CN211905076U - A Simultaneous Detection System for Inductively Coupled Plasma Atomic Mass Spectrometry and Spectroscopy - Google Patents

Abstract

The utility model discloses a simultaneous detection system for inductively coupled plasma atomic mass spectrometry and spectrum, comprising an inductively coupled plasma source, a mass spectrum detection system and a spectrum detection system; the spectrum detection system consists of a hollow cathode lamp, a spectrum detector and a spectrum detection control module Composition: Atomic mass spectrum signals are collected in the axial direction of the inductively coupled plasma, and atomic emission and absorption spectrum signals are collected in the radial direction. The utility model shares one inductively coupled plasma source, and integrates the detection of atomic mass spectrometry, atomic emission spectrum and atomic absorption spectrum in the same ion source/excitation source/atomicizer, and can inject samples at one time, and simultaneously measure atomic mass spectrometry, atomic emission and atomic absorption spectrum. Atomic absorption spectroscopy, thus reducing sample and reagent consumption, saving analysis time, reducing instrument costs and operating and maintenance costs.

Description

A Simultaneous Detection System for Inductively Coupled Plasma Atomic Mass Spectrometry and Spectroscopy

technical field

The utility model relates to the technical field of plasma technology and atomic mass spectrometry and spectrum analysis, in particular to a simultaneous detection system of inductively coupled plasma atomic mass spectrometry and spectrum.

Background technique

Inductively Coupled Plasma, ICP is one of the most mature and most concerned plasma technologies currently in commercial use. Its high electron density and temperature, high gas dynamic temperature, strong excitation and ionization ability, can atomize and excite almost all elements, and ionize most elements, so it is widely used in the field of atomic mass spectrometry and spectral analysis instruments. , used as ion source for atomic mass spectrometry, atomizer/excitation source for atomic mass spectrometry. Among them, the atomic mass spectrometer using inductively coupled plasma as the ion source and the atomic emission spectrometer as the excitation source are the most successful, and they have been widely used in sample analysis and detection, scientific research and production in various fields.

Inductively Coupled Plasma-Mass Spectrometry Inductively Coupled Plasma-Mass Spectrometry, ICP-MS has been widely used in the analysis of trace elements in food, biology, environment and other fields. It is a method of vaporizing, atomizing, and ionizing the element to be tested, and then separating and screening different element ions through different mass-to-charge ratios m/z, and finally detecting. Traditional commercial quadrupole ICP-MS is generally composed of sample introduction system, ion source, mass analyzer and detector. The sample introduction system is mostly pneumatic nebulizer, the ion source is ICP, the mass analyzer is a quadrupole, and the detection The device is an electron multiplier. It can accurately quantify trace elements and isotopes, and can detect multiple elements simultaneously in a wide linear range, with a wide dynamic range and very superior detection limits. However, isotopic mass spectrometry and non-mass spectrometry interferences always exist in atomic mass spectrometry. Only some of the more advanced techniques can improve the analytical performance of mass spectrometry, increase resolution, reduce interference, and obtain a wider linear dynamic range. Among them, the more common techniques are collision/reaction cells, tandem analyzers, and high-resolution techniques such as magnetic mass spectrometry. However, the high cost of these technologies limits their widespread application. In addition, in order to obtain more accurate results of high-sensitivity mass spectrometry, high-purity reagents or reagent purification systems are usually required to be used together, which usually makes these devices more complicated, and the testing takes more time and cost.

Inductively Coupled Plasma-Optical Emission Spectrometry Inductively Coupled Plasma-Optical Emission Spectrometry, ICP-OES is generally less sensitive than Inductively Coupled Plasma Atomic Emission Spectrometry. However, because of its relatively low instrument cost, operation and maintenance costs, and its suitability for multi-element simultaneous analysis of various samples, it has a wide range of applications in routine analysis. However, in atomic emission spectroscopy systems, many elements have similar atomic emission lines, and spectral overlap interference is usually unavoidable. In the ICP excitation source, there are not only atomic emission lines, but also ion emission lines and molecular emission bands that often produce large spectral overlap interferences. For molecular emission spectrum, because of its broad emission peaks, it has a large overlap with the atomic emission lines of many elements, so that some atomic emission lines cannot be used as analytical lines for qualitative and quantitative analysis of elements. On the other hand, for spectroscopic detectors, there is always the limitation of the physical spectral resolution limit; therefore, in ICP-OES systems, it is also impossible to completely resolve the atomic emission spectral lines of elements.

Inductively Coupled Plasma-Atomic Absorption Spectrometry, ICP-AAS is an early method developed in ICP-OES spectroscopy. The biggest difference between it and atomic emission spectroscopy is that in addition to the atomizer, an additional absorption light source, usually a sharp-line light source, is required. Due to the use of a sharp-line light source, a large number of spectral line interference problems in atomic emission spectrometry can be effectively avoided; at the same time, its sensitivity is usually better than that of ICP emission spectroscopy. However, for some elements with strong molecular binding force, free atoms cannot be released when the ICP works at a lower power, and excitation and ionization are easy to occur at a higher power, making it difficult to detect the atoms in the ICP. absorbs the signal, thereby limiting the range of elements that can be detected and applied by ICP-AAS. Although studies of ICP-AAS have been reported, stand-alone commercial instruments are still rare.

At present, ICP-based instruments including ICP-MS and ICP-OES are relatively expensive analytical equipment in general laboratories. Not only the cost of the instrument itself is high, but also the cost of consumables and maintenance in the later use process. All of them cannot be equipped as conventional analytical instruments in most analytical and scientific research laboratories, and it is even more difficult to equip multiple ICP instruments at the same time. However, in the actual production and scientific research process, a single device often cannot completely solve the complex problems encountered. From the perspective of the structure of the instrument, ICP spectrometers including ICP-OES, ICP-AAS and ICP mass spectrometer ICP-MS have similar parts, and all use ICP sources to achieve ionization, atomization or spectral excitation; the difference lies in The optical path and the detection part, and the measurement principles of the three are different at the same time, and the measurement can not interfere with each other, so it has the possibility of potential simultaneous detection. In addition, in the ICP source, the atoms of the analyzed elements are in a complex state, which may be in the atomic ground state and atomic excited state, or may be in the ionic ground state and ion excited state. If there is a free atom A in the ground state, the corresponding atomic absorption spectrum signal AAS is generated; if there is an atom A* in the excited state, there is an atomic emission spectrum signal AES/OES; If there is an ionized ion A ⁺ , there is The atomic mass spectrometry signal MS, and the ion absorption signal; if there is an excited state ion A ⁺ *, the corresponding ion emission spectrum signal is generated. Multiple particles may exist singly or in combination in the ICP source; if they exist in combination, corresponding multiple signals will be generated simultaneously.

To sum up, if ICP-MS, ICP-OES, and ICP-AAS can be integrated together, and the simultaneous detection of atomic mass spectrometry, atomic spectroscopy including atomic emission spectroscopy and atomic absorption spectroscopy can be realized, ICP- The three functions of MS, ICP-OES and ICP-AAS give full play to the complementary advantages of the three; it can also form a new type of analytical instrument and obtain new functions that a single instrument does not have. Under the condition of one sample injection, the simultaneous measurement of atomic mass spectrometry, atomic emission spectrum and atomic absorption spectrum can be realized, and the comprehensive analysis performance of the instrument can be improved, including: reducing the consumption of samples and reagents, saving analysis time, reducing instrument cost and use and maintenance Cost; expand the linear range of the instrument’s working curve and the range of sample elements and concentrations that can be directly analyzed. Multiple detection methods cooperate with each other to eliminate the mass spectral interference or spectral interference of a single method. The measurement results of the three detection methods can be compared with each other to verify the analysis results. Accuracy and expand the application range of ICP-MS, ICP-OES and ICP-AAS.

Utility model content

In view of the above-mentioned problems, the purpose of this utility model is to provide a system for simultaneous detection of atomic mass spectrometry, atomic emission spectroscopy and atomic absorption spectroscopy based on sharing an inductively coupled plasma source, improving a single ICP-MS, ICP-OES and ICP-AAS The comprehensive analytical performance of the system increases new functions and application potential, and expands the application scope of atomic mass spectrometry and spectroscopy-based analytical instruments. The technical solution is as follows:

A simultaneous detection system for inductively coupled plasma atomic mass spectrometry and spectroscopy, comprising an inductively coupled plasma source, a mass spectrometry detection system and a spectrum detection system;

The inductively coupled plasma source includes a plasma torch and an inductively coupled plasma; the plasma torch is connected to the sample introduction system, and the inductively coupled plasma is generated at the end of the torch;

The mass spectrometry detection system includes a mass spectrometry detection unit, which is arranged in the axial direction of the inductively coupled plasma source, receives ionized ions in the inductively coupled plasma, and obtains an atomic mass spectrometry signal response;

The spectral detection system includes a hollow cathode lamp, a spectral detector and a spectral detection control module;

The excited atoms in the inductively coupled plasma return to the low-energy state from the excited state, and at the same time radiate light of its characteristic wavelength, which is received by the spectral detector, and the atomic emission spectral signal response is obtained at the radial position;

The atomized atoms in the inductively coupled plasma absorb the incident light of the hollow cathode lamp light source, and the incident light whose absorption is weakened is then received by the spectrum detector, and the atomic absorption spectrum signal response is obtained at the radial position;

The spectral detection control module connects the spectral detector and the hollow cathode lamp at the same time, controls the spectral detection and the modulation of the light source, and realizes the simultaneous detection of the atomic emission spectrum and the atomic absorption spectrum.

Further, it also includes a focusing lens and a focusing adjustment unit; the focusing lens focuses the light radiated from the inductively coupled plasma during emission spectrum detection, and focuses the hollow cathode lamp light source during absorption spectrum detection; the focusing adjustment unit is used to adjust The focal position of the light focused by the focusing lens.

The beneficial effects of the present utility model are:

1) In situ simultaneous detection combined with three independent and non-interfering detection methods, the three analysis results complement each other, which can expand the linear range of the instrument’s working curve and the range of sample elements and concentrations that can be directly analyzed. Analysis of samples in the mid to high concentration range. The high sensitivity of ICP-MS can meet the high sensitivity requirements constantly put forward in analytical science, while ICP-OES and ICP-AAS determination can meet the routine trace analysis. More suitable detection methods can be selected according to different elements and concentration samples. Efficiently obtain more accurate and reliable measurement results;

2) Multiple detection methods cooperate with each other to eliminate the mass spectral interference or spectral interference of a single method; more suitable detection methods can be selected according to the interference of different sample matrices to obtain more accurate and reliable measurement results;

3) The accuracy of the analysis results can be verified by the mutual self-comparison of the measurement results of various detection methods; the self-comparison and calibration of the results can be realized by one instrument and one injection, which improves the time and space consistency of the data results and overcomes certain problems. some difficulties in the analysis of non-standard reference materials;

4) Simultaneous detection of atomic mass spectrometry, atomic emission spectrometry and atomic absorption spectrometry is accomplished through one injection, which can effectively reduce the consumption of samples and reagents, save analysis time, and reduce instrument costs and use and maintenance costs;

5) Through the simultaneous measurement of multiple principles of atomic mass spectrometry, atomic emission spectroscopy and absorption spectroscopy, it is expected to form a new type of analytical instrument and expand the application range of the instrument, such as providing more information for the study of some reaction mechanisms, and for plasma analysis. Research provides new tools and more.

Description of drawings

Fig. 1 is the device structure schematic diagram of the simultaneous detection system of inductively coupled plasma atomic mass spectrometry, atomic emission spectrum and absorption spectrum of the present invention;

In the figure: 1. Sample, 2. Injection pipeline, 3. Nebulization system, 4. Plasma torch, 5. Inductively coupled plasma, 6. Mass detection unit, 7. Hollow cathode lamp, 8. Focusing lens , 9. Focus adjustment unit, 10. Spectral detector, 11. Spectral detection control module.

Fig. 2 is the present utility model inductively coupled plasma atomic mass spectrometry, atomic emission and absorption spectrum to simultaneously measure the emission and absorption spectrum signals of Cd element. Among them, the abscissa represents the spectral signal wavelength, and the ordinate represents the signal intensity.

3 is a graph showing the change of the signal intensity of the inductively coupled plasma atomic mass spectrometry, atomic emission and absorption spectroscopy of the present invention, and measuring the mass spectrum, emission and absorption spectral signals of Cd elements with the change of radio frequency power in one sample injection process.

FIG. 4 is a timing chart of the atomic emission spectrum signal of the inductively coupled plasma atomic mass spectrometry, atomic emission and absorption spectrum of the present invention for simultaneous determination of Cd. The abscissa represents the time, the ordinate represents the signal strength, each point represents a measurement result, and the relative standard deviation of more than 6,000 sampling results is less than 3%.

Figure 5 shows the simultaneous detection of inductively coupled plasma atomic mass spectrometry, atomic emission and absorption spectrometry of the present invention. Under the condition of one sample injection, Mn element obtains a standard curve with a wider linear range.

FIG. 6 shows the simultaneous detection of inductively coupled plasma atomic mass spectrometry, atomic emission and absorption spectroscopy of the present invention to eliminate the interference of single mass spectrometry.

FIG. 7 shows the simultaneous detection of inductively coupled plasma atomic mass spectrometry, atomic emission and absorption spectroscopy of the present invention to eliminate the interference of single atomic emission spectroscopy.

Fig. 8 is the standard curve obtained by the simultaneous detection of inductively coupled plasma atomic mass spectrometry, atomic emission and absorption spectrometry of the present invention, and the simultaneous detection of different elements of high concentration and low concentration under the condition of one sample injection.

Detailed ways

The present utility model will be further described in detail below with reference to the accompanying drawings and specific embodiments. The utility model combines the principles of inductively coupled plasma atomic mass spectrometry, inductively coupled plasma atomic emission spectrometry and atomic absorption spectrometry and the similarities of the instrument structure, and shares an inductively coupled plasma source as an ion source, an excitation source and an atomizer. Different physical quantity signals are obtained through different signal acquisition positions and timing control, and the simultaneous detection of atomic mass spectrometry, atomic emission spectrum and absorption spectrum in the same ion source, excitation source and atomizer is realized. The sample analyte is evaporated, dissociated, atomized, ionized and excited in the inductively coupled plasma ion source/excitation source/atomicizer, and the ionized ions are axially transmitted into the mass spectrometer to obtain the atomic mass spectrometry signal response ; The excited atoms return to the low-energy state from the excited state and radiate light of its characteristic wavelength at the same time, so as to obtain the atomic emission spectrum signal response at the radial position; the atomized atoms absorb the incident light of the hollow cathode light source, AAS signal responses were also obtained at radial positions.

The atomic emission and atomic absorption of the spectrum detection system share a set of optical system, and the simultaneous detection of the atomic emission spectrum and the atomic absorption spectrum is regulated by the timing control module. The atomic mass spectrometry signal is collected in the axial direction of the inductively coupled plasma, and the atomic emission spectrum and atomic absorption spectrum signals are collected in the radial direction without interfering with each other.

As shown in Figure 1, the inductively coupled plasma atomic mass spectrometry, emission and absorption spectra of the present utility model are simultaneously detected, including a sample injection part, an inductively coupled plasma, a mass spectrometry detection system and a spectral detection system. The injection part includes sample 1 , injection pipeline 2 and atomization system 3 .

The inductively coupled plasma source includes a plasma torch 4 and an inductively coupled plasma 5; the plasma torch 4 is connected to the sample introduction system, and generates an inductively coupled plasma 5 at the end of the torch.

The mass spectrometry detection system includes a mass spectrometry detection unit 6, which is arranged in the axial direction of the inductively coupled plasma source, receives ions ionized in the inductively coupled plasma 5, and obtains an atomic mass spectrometry signal response.

The spectral detection system includes a hollow cathode lamp 7, a spectral detector 10 and a spectral detection control module 11; the excited atoms in the inductively coupled plasma 5 return to a low-energy state from an excited state and radiate light of its characteristic wavelength at the same time. It is received by the spectral detector 10, and the atomic emission spectrum signal response is obtained at the radial position; the atomized atoms in the inductively coupled plasma 5 absorb the incident light of the light source of the hollow cathode lamp 7, and the incident light whose absorption is weakened is then converted into the spectrum by the atomized atoms. The detector 10 receives and obtains the atomic absorption spectrum signal response at the radial position; the spectrum detection control module 11 connects the spectrum detector 10 and the hollow cathode lamp 7 at the same time, controls the spectrum detection and light source modulation, and realizes the atomic emission spectrum and the atomic absorption spectrum at the same time. detection.

The inductively coupled plasma atomic mass spectrometry, atomic emission and absorption spectrum of the utility model are simultaneously detected, and under the condition of one sample injection, the specific process of obtaining the atomic mass spectrometry, atomic emission and absorption spectrum signals is as follows:

1) Insert the sample injection tube into the sample solution, the sample solution is atomized to form an aerosol and introduced into the argon flow, and enter the central area of the inductively coupled plasma;

2) In the inductively coupled plasma, the sample elements are desolvated, vaporized, dissociated, atomized, excited and ionized;

3) The ionized atoms of the element to be tested enter the mass spectrometer detector after passing through different pressure regions. At the same time, the element atoms in the excited state in the plasma return to the low-energy state to release characteristic emission lines and enter the spectral detector; the element atoms in the ground state absorb the characteristic incident light of the hollow cathode lamp, and the characteristic light whose absorption is weakened enters the same Spectral detector: The spectral detection part performs the synchronous work of light source modulation and spectral detection through the spectral detection control system, and realizes the simultaneous detection of atomic emission and absorption spectra.

4) The mass spectrometry signal and the spectral signal are collected synchronously; the mass spectrometry method qualitatively and quantifies the element through the mass-to-charge ratio, and the spectrometry method qualitatively and quantifies the element by the characteristic emission and absorption spectral signals of the excited state and ground state atoms; and do further follow-up required. data processing.

Table 1 shows some elements that have been verified by the utility model using inductively coupled plasma atomic mass spectrometry and emission spectrometry to detect at the same time.

Table 1 Detected emission line elements (in parentheses are the groups of elements in the periodic table)

Example 1: In this example, inductively coupled plasma atomic mass spectrometry, atomic emission and absorption spectroscopy are simultaneously detected, and three signals of Cd element are simultaneously collected through one sample injection. As shown in Figure 3, in the case of adjusting the RF power, the effects of the ICP RF power on the strength of the three signals are obtained. By studying the mutual influence and relative relationship among the three, a new detection tool can be provided for the theoretical study of the transformation process of element atoms in inductively coupled plasma.

Example 2: In this example, inductively coupled plasma atomic mass spectrometry, emission and absorption spectroscopy are simultaneously detected. Under the condition of one sample injection, and the sample solution does not need to be pre-enriched or diluted, the Mn element can obtain a wider linear range of work. curve. The sample solutions containing different concentrations of Mn elements are directly passed into the inductively coupled plasma, and are simultaneously detected by the atomic mass spectrometry, atomic emission and absorption spectroscopy of the utility model. As shown in Fig. 5, in the process of measuring Mn, when the concentration is 1-2000 μg L ^-1 , it can be easily determined by mass spectrometry detection, and a linear range of 1 μg L ^-1 to 2 mg L ^-1 can be obtained; by atomic For emission spectrometry, the linear range of the system will extend further up to 50 mg L ^-1 or even higher, depending on the dynamic range of the signal response of the detector unit used for the emission spectroscopic signal. By combining the two, a wider range of elemental quantification working curves can be obtained. No matter the concentration range of Mn element in the sample is in μg L ^-1 level or mg L ^-1 level, only one injection is needed to complete the concentration measurement. It should be pointed out that the main reason why the linear range of this embodiment cannot be wider is that the CCD detector used in the embodiment is saturated, and the use of a detector with a wider dynamic range can further expand the linear range.

Embodiment 3: In this embodiment, inductively coupled plasma atomic mass spectrometry, atomic emission and absorption spectroscopy are simultaneously detected, and the interference of atomic mass spectrometry detection is eliminated by atomic emission spectrometry detection. As shown in Figure 6, when Fe elements are tested by mass spectrometry, the ^presence of ^Cr , ^Ca , and ^Ni will interfere with the ^mass spectrum signal of ^Fe . The signal can avoid this interference.

Embodiment 4: In this embodiment, inductively coupled plasma atomic mass spectrometry, atomic emission and absorption spectroscopy are simultaneously detected, and the interference of atomic emission spectroscopy detection is eliminated by atomic mass spectrometry detection. As shown in Figure 7, when the Cu element is measured by spectrometry, when the sample contains Zn or P element, it will affect the emission spectrum of Cu, and mass spectrometry can avoid this situation.

Example 5: Simultaneous detection of inductively coupled plasma atomic mass spectrometry, atomic emission and absorption spectrometry in this example, when the mixed solution of Cd, Ni, Mn and Zn was injected once, the low concentration μg L ^-1 level of Cd obtained by mass spectrometry and the working curves of Ni elements, and the working curves of Mn and Zn elements at high concentration mg L ^-1 levels obtained by emission spectroscopy. When multiple elements are measured at the same time, there is no need to dilute or pre-enrich the sample, and different determination methods can be directly selected according to the concentration range of the element to be measured. Therefore, this method is advantageous for analyzing precious samples with very small sample volumes.

Claims (2)

1. A simultaneous detection system for atomic mass spectrometry and spectrum of inductively coupled plasma is characterized by comprising an inductively coupled plasma source, a mass spectrometry detection system and a spectrum detection system;

the inductively coupled plasma source comprises a plasma torch tube (4) and inductively coupled plasma (5); the plasma torch tube (4) is connected with the sample introducing system and generates inductively coupled plasma (5) at the tail end of the torch tube;

the mass spectrum detection system comprises a mass spectrum detection unit (6) which is arranged in the axial direction of the inductively coupled plasma source, receives ionized ions in the inductively coupled plasma (5) and obtains atomic mass spectrum signal response;

the spectrum detection system comprises a hollow cathode lamp (7), a spectrum detector (10) and a spectrum detection control module (11);

the excited atoms in the inductively coupled plasma (5) return to a low energy level state from an excited state and simultaneously radiate light with characteristic wavelength, and the light is received by a spectrum detector (10) to obtain atomic emission spectrum signal response at a radial position;

after the atoms atomized in the inductively coupled plasma (5) absorb the incident light of the light source of the hollow cathode lamp (7), the incident light with weakened absorption is received by the spectrum detector (10), and the atomic absorption spectrum signal response is obtained at the radial position;

the spectrum detection control module (11) is simultaneously connected with the spectrum detector (10) and the hollow cathode lamp (7) to control spectrum detection and light source modulation, so that simultaneous detection of an atomic emission spectrum and an atomic absorption spectrum is realized.

2. The system for simultaneous detection of inductively coupled plasma atomic mass spectrometry and spectroscopy of claim 1, further comprising a focusing lens (8) and a focus adjustment unit (9); the focusing lens (8) focuses light rays radiated from the inductively coupled plasma (5) during emission spectrum detection, and focuses a light source of the hollow cathode lamp (7) during absorption spectrum detection; the focus adjusting unit (9) is used for adjusting the focus position of the light focused by the focusing lens (8).

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