CN210198946U - Atomic absorption spectrophotometer - Google Patents

Abstract

The utility model relates to an analytical instrument field, concretely relates to atomic absorption spectrophotometer, include: a light source; a flame atomizer comprising an atomizing device and a combustion device, the combustion device being configured to atomize the atomized sample into an atomic vapor by combustion; a light splitting device; a light beam guide device arranged between the light source and the light splitting device; the light beam guiding device includes: a first mirror and a second mirror arranged to face the atomic vapor and to be opposite to each other; and a third mirror and a fourth mirror; the following paths of the light beam are formed by means of the four mirrors: the light beam from the light source passes through the atomic vapor via reflection by the third mirror, then passes back and forth through the atomic vapor once more by successive reflections on the first mirror and the second mirror, and then impinges on the fourth mirror. Because the light beam can pass through the atomic steam in the flame for three times, the detection limit of the atomic absorption spectrophotometer can be expanded, and the detection precision is improved.

Description

Atomic absorption spectrophotometer

Technical Field

The utility model relates to an analytical instrument for among analysis sample heavy metal element mainly is an atomic absorption spectrophotometer.

Background

The atomic absorption spectrometry is an analysis method for determining the content of an element to be detected in a sample according to the absorption of ground state atoms on characteristic wavelength light, and is called atomic absorption analysis for short. Instruments used for atomic absorption spectroscopy are called atomic absorption spectrophotometers or atomic absorption spectrometers. Atomic absorption spectrophotometers (also known as atomic absorption spectrometers) can perform elemental analysis of metals based on the effect of atomic vapors in the ground state of a substance on the absorption of characteristic radiation. Generally, atomic absorption spectrophotometers are capable of sensitive and reliable determination of trace amounts or trace elements.

Atomic absorption spectrophotometers have atomizers which are largely composed of two different types, namely, flame atomizers and electric heat atomizers. The flame used in flame atomizers is of various types, and currently, an air-acetylene flame is commonly used. The electric heating atomizer is generally applied to a graphite furnace atomizer. Up to now, the current atomic absorption spectrophotometers are generally an absorption spectrophotometer with a flame atomizer and an atomic absorption spectrophotometer with a graphite furnace.

As shown in fig. 1, the atomic absorption spectrophotometer in the prior art mainly comprises a light source, an atomizer, a monochromator, a detection system, a display system, and the like. However, since the physical range of the atomic vapor burned in the atomizer is limited, the light beam emitted from the light source passes through the atomic vapor only once and reaches the subsequent monochromator. This can be problematic for high sensitivity demanding detection applications, since the sensitivity or measurement accuracy of atomic absorption spectrophotometers is directly related to the extent of absorption of characteristic wavelengths of light by atomic vapors.

For this reason, there is a need in the field of sample analysis and detection for improving the detection limit of atomic absorption spectrophotometers, that is, for an atomic absorption spectrophotometer capable of more accurately detecting the content (or concentration) of a specific element (mainly, heavy metal element) contained in a sample solution without adding expensive auxiliary instruments.

SUMMERY OF THE UTILITY MODEL

The utility model provides an atomic absorption spectrophotometer, include: a light source emitting a light beam having a characteristic wavelength spectrum line that is absorbed by an element to be measured in a sample; a flame atomizer comprising an atomizing device configured to atomize a sample and a combustion device configured to atomize the atomized sample into an atomic vapor by combustion; a light splitting device for separating the characteristic wavelength spectral line of the element to be measured from other spectral lines in the light beam; a light beam guiding device arranged between the light source and the light splitting device for guiding the light beam from the light source through the atomic vapor and to the light splitting device; wherein the beam guiding device comprises: a first mirror and a second mirror arranged to face the atomic vapor and to be opposite to each other, the first mirror being arranged on a side of the atomic vapor facing the light splitting device, and the second mirror being arranged on the other side of the atomic vapor facing the light source; and a third mirror and a fourth mirror, the third mirror being disposed between the light source and the atomic vapor, and the fourth mirror being disposed between the atomic vapor and the light-splitting device; forming the following optical path of the light beam by means of the first mirror, the second mirror, the third mirror and the fourth mirror: the light beam from the light source passes through the atomic vapor by reflection on the third mirror, then passes through the atomic vapor again and again by successive reflection on the first mirror and the second mirror once, and then impinges on the fourth mirror to be directed toward the light splitting device by reflection on the fourth mirror.

Because the light beam can penetrate through the atomic steam in the flame for three times, compared with the prior art in which the light beam only penetrates through the flame once, the light energy absorbed by the element to be detected of the sample in the light beam can be remarkably increased, so that the variation of the electric signal value (the electric signal value can be converted into an absorbance value through software design and then converted into a concentration value of the element to be detected) acquired in a detection device or other controllers subsequently is more remarkable, the detection limit of the atomic absorption spectrophotometer is expanded, and the detection precision is improved. Meanwhile, by means of the arrangement of the first reflecting mirror, the second reflecting mirror and the third reflecting mirror, the light beam only passes through atomic steam three times in the whole light path of the light beam, so that the light intensity loss caused by the reflection of the light beam on the reflecting mirrors can be greatly reduced, and the detection efficiency of the whole atomic absorption spectrophotometer is maximized.

Preferably, the first mirror and the second mirror are both plane mirrors. Alternatively or additionally, the third mirror and the fourth mirror are both planar mirrors.

Compared with a curved reflector, the plane reflector has the advantages of simpler structure, lower cost and more convenient arrangement in the aspect of angle orientation.

In some embodiments, at least one of the third mirror and the fourth mirror may, for example, be arranged in a perpendicular orientation to both the first mirror and the second mirror in order to achieve a reasonable orientation relationship between the third and first mirrors and between the fourth and second mirrors that meets a desired reflection angle.

Advantageously, the orientation of the first mirror and/or the second mirror is adjustable. Alternatively or additionally, the orientation of the third mirror and/or the fourth mirror is adjustable.

By means of the reflecting mirror with adjustable orientation, the purposes of flexibly adjusting the reflecting angle and the spatial position of the reflecting mirror according to the position of the atomic vapor can be achieved.

It is particularly preferred that the first mirror and the second mirror can be arranged at the same height with respect to the atomic vapor and offset from each other. The arrangement at the same height allows a compact beam directing arrangement to be achieved, while the offset front to back allows the actual path of the beam through the atomic vapour to be optimised, for example to avoid interference between the two mirrors.

In some examples, the first mirror may be tilted with respect to a vertical direction, and the second mirror may extend in the vertical direction. In other words, the first mirror and the second mirror may not be disposed parallel to each other.

Thereby, the positions and angles of the third and fourth mirrors in the beam guiding apparatus can be set more flexibly. In addition, the optical path through the atomic vapor may also be adjusted for the morphology of the atomic vapor in combustion, enabling adjustments to be made to the specific region through the atomic vapor in the flame (e.g., determining whether to pass it at its maximum diameter.

In particular, the atomic absorption spectrophotometer may further include a detection device configured to convert a light beam split by the splitting device into an electric signal to learn the concentration of the element to be measured of the sample. Therefore, the content of the element to be detected can be conveniently obtained according to the empirical curve.

For example, the light source may be a hollow cathode lamp or an electrodeless discharge lamp. In particular, hollow cathode lamps emit a sharp spectral line which is narrower than the width of the absorption line, and are high and stable in intensity, low in background and noise, and long in service life.

Drawings

With reference to the above purposes, the technical features of the invention are hereinafter clearly described, and the advantages thereof are apparent from the following detailed description with reference to the accompanying drawings, which illustrate, by way of example, a preferred embodiment of the invention, without limiting its scope. It should also be noted that the figures referred to are not all drawn to scale but may be exaggerated to illustrate various aspects of the present invention, and in this regard, the figures should not be construed as limiting.

FIG. 1 shows a schematic diagram of an atomic absorption spectrophotometer according to the prior art; and

fig. 2 shows a schematic principle diagram of an embodiment of an atomic absorption spectrophotometer according to the present invention.

List of reference numerals:

a 100 atomic absorption spectrophotometer;

10 light source;

20 a flame atomizer;

30 a light splitting device;

40 a detection device;

52 a first mirror;

54 a second mirror;

56 a third mirror;

58 a fourth mirror;

200 atoms of steam.

Detailed Description

The operating principle of the atomic absorption spectrophotometer 100 according to some embodiments of the present invention is as follows: the substance to be analyzed (hereinafter also referred to as "sample") is converted into a solution (also referred to as "sample solution") in an appropriate manner, and the solution is introduced into the atomizer. The solution may be atomized within the atomizer, but may also be atomized before entering the atomizer. The measured elements in the sample are then atomized in an atomizer to a ground state atomic vapor. When a characteristic line emitted from a light source and having the same absorption wavelength as that of an element to be measured passes through the vapor of ground-state atoms, light energy is attenuated by the absorption of the ground-state atoms, and the degree of attenuation (i.e., absorbance) has a predetermined relationship with the number of ground-state atoms (element concentration) under certain conditions, for example, a relationship complying with lambert-beer's law. The spectral lines absorbed by the ground state atoms are split by the splitting system and then received by the detection device, thus being converted into electrical signals, which are amplified by, for example, an amplifier, and finally the absorbance or the spectrogram can be displayed by the display system.

Next, the structure and layout of the atomic absorption spectrophotometer 100 according to the present invention are explained in detail with reference to fig. 2.

First, the atomic absorption spectrophotometer 100 according to the present invention includes a light source 10, and the light source 10 can emit a light beam having a characteristic wavelength spectrum line that can be absorbed by an element to be measured in a sample (or a sample solution) for subsequent measurement.

In order to ensure the measurement of peak absorption, the light source 10 must emit a sharp spectrum narrower than the width of the absorption line, and have a high and stable intensity, low background, low noise, and long lifetime. It is known that hollow cathode lamps, electrodeless discharge lamps, vapor discharge lamps and laser source lamps all meet the above requirements, with hollow cathode lamps and electrodeless discharge lamps being the most common.

Then, hollow cathode lamps are classified into, for example, single-element lamps and multi-element lamps according to the difference in cathode material. Typically, single element hollow cathode lamps can only be used for the determination of one element, which lamps emit light with low interference and high intensity, but require the replacement of one lamp for each element to be determined. The multi-element lamp can continuously measure several elements, reduces the trouble of changing the lamp, but has weak light intensity and is easy to generate interference.

Secondly, the atomic absorption spectrophotometer 100 according to the present invention should also include an atomizer. The atomizer is arranged downstream of the light source 10, seen in the direction of propagation of the light beam. As described above, the process of converting the element to be measured in the sample (or the sample solution) into gaseous ground state atoms is referred to as "atomization" of the sample. The equipment used to accomplish the atomization of the sample is known as an atomizer. The method for atomizing the detected element in the sample mainly comprises a flame atomization method and a non-flame atomization method. Flame atomization methods use the heat energy of a flame to convert a sample into gaseous atoms. The non-flame atomization method converts a sample into gaseous atoms by means of electric heating or chemical reduction and the like. The mass of the atomizer itself generally has a large impact on the sensitivity and accuracy of atomic absorption spectroscopy.

The atomizer of the atomic absorption spectrophotometer 100 according to the present invention employs a flame atomizer 20. Flame atomization mainly comprises two steps: the sample solution is first turned into fine droplets (i.e., an atomization stage), and then the droplets are subjected to energy supplied by a flame to form a ground-state atomic vapor (i.e., an atomization stage).

The flame atomizer 20 may include, for example, an atomizer and a burner, but may also include only a burner. The atomizer is used for atomizing a sample (or a sample solution) into tiny droplets. The performance of the atomizer affects sensitivity, measurement accuracy, chemical interference, etc., and thus, it is required to have stable spray, fine and uniform droplets, and high atomization efficiency. In a preferred embodiment, the flame atomizer 20 may include a premixing chamber (also referred to as an atomizing chamber) that functions to further refine the droplets and uniformly mix them with the fuel gas into the flame.

The burner of the flame atomizer 20 is operative to atomize sample particles entering the flame by forming a flame from the combustion gases in the presence of the combustion gases. The most commonly used flame for atomic absorption spectroscopy is an air-acetylene flame or nitrous oxide (laughing gas) -acetylene flame. When different combustion gases are used, the slit width and length of the burner should be adjusted to adapt to the combustion rate of different combustion gases to prevent backfire explosion.

Compared with a graphite furnace atomizer, the flame atomization method is simple and convenient to operate, good in reproducibility, large in effective optical path and wide in application because of high sensitivity to most elements. However, the flame atomization method has low atomization efficiency and insufficient sensitivity, and generally cannot directly analyze a solid sample.

The atomic absorption spectrophotometer 100 according to the present invention may further include a spectroscopic assembly 30 (also referred to as a "monochromator") that functions to separate the absorption line of the element to be measured in the sample from other lines, mainly lines adjacent to the absorption line, and may also block other lines from entering the detection assembly 40 so that the detection assembly 40 only accepts resonant absorption lines. The light-splitting means 30 is arranged downstream of the atomizer, in the present invention the flame atomizer 20, as seen in the direction of propagation of the light beam. In a preferred embodiment, the monochromator may comprise components such as an entrance slit, an exit slit and a dispersive element (e.g. a grating).

The atomic absorption spectrophotometer 100 according to the present invention may further include a detection device 40, the detection device 40 being disposed downstream of the spectroscopic device 30 as viewed in the beam propagation direction. The aforementioned light splitting means 30 may be arranged to direct light of a specific wavelength towards the detection means 40. The detection device 40 is configured to convert the optical signal into an electrical signal, which is then converted into an absorbance value by internal software design or by control of another controller. In some embodiments, the absorbance value may be directly reconverted to concentration (in units of ppm, i.e., parts per million concentration, for example). The relationship between the electrical signal and absorbance and the absorbance and concentration may be determined from a graph pre-stored in the detection device 40 or other controller, for example, the absorbance value corresponding to a particular electrical signal (e.g., in volts) on the graph may be learned.

In a preferred embodiment, the detection device 40 may include a photoelectric converter and signal processing, display recorder, etc. A commonly used photoelectric converter is a photomultiplier, which is a device that converts a weak optical signal into an electrical signal by amplifying an optical current using secondary electron emission. The amplifier is used for amplifying the voltage signal output by the photomultiplier and then sending the amplified voltage signal to the display.

It will be appreciated that in order to analyze the concentration or content of the measured element in the test sample, it is necessary to obtain a reference electrical signal by passing the beam through the atomic vapor 200 of the sample prior to the analytical test. This process may also be referred to as calibration of the atomic absorption spectrophotometer 100 to exclude as much as possible various interfering factors of the measurement.

The atomic absorption spectrophotometer 100 according to the present invention further comprises a light beam directing device arranged between the light source 10 and the light splitting device 30, in particular in the vicinity of the atomizer, to be able to direct the light beam from the upstream light source 10 through the atomic vapour 200 of the aforementioned sample and to again direct the light beam to the light splitting device 30 located downstream of the atomizer.

In the prior art shown in fig. 1, the light beam emitted from the light source 10 passes through the atomic vapor 200 only once and reaches the subsequent monochromator. Therefore, the light beam is absorbed by the ground-state atoms while passing through the atomic vapor 200 of the sample only once (passing through the atomic vapor 200 from right to left in fig. 1) to attenuate the light energy in the light beam. Due to the limited degree of attenuation, the electrical signal values received in the subsequent detection device 40 change less than the reference electrical signal value, sometimes even not to a degree where a change is detectable.

In contrast, the beam directing apparatus of the atomic absorption spectrophotometer 100 according to the present invention may include a first mirror 52 and a second mirror 54. The first mirror 52 and the second mirror 54 are respectively disposed on opposite sides thereof in such a manner as to face the atom vapor 200. As clearly shown in fig. 2, the first mirror 52 and the second mirror 54 are located on the left and right sides of the flame atomizer 20, mainly the atomic vapor 200 formed by flame combustion.

In the present disclosure, the term "opposing sides" means that the two mirrors are located on different sides of the atomic vapor 200, are arranged opposite to each other, and both face the atomic vapor 200, but it is not required that each mirror be in a fully 180 degree opposed position, as long as the two mirrors are arranged relative to each other and oriented relative to the angle of the atomic vapor 200: the light beam impinging on one of the mirrors may pass through the atom vapor 200 located between the two mirrors to the other mirror and continue from the other mirror through the atom vapor 200 again.

In addition, it is preferable that at least one of the plurality of mirrors, particularly all of the mirrors involved in the beam guiding apparatus according to the present invention is a plane mirror, rather than a curved mirror, so that a desired optical path of the beam through the atomic vapor is achieved with the simplest structure and the best reflection efficiency.

Thus, the light beam from the light source 10 can pass through the atomic vapor 200 (referred to as "first pass" in the present invention) to reach or impinge on the first reflector 52. The light beam that passes through the atom vapor 200 for the first time may be directly from the light source 10, but may also be a reflected light beam that has passed through another mirror. In the present disclosure, the term "pass through" means that the light beam propagates through at least a portion of the atomic vapor 200, preferably along the largest diameter of the physical extent of the atomic vapor 200, through the atomic vapor 200.

The light beam is irradiated onto the first mirror 52, reflected by the first mirror 52 so as to continue to be irradiated toward the atom vapor 200, and passes through the atom vapor 200 a second time and then is irradiated onto the second mirror 54. Then, the light beam is re-reflected by the second mirror 54 to continue to be irradiated toward the atom vapor 200, and passes through the atom vapor 200 for a third time.

To this end, the light beam emitted from the light source 10 and passing through the atomic vapor 200 (for the first time) is reflected on the first mirror 52 and the second mirror 54 successively before reaching the downstream light-splitting device 30, thereby passing back and forth through the atomic vapor 200 (i.e., passing through the atomic vapor 200 successively for the second time and the third time). In the present invention, the term "traverse" refers to irradiating through the atomic vapor 200 in opposite directions to each other (i.e., one-by-one traverse), but not necessarily traversing along the same path, e.g., along paths that are staggered from each other.

Subsequently, the light beam that has passed through the atom vapor 200 for the third time by means of the second mirror 54 is irradiated to the light splitting device 30 or other subsequent devices. The light beam that has passed through the atom vapor 200 for the third time may preferably be reflected by other mirrors before reaching the light splitting device 30.

Because according to the utility model discloses can make the light beam pass atomic steam 200 triples in the flame, only pass once among the prior art and compare, can show the luminous energy that is absorbed by the element that awaits measuring of sample in the increase light beam to follow-up electric signal value variation volume of learning in detection device 40 or other controllers is more showing, has expanded atomic absorption spectrophotometer's the limit of examining from this, has improved the detection precision.

In a preferred embodiment, the beam directing apparatus of atomic absorption spectrophotometer 100 may also include a third mirror 56. The third reflector 56 is arranged with respect to the light source 10 and the first reflector 52 such that: the light beam from the light source 10 is irradiated thereon, reflected (for the first time) by the third mirror 56, passes through the atom vapor 200, and is irradiated on the first mirror 52.

By means of the arrangement of the first reflector, the second reflector and the third reflector, the light beam only passes through atomic steam three times in the whole light path, so that the light intensity loss caused by the reflection of the light beam on the reflectors can be greatly reduced, and the detection efficiency of the whole atomic absorption spectrophotometer is maximized. In other words, in the present invention, it is not necessary to provide additional mirrors on both sides of the atomic vapor or disposed around the atomic vapor, and thus a compact layout can be ensured while reducing reflection loss.

In addition, the beam directing apparatus of the atomic absorption spectrophotometer 100 may further include a fourth mirror 58. The fourth mirror 58 is arranged with respect to the second mirror 54 and the light splitting device 30 such that: the light beam reflected by the second mirror 54 to pass through the atom vapor 200 (for the third time) is irradiated thereon, and is irradiated on the subsequent light splitting device 30 or other equipment via the reflection by the fourth mirror 58.

In the present invention, therefore, the following optical path is advantageously formed, viewed in the direction of propagation of the light beam: the light beam emitted from the light source 10 first passes through the atomic vapor 200 in the flame by reflection of the third reflecting mirror 56, then passes through the atomic vapor 200 a second time by reflection of the first reflecting mirror 52, then passes through the atomic vapor 200 a third time by reflection of the opposite second reflecting mirror 54, and finally is reflected by the fourth reflecting mirror 58 onto the light splitting device 30.

As exemplarily shown in fig. 2, the first mirror 52 is preferably disposed on a side of the flame atomizer 20 facing the light-dividing device 30, and the second mirror 54 is preferably disposed on a side of the flame atomizer 20 facing the light source 10, the two mirrors facing and opposing each other. In a preferred embodiment, first mirror 52 may be disposed at the same level as second mirror 54, but offset from each other (i.e., offset back and forth in a direction perpendicular to the plane of the paper). In other embodiments, the first mirror 52 and the second mirror 54 may be angled, i.e., not parallel to each other. For example, the first mirror may be angled with respect to the vertical, while the second mirror extends in the vertical direction.

In a particularly advantageous embodiment, at least one, and preferably both, of third mirror 56 and fourth mirror 58 are arranged in a perpendicular orientation to both first mirror 52 and second mirror 54. For example, as exemplarily shown in FIG. 2, third mirror 56 and fourth mirror 58 are oriented out of the page, while first mirror 52 and second mirror 54 are oriented perpendicular to the page, and thus in a generally perpendicular orientation relationship therebetween. This perpendicular orientation between the first and second mirrors and the third and fourth mirrors may allow the chance of interference of the reflected paths therebetween to be substantially reduced, thereby facilitating a compact layout of the beam directing device.

In a preferred embodiment, the actual orientation of at least one of first mirror 52, second mirror 54, third mirror 56, and fourth mirror 58 is adjustable, thereby changing the angle of reflection of the light beam and thus changing the beam propagation path. Thus, tuning of the specific region of the atomic vapor 200 passing through the flame can be achieved.

In one particular embodiment, third mirror 56, fourth mirror 58, second mirror 54, and first mirror 52 are all on the same horizontal plane (i.e., at the same height relative to atomic vapor 200), and the four mirrors are offset back and forth in a direction perpendicular to the plane of the paper, and their back and forth positions are offset just such that third mirror 56 is at 45 to the beam of light emitted by light source 10 (i.e., the angle of incidence of the beam of light incident on the third mirror is 45).

Then, the light beam reflected from the third mirror passes through the atomic vapor for the first time to reach the first mirror 52. First mirror 52 is positioned at an angle of 85 deg. to the beam reflected off third mirror 56 (i.e., the angle of incidence of the beam on the first mirror is 5 deg.).

The beam reflected off first mirror 52 then passes through the atomic vapor a second time to reach second mirror 54. The second mirror 54 is also positioned at an angle of 85 to the beam reflected off the first mirror 52 (i.e., the angle of incidence of the beam on the first mirror is 5). The light beam reflected by the second mirror 54 passes through the atomic vapor a third time to reach the fourth mirror 58.

The fourth mirror 58 is positioned at 45 to the beam reflected from the second mirror 54 (i.e., the incident angle of the beam incident on the fourth mirror is 45). Finally, the light beam reflected by the fourth mirror 58 reaches the light splitting device 30.

It is to be understood that the incident angles provided by the four mirrors of the present invention may be different from the above-described embodiments, and the four incident angles themselves may also be different from each other, which may be determined according to different application scenarios.

Although various embodiments of the present invention have been described with reference to an example of an atomic absorption spectrophotometer in the various figures, it should be understood that embodiments within the scope of the present invention may be applied to other sample analysis and detection instruments and the like having similar structures and/or functions.

The foregoing description has set forth numerous features and advantages, including various alternative embodiments, as well as details of the structure and function of the devices and methods. The intent herein is to be exemplary and not exhaustive or limiting.

It will be obvious to those skilled in the art that various modifications may be made, especially in matters of structure, materials, elements, components, shape, size and arrangement of parts including combinations of these aspects within the principles described herein, as indicated by the broad, general meaning of the terms in which the appended claims are expressed. To the extent that such various modifications do not depart from the spirit and scope of the appended claims, they are intended to be included therein as well.

Claims (10)

1. An atomic absorption spectrophotometer (100), comprising:

a light source (10), said light source (10) emitting a light beam having a characteristic wavelength line that is absorbed by an element to be measured in the sample;

a flame atomizer (20), the flame atomizer (20) comprising an atomizing device configured to atomize a sample and a combustion device configured to atomize the atomized sample into an atomic vapor (200) by combustion;

-a light splitting device (30), said light splitting device (30) being adapted to separate said characteristic wavelength spectrum of said element to be measured from other spectra in the light beam;

characterized in that the atomic absorption spectrophotometer (100) further comprises:

a beam guiding device arranged between the light source (10) and the light splitting device (30) for guiding a beam of light from the light source (10) through the atom vapor (200) and to the light splitting device (30);

wherein the beam guiding device comprises:

a first mirror (52) and a second mirror (54), the first mirror (52) and the second mirror (54) being arranged to face the atomic vapor (200) and to oppose each other, the first mirror (52) being arranged on a side of the atomic vapor (200) facing the light splitting device (30), and the second mirror (54) being arranged on the other side of the atomic vapor (200) facing the light source (10); and

a third mirror (56) and a fourth mirror (58), the third mirror (56) being arranged between the light source (10) and the atom vapor (200), and the fourth mirror (58) being arranged between the atom vapor (200) and the light-splitting device (30);

forming the following optical path of the light beam by means of the first mirror, the second mirror, the third mirror and the fourth mirror: the light beam from the light source (10) passes through the atomic vapor (200) by reflection from the third mirror, then passes through the atomic vapor (200) again back and forth once by successive reflection on the first mirror and the second mirror, and then impinges on a fourth mirror (58) to be directed toward the light splitting device (30) by reflection from the fourth mirror (58).

2. The atomic absorption spectrophotometer (100) of claim 1, wherein said first mirror (52) and said second mirror (54) are each planar mirrors.

3. The atomic absorption spectrophotometer (100) of claim 2, wherein said third mirror (56) and said fourth mirror (58) are each planar mirrors.

4. The atomic absorption spectrophotometer (100) of claim 1, wherein at least one of said third mirror (56) and said fourth mirror (58) is arranged in a perpendicular orientation to said first mirror (52) and said second mirror (54).

5. The atomic absorption spectrophotometer (100) of claim 1, wherein an orientation of the first mirror (52) and/or the second mirror (54) is adjustable.

6. The atomic absorption spectrophotometer (100) of claim 1, wherein an orientation of the third mirror (56) and/or the fourth mirror (58) is adjustable.

7. The atomic absorption spectrophotometer (100) of claim 1, wherein said first mirror (52) and said second mirror (54) are disposed at a same height relative to said atomic vapor (200) and offset from each other.

8. The atomic absorption spectrophotometer (100) of claim 1, wherein said first mirror (52) is inclined with respect to a vertical direction and said second mirror (54) extends in the vertical direction.

9. The atomic absorption spectrophotometer (100) of any one of claims 1 to 8, wherein the atomic absorption spectrophotometer (100) further comprises a detection device (40), the detection device (40) being arranged to convert a beam of light split by the splitting device (30) into an electrical signal to learn the concentration of the element to be measured of the sample.

10. The atomic absorption spectrophotometer (100) of claim 9, wherein the light source (10) is a hollow cathode lamp or an electrodeless discharge lamp.

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