JP5596995B2 - Mercury atomic absorption spectrometer and mercury analysis system - Google Patents

Description

  The present invention relates to a mercury atomic absorption spectrometer and a mercury analysis system having two flow cells for flowing a measurement gas and measuring mercury in the measurement gas.

  Conventionally, mercury analyzers based on atomic absorption spectrometry have been widely used in environmental analysis and quality control analysis for many years. In the analysis of river water, etc., a device that uses the reduction vaporization method, in the analysis of the exhaust gas discharged from the chimney of the refuse incinerator, the device that measures the mercury in the exhaust gas online (Patent Document 1), in the analysis of the solid sample, Mercury atomic absorption spectrometer, etc. that heats and decomposes a sample in a sample container in a sample heating furnace while collecting air at a specified flow rate with an air pump, and collects and measures mercury generated from the sample with a mercury collection tube There is.

  There are a wide variety of samples analyzed in this way, and the mercury content of the samples is extensive. Therefore, an apparatus capable of measuring mercury in a sample in a wide dynamic range from a low concentration to a high concentration is desired.

  Therefore, as an apparatus for measuring mercury in a sample over a wide range from pg (picogram) to μg (microgram), there is a mercury atomic absorption spectrometer shown in FIG. This conventional first mercury atomic absorption spectrometer 500 includes a mercury lamp 1, a first flow cell 5 for measuring a low concentration, and a second optical path for measuring a high concentration that is shorter than the first flow cell 5. The flow cell 6 includes a first detector 507 that detects the light intensity of an analysis line that is emitted from the mercury lamp 1 and passes through the second flow cell 6 after passing through the first flow cell 5. The first flow cell 5 is a cylinder having an inner diameter of 10 mm × a length of 200 mm, and the second flow cell 6 is a cylinder having an inner diameter of 10 mm × a length of 10 mm.

  A cylindrical buffer tank 520 having an inner diameter of 10 mm and a length of 200 mm is provided between the first flow cell 5 and the second flow cell 6 as part of the gas flow path through which the measurement gas S flows. A time difference is provided between the time when the measurement gas arrives at the first flow cell 5 and the time when the measurement gas reaches the second flow cell 6, and the first detector at the time when the measurement gas S passes through the first flow cell 5. The peak profile measured by the first flow cell 5 and the second flow cell by temporally separating the light intensity signal detected by the photoelectric tube) 507 and the light intensity signal detected at the time of passing through the second flow cell 6. The peak profile measured by 6 is separated. Thus, the peak profile by the first flow cell 5 for low concentration measurement and the peak profile by the second flow cell 6 for high concentration measurement are separated and measured in a wide dynamic range.

  A light beam emitted from the mercury lamp 1 is collected by the lens 2, enters a beam splitter 503 that is a half mirror of a quartz plate, passes through the beam splitter 503, and is a first flow cell for detecting the amount of mercury. 5 is split into measurement light 521 that is incident on 5 and reference light 522 that is reflected by the beam splitter 503 and incident on the second detector 509. The reference light 522 is light emitted from the mercury lamp 1 for so-called double beam photometry, that is, based on a ratio with the light intensity measured by the first detector 507 by monitoring the light intensity fluctuation of the mercury lamp 1. Used to compensate for intensity fluctuations.

  The operation of this mercury atomic absorption spectrometer 500 will be described below. The measurement gas S first passes through the first flow cell 5 and is carried to the second flow cell 6 via the buffer tank 520. While the measurement gas S passes through the first flow cell 5, the light intensity that has passed through the first flow cell 5 is detected by the first detector 507 as the first signal, and the measurement gas whose flow has been delayed through the buffer tank 520 is detected. The light intensity when S passes through the second flow cell 6 is also detected by the first detector 507 as the second signal. In addition, the reference light 522 is detected by the second detector 509 as a third signal. In the low concentration region, the ratio of the first signal obtained by the first flow cell 5 having a longer optical path and higher sensitivity and the third signal of the reference light 522 is processed by a signal processing circuit (not shown), and the high concentration is obtained. In the region, even if the ratio between the first signal and the third signal is saturated, the ratio between the second signal and the third signal of the second flow cell 6 having a shorter optical path and lower sensitivity is the signal processing. The dynamic range is expanded by being processed by the circuit.

  Further, there is an apparatus described in Non-Patent Document 1 as a conventional second mercury atomic absorption spectrometer. As shown in FIG. 19, the mercury atomic absorption analyzer 600 includes a buffer tank 620 between the first flow cell 5 and the second flow cell 6 in the same manner as the mercury atomic absorption analyzer 500 described above. Then, the third flow cell 610 having a longer optical path than the first flow cell 5 is provided to further expand the dynamic range. In this apparatus 600, the analysis line of the mercury lamp 1 is incident on the first flow cell 5 and the third flow cell 610 from the two light emission windows 601 and 602 of the mercury lamp 1 and passes through the first and second flow cells. The intensity is detected by the first detector 607, and the intensity of the light beam that has passed through the third flow cell is detected by the second detector 608. The mercury atomic absorption spectrometer 600 is not configured to monitor the reference light by dividing the analysis line radiated from the same portion of the mercury lamp 1 into measurement light and reference light. It is not possible to compensate for variations in light intensity.

JP 2001-33434 A

“NEW PRODUCT RELEASE Milestone Tri-cell DMA-80” (Italy), MILESTONE SRL

  FIG. 17 shows peak profiles obtained by measuring a measurement gas containing 20 ng (nanogram), 500 ng, and 1000 ng of mercury with the conventional first mercury atomic absorption spectrometer 500. According to this peak profile, the peak profile of the first flow cell and the peak profile of the second flow cell can be separated from 20 to 500 ng, but the peak profile of the first flow cell and the peak profile of the second flow cell overlap at 1000 ng. Each peak profile is not separated. In mercury atomic absorption spectrometry, the integrated value of peak profiles is often used as the signal intensity. However, if peak profiles overlap, it becomes impossible to integrate each peak profile individually. Furthermore, when measuring a medium concentration measurement gas, as shown in FIG. 18, tailing of the peak of the first flow cell increases the apparent peak of the second flow cell, which may make it difficult to accurately measure the amount of mercury. is there. Therefore, there is a problem that accurate measurement cannot be performed with a wide dynamic range. In addition, the provision of the buffer tank increases the measurement time and the size of the entire apparatus. A similar problem occurs in the conventional second mercury atomic absorption spectrometer 600 having three flow cells.

  The present invention has been made in view of the above-described conventional problems, and it is an object of the present invention to provide a mercury atomic absorption spectrometer that can improve the accuracy and precision of mercury analysis in a wide dynamic range measurement, and is compact and can shorten the measurement time. And

  In order to achieve the above object, a mercury atomic absorption spectrometer of the present invention divides a mercury lamp that emits a ray of mercury analysis line and a ray emitted from the mercury lamp into a first beam and a second beam. A first beam splitter; a second beam splitter for splitting the second beam into a third beam and a fourth beam; a first flow cell through which the first beam and measurement gas pass; and a first flow cell through which the first flow cell has passed. A first detector on the measurement side that detects the light intensity of one beam and a measurement gas flow path together with the first flow cell, are arranged downstream of the first flow cell, and are different from the optical path length of the first flow cell. A second flow cell having an optical path length through which the third beam and the measurement gas pass, and a second detection on the measurement side for detecting the light intensity of the third beam that has passed through the second flow cell A detector on the reference side that detects the light intensity of the fourth beam, a ratio between the light intensity detected by the first detector on the measurement side and the light intensity detected by the detector on the reference side, and Based on the ratio of the light intensity detected by the second detector on the measurement side and the light intensity detected by the detector on the reference side, the mercury in the measurement gas flowed into the measurement gas channel is quantified. And a quantification means.

  According to the apparatus of the present invention, the measurement of the first flow cell and the measurement of the second flow cell are performed in a compact configuration not including a buffer tank between the first flow cell for low concentration measurement and the second flow cell for high concentration measurement. The measurement time is shortened by simultaneously performing the detection with a detector corresponding to the above, and the overlap between the peak due to the first flow cell and the peak due to the second flow cell is eliminated. Further, both the first flow cell and the second flow cell are subjected to double beam photometry. As a result, the accuracy and accuracy of mercury analysis can be improved in a wide dynamic range measurement.

  In the mercury atomic absorption spectrometer of the present invention, the split ratio of the first beam and the second beam in the first beam splitter is 1: 1, and the third beam in the second beam splitter and the The division ratio with the fourth beam is preferably 1: 1. With this configuration, the first and third beams, which are measurement light, and the fourth beam, which is the reference light, have similar light intensities, and stable double beam photometry can be performed. Accuracy and accuracy of mercury analysis Can be further improved.

  The mercury analysis system of the present invention includes the mercury atomic absorption spectrometer of the present invention and a mercury vaporizer that vaporizes mercury in a sample and introduces it into the mercury atomic absorption spectrometer as a measurement gas.

  According to the mercury analysis system of the present invention, since the mercury atomic absorption analyzer of the present invention is provided, the same operations and effects as the mercury atomic absorption analyzer of the present invention can be achieved.

It is a schematic block diagram of the mercury analysis system which is an embodiment of the present invention. It is a schematic block diagram of the mercury atomic absorption spectrometer of the system. It is a top view of the half mirror which is a beam splitter of the apparatus. It is a top view of the half mirror of the modification of the same apparatus. It is a top view of the half mirror of the further modification of the apparatus. It is the profile of the measurement signal measured with the same apparatus. It is an expansion profile of the measurement signal measured with the same apparatus. It is a figure which shows the range of the amount of mercury which can be measured with the same apparatus. It is a figure which shows the calibration curve measured with the 1st flow cell of the same apparatus. It is the peak profile measured with the 1st flow cell of the device. It is a figure which shows the primary type | formula analytical curve measured with the same apparatus. It is a figure which shows the tertiary type | mold calibration curve measured with the same apparatus. It is a figure which shows the base line at the time of using an undeposited quartz board as a beam splitter with the same apparatus. It is a figure which shows the base line at the time of using another beam splitter with the same apparatus. It is a side view of the modification of the beam splitter of the same apparatus. It is a schematic block diagram of the conventional mercury atomic absorption spectrometer. It is the profile of the measurement signal measured with the same apparatus. It is the profile of the other measurement signal measured with the same apparatus. It is a schematic block diagram of another conventional mercury atomic absorption spectrometer.

  Hereinafter, a mercury analysis system according to an embodiment of the present invention shown in FIG. 1 will be described. The mercury analysis system 120 includes a mercury vaporization apparatus 200 that vaporizes mercury in a sample to obtain a measurement gas S, and a mercury atomic absorption analysis apparatus 100 that introduces and measures the measurement gas S vaporized by the mercury vaporization apparatus 200. It consists of

The mercury vaporizer 200 is, for example, activated carbon C that collects mercury in flue exhaust gas as a sample.
The thermal decomposition unit 210 that generates mercury gas by thermally decomposing the gas, the dehumidifier 202 that removes moisture carried together with the carrier gas G that carries the generated mercury gas, and the mercury gas generated by the thermal decomposition unit 210 Of the mercury gas collection unit 204 for collecting the gas, the heating vaporization unit 205 for heating the mercury collection unit 204 to generate mercury gas, and the carrier gas G from the sample inlet 213 of the thermal decomposition unit 210 to the dehumidifier 202. A first pipe 216 that is a flow path, a second pipe 203 from the dehumidifier 202 to the mercury collecting unit 204, and a carrier gas control means 206 that controls the flow rate of the carrier gas G are provided.

  The thermal decomposition unit 210 contains activated carbon C that collects mercury in the sample, for example, a sample vessel 212 made of ceramic, a sample heating furnace 211 that heats activated carbon C contained in the sample vessel 212, and activated carbon C. Collects sulfur and halogen produced by heating the activated carbon C by the sample heating furnace 211, and the catalyst furnace 214 for reducing divalent mercury produced by being heated by the sample heating furnace 211 to metallic mercury And a halogen removal furnace 215 for removal.

  Examples of the filler of the mercury collecting unit 204 include a granular material such as gold or silver that reacts with metallic mercury to produce an amalgam, a wool-like fine wire, or a porous carrier whose surface is coated with gold or silver. Is used. The heating vaporization unit 205 houses a mercury collection unit 204 that collects the mercury generated by the thermal decomposition unit 210 in a heating furnace, and heats the mercury collection unit 204 to collect the collected mercury. Vaporize. The carrier gas control means 206 includes a pump 261 for sucking the carrier gas G supplied from the carrier gas supply means (not shown) from the sample inlet 213 of the sample heating furnace 211 as an introduction part of the carrier gas G, and the carrier A flow meter 262 for controlling the flow rate of the gas G.

  The mercury vaporization apparatus 200 is not limited to the above-described apparatus, and may be an apparatus that generates a measurement gas by heating a solid or liquid sample collected in a sample container in a heating furnace to vaporize mercury in the sample. .

  The mercury vaporizer 200 may be a reductive vaporizer. The reducing vaporizer generates a measurement gas by reducing and vaporizing mercury in a liquid sample by introducing a reducing agent into the liquid sample and bubbling with air.

  As shown in FIG. 2, the mercury atomic absorption spectrometer 100 includes a mercury lamp 1 that emits ultraviolet rays having a wavelength of 253.7 nm, which is a mercury analysis line, and ultraviolet rays 20 that are emitted from the mercury lamp 1 that has passed through the lens 2. The first beam splitter 3, which is a half mirror that splits the first beam 21 and the second beam 22, the first flow cell 5 through which the first beam 21 passes, and the light intensity of the first beam 21 that has passed through the first flow cell 5. The first detector 7 on the measurement side which is a phototube for detecting the second beam, the second beam splitter 4 which is a half mirror for dividing the second beam 22 into the third beam 23 and the fourth beam 24, and the optical path of the first flow cell 5 A second flow cell 6 having a shorter optical path, a second detector 8 on the measurement side that is a photoelectric tube that detects the light intensity of the third beam 23 that has passed through the second flow cell 6, and a fourth bee. And a detector 9 of the reference side is a phototube for detecting a light intensity of 24. The second flow cell 6 forms a measurement gas flow path 10 together with the first flow cell 5 and is arranged on the downstream side of the first flow cell 5.

  Further, the mercury atomic absorption spectrometer 100 detects the light intensity detected by the first detector 7 on the measurement side and the detector 9 on the reference side when the measurement gas S passes through the measurement gas channel 10. Based on the ratio 31 to the light intensity and the ratio 32 of the light intensity detected by the second detector 8 on the measurement side and the light intensity detected by the detector 9 on the reference side, the flow is made to flow into the measurement gas channel 10. A quantification means 15 for quantifying mercury in the measured gas S is provided. Between each detector 7, 8, 9 and the quantification means 15, the first, second and third current-voltage converters 11, 12, 13 corresponding to each detector, the signal processing circuit 14, and It has.

  The mercury lamp 1 is a mercury lamp or a mercury hollow cathode lamp usually used for atomic absorption analysis. The first and second flow cells 5 and 6 have a cylindrical flow cell body provided with an inlet and an outlet for mercury vapor, which is a measurement gas S, into the flow cell, and analytical lines are provided at both ends of the cylinder of the flow cell body. It has an incident window and an exit window made of, for example, fused silica, to which an ultraviolet ray having a wavelength of 253.7 nm is incident. The first flow cell 5 is for low concentration measurement, and the second flow cell 6 has a shorter optical path than the first flow cell 5 and is for high concentration measurement. The ratio of the optical path lengths of the first flow cell 5 and the second flow cell 6 is preferably 50: 1 to 300: 1, and more preferably 150: 1 to 250: 1. For example, the first flow cell 5 is a cylinder having an inner diameter of 100 mm and an optical path length of 200 mm, and the second flow cell 6 is a cylinder having an inner diameter of 100 mm and an optical path length of 1 mm.

  The first beam splitter 3 divides the light emitted from the mercury lamp 1 into a first beam 21 that is transmitted light and a second beam 22 that is reflected light at a ratio of 1: 1, and the second beam splitter 4. Divides the second beam 22 into a third beam 23 that is transmitted light and a fourth beam 24 that is reflected light at a ratio of 1: 1. The first and second beam splitters 3 and 4 are the same half mirror, for example, a quartz plate having a thickness of 1 mm with aluminum deposited in a stripe shape on the surface as shown in FIG. In addition to the stripe shape shown in FIG. 3, it may be a half mirror with aluminum deposited in a lattice shape shown in FIG. 4 or a polka dot shape shown in FIG. 5, or a half mirror coated on one side with a dielectric multilayer film.

  Next, the operation of the mercury analysis system of this embodiment will be described. When the mercury atomic absorption spectrometer 100 of FIG. 1 is turned on, the mercury lamp 1 is turned on, the first beam 21 is irradiated to the incident window of the first flow cell 5, and the first flow cell 5 is transmitted and emitted from the emission window. The light intensity of the first beam 21 is detected by the first detector 7, the generated current is converted into a voltage by the first current-voltage converter 11 and output as a first signal, and the first signal is signal processed. Input to the circuit 14. At the same time, the incident beam of the second flow cell 6 is irradiated with the third beam 23, the light intensity of the third beam 23 transmitted through the second flow cell 6 and emitted from the emission window is detected by the second detector 12, and the generated current Is converted into a voltage by the second current-voltage converter 12 and output as a second signal, and the second signal is input to the signal processing circuit 14. On the other hand, the light intensity of the fourth beam 24 is detected by the third detector 9, the generated current is converted into a voltage by the third current-voltage converter 13 and output as a third signal, and the third signal is a signal. The signal is input to the processing circuit 14, and the signal processing circuit 14 converts the first signal to the third signal to a ratio 31 and the second signal to the third signal to a ratio 32 and inputs the signals to the quantification means 15.

  In FIG. 1, activated carbon C that collects mercury in a sample is accommodated in a sample container 212, and the sample container 212 is inserted into the heating vaporizer 200. When the activated carbon C is thermally decomposed by the thermal decomposition unit 210 of the heating vaporizer 200, the collected mercury is gasified and collected in the mercury collecting unit 204. Mercury atomic absorption analysis of FIG. 2 using the carrier gas G adjusted to a flow rate of 0.2 l / min as the measurement gas S, the mercury gas evaporated from the collection unit 204 being heated by the heating vaporization unit 205. The measurement gas S is introduced into the measurement gas channel 10 of the apparatus 100, and the measurement gas S flows in the order of the first flow cell 5 and the second flow cell 6. When the measurement gas S flows into the first and second flow cells 5 and 6, the ultraviolet rays of the analysis lines passing through the first and second flow cells 5 and 6 are absorbed by the mercury in the measurement gas S. Light intensity decreases. Each signal is processed by the signal processing circuit 14, and the first signal / third signal 31 and the second signal / third signal 32 are generally profiled as the peak of the first flow cell and the peak of the second flow cell in FIG. As shown, each signal intensity increases to reach a maximum value, and then decreases. When the measurement gas S is introduced into the measurement gas flow path 10, the measurement is started and the signal intensity is integrated until the fall of the signal intensity. The obtained integrated value is input to the quantification means 15 to quantify mercury in the sample.

  FIG. 7 shows peak profiles of the first flow cell 5 (cell length 200 mm) and the second flow cell 6 (cell length 1 mm) when 5 ng of mercury is measured using the mercury atomic absorption spectrometer 100 of the present embodiment. . In FIG. 7, since the scale is enlarged and displayed in order to clearly show the peak of the second flow cell 6, the upper part of the peak profile of the first flow cell 5 is cut.

  The following table shows the amount of mercury detected when 5 ng of mercury was measured 5 times in the second flow cell and the degree of variation in the measured value (coefficient of variation). The CV value is 1.50%, and an accurate measurement result is obtained.

  FIG. 8 shows a measurable range of the mercury amount by the mercury atomic absorption spectrometer 100. The calibration curve linearity was secured by the first flow cell 5 from 2 pg to 10 ng and by the second flow cell 6 from 5 ng to 2000 ng (2 μg), and the calibration curve linearity could be secured within a range of almost 7 digits. By using a cubic calibration curve, it is possible to measure up to an 8-digit range. The area from 5 ng to 10 ng can be measured by both the first and second flow cells 5 and 6.

  9 to 12 show measurement results obtained by the mercury atomic absorption spectrometer 100. FIG. FIG. 9 shows a calibration curve from 0 to 10 ng of mercury obtained by the first flow cell 5. FIG. 10 shows peak profiles measured in the first flow cell 5 for mercury amounts of 2, 4, 6, 10 ng. FIG. 11 shows a calibration curve from 0 to 2000 ng obtained by the second flow cell 6. FIG. 12 shows a calibration curve from 0 to 25000 ng obtained by the second flow cell 6. In the region of 2000 ng or more, a mercury amount of up to 25000 ng can be measured by using a calibration curve approximated to a cubic equation. In the calibration curves shown in FIGS. 9, 11 and 12, the horizontal axis represents the mercury amount, and the vertical axis represents the value obtained by time integration of the peak profile.

  As described above, the mercury atomic absorption spectrometer 100 of the present embodiment has a linearity of a calibration curve from 2 pg to 2000 ng, and can measure a wide range of mercury up to 25000 ng by using a calibration curve of a cubic equation. It is possible, and the mercury atomic absorption signals of the first and second flow cells are measured independently, so that the integral value of each profile can be obtained accurately and individually. Further, since it is not necessary to use a buffer tank as in the prior art, the optical system can be made compact, the peak profiles of the first and second flow cells can be measured simultaneously, and the measurement time can be shortened. .

  Next, in the mercury atomic absorption spectrometer 100 of the present embodiment, the results of experiments on the noise level of measurement data due to the difference in the ratio of transmitted light and reflected light of the first beam splitter 3 and the second beam splitter 4 will be described. What is important in the mercury atomic absorption spectrometer 100 is that the measurement upper limit of the first flow cell 3 for low concentration measurement and the measurement lower limit of the second flow cell 4 for high concentration measurement overlap. It is required that the measurement accuracy in the vicinity of 5 ng in the two flow cell 4 is sufficiently obtained. The lower detection limit of measurement depends on the noise level of the baseline of the absorbance profile, and the smaller the noise level, the lower the concentration can be measured. FIG. 13 shows a baseline profile of the second flow cell 4 when an undeposited quartz plate having a thickness of 1 mm is used as the first and second beam splitters 3 and 4. As shown in FIG. 13, the noise level is Abs. (Absorbance) is about 0.0004. The signal strength of 5 ng in the second flow cell is Abs. In this state, it is not possible to obtain good accuracy by measuring 5 ng, and it is not possible to obtain good accuracy even in continuous measurement in the low concentration range and the high concentration range.

  The reason why the noise is increased when using an undeposited quartz plate is that the transmittance of ultraviolet rays, which is an analysis line, is high and the reflectance is low, so that the second is greater than the amount of light incident on the first flow cell 5. This is probably because the amount of light incident on the flow cell 6 was too low. Specifically, the photocurrent flowing through the first current-voltage converter 11 on the first flow cell 5 side when mercury gas is not flowing is about 200 nA, whereas the photocurrent flowing on the first flow cell 5 side is about 200 nA. The current flowing through the 2-current-voltage converter 12 was 1/50 of 4 nA. This is because a current-voltage converter using an operational amplifier or the like has a characteristic that when the signal current becomes small, it is easily affected by electromagnetic noise from the outside, so that the amount of light transmitted through the second flow cell 6 is small. This is because the baseline noise increases when the photocurrent flowing through the two-current-voltage converter 12 is small.

  As means for increasing the amount of light incident on the second detector 8, aluminum is vapor-deposited in stripes on one side of a quartz plate as shown in FIG. 3, and the area of the transmissive part (the part without vapor deposition) and the reflective part (deposited). A half mirror having an area of about 1: 1 was used for the first and second beam splitters. By using a half mirror with improved reflectivity as a beam splitter, the amount of light incident on the second flow cell 6 could be increased about 10 times. The half mirror in which the area of the transmissive part and the area of the reflective part are about 1: 1 is divided into a first beam and a second beam at a ratio of 1: 1, and a third beam and a fourth beam are 1: 1. Divide by the ratio. FIG. 14 shows a baseline profile of the mercury atomic absorption spectrometer 100 using a half mirror with a split ratio of 1: 1 as the first and second beam splitters. It can be seen that there is a significant improvement compared to the noise level in FIG. In this way, by setting the beam splitting ratio of the transmitted light and reflected light of the beam splitter to 1: 1, the noise and stability of the baseline can be greatly improved compared to the undeposited quartz plate, and the low concentration The measurement upper limit of the range and the measurement lower limit of the high concentration range overlap each other, and measurement can be performed with high accuracy.

  As described in the present embodiment, the mercury atomic absorption spectrometer 100 of the present invention has a compact configuration that does not include a buffer tank between the first flow cell 5 for low concentration measurement and the second flow cell 6 for high concentration measurement. The measurement of the first flow cell 5 and the measurement of the second flow cell 6 are simultaneously performed by the corresponding detectors 7 and 8, thereby reducing the measurement time, and the peak due to the first flow cell 5 and the peak due to the second flow cell 6 In addition, both the first flow cell 5 and the second flow cell 6 compensate for fluctuations in the intensity of light emitted from the mercury lamp 1 by double beam photometry, improving the accuracy and accuracy of mercury analysis in a wide dynamic range measurement. Can be made.

  In the embodiment of the present invention, the half mirror is used as the beam splitter. However, the present invention is not limited to the half mirror, but a wedge type that divides the light beam 20 of the mercury lamp into the first beam 21 and the second beam 22 as shown in FIG. Or a rotating sector (not shown) having a transmission part formed by a through hole and a reflection part formed by a mirror alternately along the circumference. Good. The first, second and third detectors may be photomultiplier tubes capable of detecting a mercury analysis line of 253.7 nm. In the embodiment of the present invention, the first flow cell 5 is for low concentration measurement whose optical path is longer than that of the second flow cell 6, and the second flow cell 6 is for high concentration measurement whose optical path is shorter than that of the first flow cell 5. Or vice versa.

DESCRIPTION OF SYMBOLS 1 Mercury lamp 3 1st beam splitter 4 2nd beam splitter 5 1st flow cell 6 2nd flow cell 7 1st detector 8 2nd detector 9 Reference side detector 10 Measurement gas flow path 15 Quantification means 21 1st beam 22 Second beam 23 Third beam 24 Fourth beam 100 Mercury atomic absorption analyzer 120 Mercury analysis system 200 Mercury vaporizer

Claims (3)

A mercury lamp that emits rays of mercury analysis lines;
A first beam splitter that splits a light beam emitted from the mercury lamp into a first beam and a second beam;
A second beam splitter for splitting the second beam into a third beam and a fourth beam;
A first flow cell through which the first beam and measurement gas pass;
A first detector on the measurement side that detects the light intensity of the first beam that has passed through the first flow cell;
A measurement gas flow path is formed together with the first flow cell, and is disposed downstream of the first flow cell. Two flow cells;
A second detector on the measurement side for detecting the light intensity of the third beam that has passed through the second flow cell;
A reference detector for detecting the light intensity of the fourth beam;
The ratio between the light intensity detected by the first detector on the measurement side and the light intensity detected by the reference detector, and the light intensity detected by the second detector on the measurement side and the reference side Based on a ratio with the light intensity detected by the detector, a quantitative means for quantifying mercury in the measurement gas passed through the measurement gas flow path,
Bei to give a,
A mercury atomic absorption analyzer that simultaneously and independently measures a peak profile, which is a mercury atomic absorption signal, in the first flow cell and the second flow cell . 2. The mercury atomic absorption spectrometer according to claim 1, wherein a split ratio of the first beam and the second beam in the first beam splitter is 1: 1, and the third beam in the second beam splitter is 3rd. A mercury atomic absorption spectrometer in which the split ratio of the beam and the fourth beam is 1: 1. A mercury atomic absorption spectrometer according to claim 1 or 2,
A mercury vaporizer that vaporizes mercury in the sample and introduces it into the mercury atomic absorption spectrometer as a measurement gas;
Mercury analysis system equipped with.

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