelength change rate as the wavelength change rate when measuring the spectral intensity distribution; a step of obtaining an average baseline by averaging a plurality of measurements of the baseline repeatedly measured for each wavelength; correcting the spectral intensity distribution using the averaged baseline; A program to execute. This program allows for the baseline, which is affected by variations in the light source energy value that vary for each wavelength band, to be appropriately averaged by repeatedly measuring the baseline multiple times. This reduces the impact of variations in the light source energy value on measurement accuracy. Furthermore, because the baseline is repeatedly measured at the wavelength change speed used in the actual measurement, the measurement conditions for the baseline measurement and the actual measurement of the spectral intensity distribution can be matched. This allows for efficient spectroscopic analysis without slowing down the wavelength change speed of the spectral intensity distribution, even when the baseline is measured at a slow wavelength change speed. [Explanation of symbols]

[0065] 1 light source 2 Spectrometer 3 Beam Splitter 4. Sample side beam 5,6,7 Reflector 8 Reference beam 9. Sample placement area 10 Reference sample installation area 11 Sample chamber 14 Sample side detector (detector) 15 Reference detector (detector) 16 Sample side converter 17 Reference converter 18 Control Unit 20 Device Control Signal 21 Display signal 22 Display section 23 Instruction input section 31 Diffraction Grating 32 motor 100 spectrophotometer

Claims

1. A light source and a spectrometer that splits the light from the light source at a specified wavelength change rate; a detector that detects the sample-transmitted light beam that has been dispersed by the spectrometer and passed through the measurement sample for each wavelength; a control unit that determines a spectral intensity distribution of the light beam that has passed through the sample based on a measurement sample signal of the light beam that has passed through the sample output from the detector; Equipped with the control unit repeatedly measures a baseline indicating the background intensity of the measurement sample signal for each wavelength at the wavelength change rate during measurement of the measurement sample, and calculates an averaged baseline by averaging the multiple measured values ​​of the baseline for each wavelength; correcting the spectral intensity distribution using the averaged baseline; Spectrophotometer.

2. an instruction input unit capable of inputting the number of measurements of the baseline; The control unit repeats the baseline measurement the input number of times.

2. The spectrophotometer of claim 1.

3. the control unit sets a wavelength range in which an energy value of light from the light source is equal to or less than a threshold as a specific wavelength range based on type information representing a type of the light source; Repeating the measurement of the baseline multiple times for the specific wavelength range, and averaging the obtained multiple measurement values ​​for each wavelength to obtain the averaged baseline.

2. The spectrophotometer of claim 1.

4. The control unit monitors fluctuations in at least one of the baseline measurement value and the measurement value of the measurement sample, and when the fluctuation range of the fluctuation exceeds a predetermined threshold, notifies the user to prompt averaging of the baseline in the wavelength range in which the fluctuation occurs.

2. The spectrophotometer of claim 1.

5. a beam splitter that splits the optical path of the light dispersed by the spectroscope into a sample-side beam that is guided to the measurement sample and a reference-side beam that is guided to a reference sample; the detector includes a sample-side detector that detects the sample-side light beam that has passed through the sample, and a reference-side detector that detects the reference-side light beam that has passed through the reference sample, the control unit determines the spectral intensity distribution of the sample-side light beam based on a measurement sample signal of the sample-side light beam detected by the sample-side detector and a reference sample signal of the reference-side light beam detected by the reference-side detector.

5. A spectrophotometer according to any one of claims 1 to 4.

6. A spectrophotometric measurement method comprising: separating light from a light source at a specified wavelength change rate; detecting a sample-transmitted beam of light for each wavelength; and determining a spectral intensity distribution of the sample-transmitted beam of light based on a measurement sample signal of the detected sample-transmitted beam of light; repeating a baseline measurement indicating the background intensity of the measurement sample signal for each wavelength a plurality of times at the same wavelength change rate as the wavelength change rate when measuring the spectral intensity distribution; A plurality of measurements of the baselines repeatedly measured are averaged for each wavelength to obtain an average baseline; correcting the spectral intensity distribution using the averaged baseline; Spectrophotometric measurement method.

7. A program for executing a spectrophotometric measurement procedure that includes: separating light from a light source at a specified wavelength change rate; detecting a sample-passing beam for each wavelength that has passed through a measurement sample; and determining a spectral intensity distribution of the sample-passing beam based on a measurement sample signal of the detected sample-passing beam, On the computer, a step of repeatedly measuring a baseline indicating the background intensity of the measurement sample signal for each wavelength at the same wavelength change rate as the wavelength change rate when measuring the spectral intensity distribution; a step of obtaining an average baseline by averaging a plurality of measurements of the baseline repeatedly measured for each wavelength; correcting the spectral intensity distribution using the averaged baseline; A program to execute.

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