Some standard content:
National Standard of the People's Republic of China
Terminology of emission spectrochemical analysis
Terminology of emission spectrochemical analysisGB 9259-88
This standard specifies the definition of emission spectrochemical analysis terms for use by relevant departments in domestic and international technical business exchanges. When formulating and revising standards for teaching, scientific research, abbreviating technical documents and books, when encountering emission spectrochemical analysis terms: the provisions of this standard should be implemented. For other professional terms, the relevant standards shall prevail. 1 Basic principles
1.1 Electromagnetic radiationEnergy transmitted by electromagnetic fields. The electromagnetic spectrum includes the following approximate wavelength regions: Region
Y-ray
X-ray
Far ultraviolet
Near ultraviolet
Near infrared
Mid infrared
Far infrared
1.2 Light Hight
Wavelength, nm
0. 000 5 ~ 0. 140
10.0~200.0
200. 0~-380. 0
380.0~-780.0
780, 0~3 000. 0 | | tt | 000--3 800)
(3 800--7 800)
(7 800~30 000)
(3X10t~3×105)
(3×105~3×105)
(3X10§3X101°)
Electromagnetic radiation that can cause vision impairment to ordinary people, its wavelength range is about between 380nm of violet light and 780nm of red light. Strictly speaking, this part of electromagnetic radiation should be called visible light. In addition, light in a broad sense also includes ultraviolet light and infrared light. 1.3 Spectrum spectrum
Electromagnetic radiation wavelength, wave number or frequency spectrum arranged in reverse order. 1.4
Wavelength, αwavelength
The distance between two adjacent points with the same phase at the same moment in the direction of wave propagation, 1.5 Wave number
wave number
The number of waves per unit length, that is, the reciprocal of the wavelength in vacuum. The common unit of wave number is crn-1, also known as kayser, =cm-1 1.6 cycle.T cycle
The time required to complete a full vibration.
Frequency, frequency
The number of cycles per unit time.
f=/, where is the speed of light and is the wavelength.
1.8 natural frequency
The frequency of electromagnetic waves in a vacuum.
Approved by the Ministry of Electronics Industry of the People's Republic of China on April 6, 1988 and implemented on May 1, 1989
1.9 Angstrom
GB 9259- 88
A unit for measuring tiny lengths. 1A=10-1° m. In spectral analysis, angstroms are often used to represent the wavelength of light. 1. 10 wavelength standard standard of wavelength In 1907, the International Astronomical Union decided to use the wavelength of red radiation 6438.4696 as the original standard of wavelength. The definition of angstrom is 1/6438.4696 of the wavelength of red radiation. In 1960, the conference agreed to use the red line of 6057.802106A at 84 degrees Celsius as the wavelength standard.
1, 11 nanometer (nm) nanometer
represents the unit of wavelength. 1nm=10-\m=10 A. 1.12 ground state ground state
the lowest energy state of an atom. An atom in the ground state does not emit light. Excited state excited state
an atom obtains enough energy from the ground state to transition to a higher energy state. This higher energy state is called an excited state. 1.14 Excitation of spectra When an atom or ion in the ground state obtains enough energy, it will migrate from a low energy state to a high energy state (excited state). This excited state atom or ion is extremely unstable and will immediately migrate to a low energy state and radiate a characteristic spectrum. This process is called spectral excitation. There are three main types of spectral emission: thermal excitation, electrical excitation and photoemission. 1. 15 Excitation potential The energy that an atom or ion must obtain to be excited from the ground state to a high energy state (excited state). The excitation potential is usually represented by E, and the unit is electron volt (eV).
1.16 Excitation energy
See excitation potential.
1.17 Spectral term
The energy of an electron in an atom is determined by four quantum numbers, namely the principal quantum number (n), the angular quantum number (s), the magnetic electron number (L) and the spin quantum number (J), and their interactions, and is represented by 2+11.1, which is called the spectral term of the atom. The spectral term determines the energy level of the electron.
1.18 Atomic spectra
When atoms are excited, they emit many different wavelengths of light, and the spectrum obtained after dispersion. Each element has its own characteristic spectrum. This is the basis for identifying the existence of the element and determining its content. Emission spectrum
The spectrum emitted by a substance under the emission of a light source is divided into three categories: a continuous spectrum produced by a burning solid; b band spectrum emitted by excited molecules; c line light emitted by excited atoms or ions. 1.20 Spectral line
The light generated by the light source is projected onto the slit of a spectrograph or a light meter, and then the image formed on the focal plane of the darkbox objective is the spectral line. Its width is approximately equal to the width of a monochromatic radiation pattern. 1.21 Natural line width The width of a spectral line is determined by the finite life span of an atom in a luminescent state when it is not affected by the outside world. 2 Spectral linewidth
Actual spectral lines are not strictly monochromatic, but have a certain intensity distribution within a certain frequency range. The wavelength interval at half the maximum intensity is the spectral line width. It is also called the half-width of the spectral line. 1.23 Hyperfine structure The multiple lines in the atomic mystery split into two, and the wavelength is very close to the inner line. It is called the superfine structure of the spectral line. It is mainly caused by the meta-GB 9259-88
effect and nuclear spin. It can only be observed when observing the spectrum with a spectrometer with extremely high resolution. 1.24 Stark effect
The effect of spectral item splitting caused by an external strong electric field. It is difficult for general spectrometers to separate such split spectral lines, and they can only be broadened under relative overlap, which is called Stark broadening. 1.25 Zeeman effect
The effect of spectral item splitting caused by external fields. It is difficult for a general spectrometer to separate such split spectral lines. In fact, only the broadening of the spectral lines is observed, which is called Zeeman broadening.
1.26 Self-alvorption
The light radiation emitted by the excited atoms in the center of the radiation source is absorbed by the ground state atoms of the same element in the outer area with lower temperature when passing through the vapor cloud, resulting in the phenomenon of the reduction of the intensity of the spectral line, which is called the self-absorption of the harmonic line. In the wavelength table, self-absorption is often represented by 0.
1.27 Self-reversal
Also known as self-reversal. An extreme case when the self-absorption phenomenon is serious. At this time, the original strong central intensity of the spectral line of the element is greatly weakened, so that one spectral line seems to be split into two. In the wavelength table, self-reversal is often represented by R. 1.28 Ultraviolet light
Electromagnetic radiation with a wavelength between violet light and X-rays in the electromagnetic spectrum, with a wavelength range of 10.0~380.0nm, cannot cause vision. The elemental spectra used for spectral analysis are generally in the near ultraviolet and visible light regions. 1.29 Infrared ray (radiation) is electromagnetic radiation with a wavelength between red light and infrared light in the electromagnetic spectrum.3D Spectroscopy
A branch of physical science that studies the theory of spectra and the interpretation of spectral phenomena. 1.31 Emission spectroscopyOptical emission spectroscopyA branch of spectroscopy that studies the theory, interpretation and application of spectra produced by the emission of electromagnetic radiation by atoms, ions, functional groups and molecules.
1.32 Optical emission spectroscopyOptical emission spectroscopyA sub-discipline of emission spectroscopy that refers specifically to the near ultraviolet, visible or near infrared wavelength regions of the electromagnetic spectrum. 1.33 Absorption spectroscopyAbstract spectroscopyA branch of spectroscopy that studies the theory, interpretation and application of spectra produced by the absorption of electromagnetic radiation by atoms, ions, functional groups and molecules.
1.34 Atomic absorption spectroscopyA branch of spectroscopy that studies the theory, interpretation and application of ultraviolet and visible absorption spectra of free atoms. 1.35 Atomic Fluorescence Spectroscopy A branch of spectroscopy that studies the theory, interpretation and application of spectra produced by free atoms absorbing electromagnetic radiation and being excited. 1.36 X-ray Emission Spectroscopy X-ray emission spectroscopy refers specifically to the X-ray wavelength region of the electromagnetic spectrum. 1.37 Time-resolved spectroscopy is a spectroscopy that studies the instantaneous dynamic process of the spectrum. 1.38 Plasma
A state of matter under high temperature conditions, composed of molecules, atoms, ions, electrons and excited atoms and molecules, which is generally electrically neutral and is the fourth state of matter besides solid, liquid and gas at temperature. 1.39 Thermodynamic equilibrium In a uniform light source plasma, there are gaseous molecules, atoms, ions and electrons, and there are excitation equilibrium and ionization equilibrium processes. If the gas temperature, ionization temperature, electron temperature and excitation temperature in the light source system are equal, the whole system is in a stable and balanced state, which is called thermodynamic equilibrium. If the various temperatures are not equal, it is called non-thermodynamic equilibrium. 1.40 Local thermodynamic equilibrium In a non-uniform light source plasma, the whole system has not reached a thermodynamic equilibrium state, but it has reached a thermodynamic equilibrium state in some local areas, which is called local thermodynamic equilibrium. 1.41 Boitzmann equation The equation that describes the relationship between the ratio of excited state atomic density to ground state atomic density and the spectral energy level degeneracy, spectral line excitation potential and temperature in the light source plasma under thermodynamic equilibrium conditions is: Ne
In the formula: N,, N, are the excited state and ground state atomic densities respectively: gg. ——respectively the degeneracy of excited and ground state atomic energy levels;——Boltzmann constant;
7——excitation temperature;
E, -excitation potential.
1.42 Vaporous cloud
vaporouscloud
The vapor cloud in spectral analysis is a plasma containing molecules, atoms, ions, electrons and other particles. 1.43 Saha equation
The equation describing the relationship between the ionization degree (X) of atoms in the excitation light source and the thermodynamic temperature T (K): Xt
Where: is the ionization charge, the unit is e.
logT-5040u—0.5
1.44 Atomic ionization potentialatomic ionization potentialThe minimum energy required to remove an electron from an atom is called ionization energy, also known as ionization potential, usually in eV. 1.45 Excitation potential of spectral line The minimum energy required for an atom or ion to be excited from the ground state to a certain high energy state (excited state) and emit a spectrum is called the invitation potential of the spectral line, usually in eV.
1. 46 Recombination of ion and electron The phenomenon of ions combining with the free electrons around them in plasma. During the recombination process, the kinetic energy of the free electrons will radiate outward in a continuous spectrum to form a background. This phenomenon is more obvious in spark spectra. 1.47 Atomic line atom line
A spectral line radiated by neutral atoms. Usually represented by the symbol I before the wavelength of the spectral line. 1.48 Arc line arc line
See atomic line.
1.49 Resonance line resonance line
A spectral line radiated by an atom when it directly transitions from an excited state to the ground state. The spectral line radiated when it directly transitions from the first excited state to the ground state is called the first resonance line.
1.50 Sensitive line
Generally refers to the spectrum line with lower excitation potential and greater intensity. 1.51 Persistent line When the content of an element in a sample gradually decreases, the number of spectral lines also decreases accordingly. When the content further decreases, the last spectral line that disappears is called the last spectral line of the element. 1.52 Ion line
Light line radiated by ion stimulated ionization. Usually, the symbol Ⅱ is used before the wavelength to indicate the primary ion line, and 1 indicates the secondary ion line.
1.53 Spark line
spark line
See CB 9259—88
1.54 Emission spectrochemical analysis
Emission spectrochemical analysis is a method of detecting the presence and content of an element by using the wavelength and intensity of the characteristic line spectrum emitted by atoms or ions in a sample or the wavelength and intensity of the characteristic band spectrum emitted by certain molecules or groups. 1.55 Lomakin-Scheibeequation The empirical formula for spectral quantitative analysis: I = ac6
Where: 1 is the analytical line intensity of the element with a concentration of C in the sample, a is a constant, and b is the self-absorption coefficient. 1.56 Analytical Line
The specific spectral line of the element used to determine the concentration of an element in a sample. 1. 57 Principle of internal standard In order to improve the accuracy of spectral analysis and reduce the influence of inconsistent excitation conditions on the intensity of analytical lines, matrix elements or certain quantitative elements are selected in the sample and standard sample as internal standard elements, and a balanced analytical line pair is selected. The working curve is drawn using the logarithm of the line pair intensity ratio and the logarithm of the concentration to more accurately obtain the concentration of the element in the sample. 1.58 Internal standard element When using the internal standard method for spectral quantitative analysis, an element with a certain content in the standard sample and the sample is used for comparison with the element to be determined. The internal standard element can be present in the sample or added externally. 1.59 Internal standard line A spectral line of the internal standard element, which forms an analytical line pair with the analytical line. 1.60 Internal reference line See internal standard line.
Analytical line pair Spectral line pair consisting of the analytical line and the internal standard line. Generally, it is also called a homologous line pair. 1.62 Hatmologous lines A group of spectral lines whose relative intensity changes the least due to fluctuations in the excitation conditions. 1.63 Homologous line pair A line pair consisting of spectral lines emitted by electrons of the same element from the same high energy level to different low energy levels. Used to calculate the conversion factor in the conversion factor method.
1.64 Homologous lines A group of spectral lines emitted by the same element with the same or similar excitation potential, or excited to the same high energy level and transitioned to different low energy levels. Characteristic curve of the emulsion used to make photographic plates. 1.65 Spectral-lineintensity Radiant power of spectral line within unit solid angle. It can be measured by photographic emulsion or photoelectric receiver, or estimated by visual observation. Spectral-line intensity is the basis of spectral age determination analysis. In actual work, it is not necessary to measure the absolute intensity of spectral lines, only the relative intensity is measured. 1. 66 Relative intelsity of line pair relative intelsity f line pair the ratio of the intensities of two spectral lines woven into a line pair. 1.67 Intensity ratio of line pair intensity ratio of linc pair See relative intensity of line pair.
1. 68 Concentration index concentration index The concentration of an element when the intensity of the analysis line and the internal standard line is equal. 1.69 Cyanogenhand
GB9259—88
In emission spectral analysis, due to the use of carbon or stone electrodes or the sample itself contains carbon, during the emission process, carbon combines with nitrogen in the atmosphere to form cyanide, and the cyanide molecules are emitted to emit a band spectrum, called rat band. In the ultraviolet and visible spectral regions, the stronger cyanide bands are at 351.0~359.0nm, 374.0~388.5nm and 410.0~421.6nm. 1.70 Spectral line interference Spectral line interference is the phenomenon that the spectral line of another element overlaps or partially overlaps with the analytical line or internal standard line of the measured element. 1.71. Matrix
One or more main components of the sample, 7.72 Matrix effect
The change of the matrix element content or existence state in the sample affects the evaporation, excitation, ionization and other processes of the measured element, thereby changing the intensity of the analytical line or the relative intensity of the analytical line pair, third element third element
The element present in the sample in addition to the matrix (internal standard) and the measured component. Interelement effect (thirdelement effect) 1.743
The phenomenon that the presence of the third element in the sample causes the intensity of the spectral line of the analytical element to change, thereby affecting the accuracy of the analysis result. 1.75 Analytical gap analyticalgap
The area between the two electrodes that excites the sample and emits radiation energy for spectral analysis. The size of the analytical gap can affect the process of the sample entering the gap and the emission of the spectrum.
1.76 Electrode process Under the action of the excitation light source, a very complex physical and chemical process occurs on (in) the electrode. There must be physical processes such as chemical reactions and phase changes between the components in the sample and the electrode material, between the sample and the electrode and the surrounding atmosphere, and between the sample and the added additives.
1.77 Prearc curve (prespark curve) The curve that represents the change of the relative intensity of the analytical line pair over time. When performing quantitative spectral analysis, the prearc time and the spark time are determined according to the prearc curve to obtain a stable relative intensity of the line pair. 1.78 prearc (prespark) period The period from the moment the light source is turned on to the start of exposure. Exposure is usually started after the intensity ratio of the line pairs to be analyzed has reached a stable level. 1.79 combustion curve combustion curve A curve showing the variation of the intensity (or blackness) of the spectral lines emitted by the component elements of the sample as it burns in the electric field with time. 1.80 evaporation curve volatility curve See combustion curve.
intensity vs time curve 1.81
See combustion curve.
moving-plate study moving-plate study The spectrograph dark box moves vertically or "jumps" continuously during the entire combustion time of the sample to record the variation of the intensity of the spectral lines emitted by the component elements of the sample or the volatility with time during the combustion process. 1.83 order of volatility If the sample contains multiple elements or compounds, they will enter the vapor cloud in sequence according to their different boiling points during the arcing, forming a certain order, namely the volatility order.
1.84 Fractional distillation The phenomenon that the elements in the carbon arc evaporate into the analysis gap at different times, also known as fractional evaporation effect or selective evaporation. By selecting different times for irradiation, spectra of different elements can be obtained, so as to achieve the purpose of separating different elements or impurities from the matrix. 1.85 Additives
Substances added to the sample for a certain purpose. 1.86 Diluent
GB 9259—88
A substance added to the sample, mainly to increase the amount of the test or reduce its concentration for easy processing, and also to reduce the matrix effect.
1.87 Spectroscopic carrier A substance used in emission spectroscopy analysis. After being added to the sample, it can promote the evaporation of the sample into the analysis gap or strengthen the fractionation effect. Spectral carriers mainly include hydride carriers and halide carriers. 1.88 Spectroscopic buffer A substance added to the sample in spectrochemical analysis. Because its presence can minimize the influence of one or several elements on the intensity of the spectral lines of other elements,
1.89 Volatilizer
A substance added to a sample to increase the volatility of the sample or some of its components 1.90
Devolatilizer
A substance added to a sample to reduce the volatility of the sample or some of its components. Its effect is opposite to that of a volatile agent. 1.91
Analysis
The determination of the properties or liquidity of the components or composition of a sample. Determination
The process of determining the properties, composition or concentration of a sample through an experiment. Trace analysis
The analysis of the content of the measured component in a sample at the PPm to ppb level. 1.94 Microanalysis
The analysis of a sample size of about 1 mg.
1.95 Concentration
The amount of a substance contained in a unit sample. The unit of concentration must be clearly stated, such as weight percentage, PP, etc. 1.96 ppm (parts per million) Paris per million A relative concentration expression method used in trace analysis, equal to one part per million, i.e. 10-10%. For trace impurities in a solution, it is more accurate to express it in μg/mL than in ppm. 1.97 ppb (parts per billion) Parts per billion A relative concentration expression method used in trace analysis, equal to one part per billion, i.e. 10-10%. 1. 98 less than (--) less than
In spectrochemical analysis, a way of describing the analysis result, indicating that its value is less than the specified concentration or mass value after the symbol.
1. 99 Detection limit (DL) refers to the concentration or mass corresponding to the minimum net signal in a sample that can be detected with reasonable precision under a given analytical method. 1. 100 Not detected (ND) A method of expressing the results of spectrochemical analysis. It means that although a certain method has been used to find the existence of a certain substance, the result proves that the concentration of the substance is less than the detection limit of this method. 1.101 Sensitivity sensitivity
The ratio of the change in the content of the measured element in the test partner to the change in the corresponding measured signal. In spectral analysis, concentration sensitivity can be expressed by the differential formula (and), the higher the sensitivity, the greater the slope of the working curve. d(AS)
1.102 Spectral purity specpure
When analyzing by spectral separation method, a class of pure substances in which no (or very few) impurity element spectral lines appear in the spectrum. There is no strict regulation on the purity of spectral purity. 1.103 electronic pure
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A method of expressing the purity of high-purity materials. The impurity content in this type of material is extremely low, so that it does not have a negative impact on the performance of electronic products. At present, there is no strict regulation on the purity of electronic pure. blank test blanktest
A test conducted under exactly the same conditions and steps as the analysis of the sample without adding the sample or the measured element. 1. 105 blank value blank value
The additional value of the measurement result introduced by reagents, instruments, environment, etc. In trace analysis, the blank value must be controlled to a minimum.
1.106 multi-element simultaneous determination qualitatively and quantitatively determine multiple elements using only one analytical method. Only methods whose excitation source can simultaneously generate analytical information of multiple elements can essentially meet the conditions for multi-element simultaneous determination. 1. 707 multiclement sequential determination When the excitation source can produce analytical information of multiple elements at the same time, a sequential scanning photometer is used to complete the determination of multiple elements one by one in the order of wavelength.
2 Excitation source
2.1 Light source light source
An object that can emit electromagnetic radiation within a certain wavelength range. In spectral analysis, the light source refers to the luminous body generated when the sample is excited. The generator used to excite the sample is generally called the excitation light source or the light source excitation light source. 2.2 Electric discharge
The passage of electric current in a gas is called discharge. In emission spectral analysis, an excitation source is used to make gas or steam emit light to produce various types of discharges. 2.3 Flame flame
A stable, continuously flowing hot gas mixture whose heat comes from the strong and irreversible exothermic reaction between the fuel and the oxidant. It can be used as an excitation source for emission spectral analysis. 2.4 Flame emission spectrum Ilame enigsion spectrum The spectrum obtained by using flame as the excitation source. 2.5 Premix burner
A mixer in which the combustion gas and the oxidant gas are mixed before reaching the combustion area. 2.6 Flame spectrometry analysis Flame spectroscopy analysis Emission spectroscopy, atomic absorption spectroscopy and fluorescence spectroscopy analysis methods that use flame as an excitation source or atomizer are collectively referred to as flame spectroscopy analysis.
2.7 Flame phatomeric analysis Flame phatomeric analysis A branch of emission spectroscopy analysis. The sample is sprayed into the flame in the form of a solution, and its atoms and molecules are heated and excited to emit light in the flame. The atomic characteristic spectral lines or molecular spectral bands are separated by filters and analyzed by photoelectric devices. 2.8 Flame spectrophotometry Flame spectroscopy analysis in which the spectral element uses a prism or a grating monochromator. 2.9 Nebulizer
In atomic absorption, emission and fluorescence spectroscopy analysis, a device that converts the sample solution into an aerosol, which can form a catalytic burner with the burner.
2.10 Arc discharge
A discharge phenomenon between two electrodes maintained by gas ionization at a certain voltage. Its characteristic is that the spectrum emitted by suspended atoms is the main spectral line. According to different classification methods, arc discharge is divided into DC arc, AC arc, high voltage arc, low voltage arc, continuous arc and intermittent arc discharge.
2.11 Arc spectrum
The spectrum obtained by using arc as the excitation light source, GB9259—88
2.12 DC arc generator is a commonly used excitation source for spectrum analysis. The sample electrode and the ballast resistor are connected in series to the DC power supply. After ignition by a certain method, a DC arc discharge is generated between the electrodes. This discharge has a descending excellent safety characteristic curve. As the current increases, the arc voltage decreases instead. The excitation temperature of the DC arc is suitable for the spectral excitation of most elements. The high temperature of the anode spot is conducive to the evaporation of refractory materials. The electrodes have positive and negative polarities. The samples can be excited with different polarities according to different analysis requirements, and the fractionation effect is significant. 2.13 Anode spot anoriepat
When the DC arc discharges, the extremely bright spot appears on the anode surface. Cathode spot cathodespot
When the DC arc is evacuated, the bright spot appears on the cathode surface. 2. 15 AC arc generator ahternanning current arc generator A commonly used excitation source for spectral analysis. Usually a 220V low-voltage AC arc generator is used, which has two circuits, one is a low-voltage feeder circuit. The AC is added to the gap between the analysis electrodes. The other is a high-frequency ignition circuit, which sends a low-power spark to the gap between the analysis electrodes, and discharges and ignites the arc during each half cycle of the AC. 2.16 Thermal pinch effect Thermal pinch effect When a low-temperature airflow flows around the arc column, the volume of the arc column shrinks. As a result of the arc volume contraction, the arc column current density increases, thereby increasing the excitation temperature. 2.17 Magnetic pinch effect The phenomenon that the arc column volume contracts when an electromagnetic field is formed around the arc column. As a result of the arc volume contraction, the arc column current density increases, thereby increasing the excitation temperature.
2.18 Electrode
In emission spectrum analysis, any of the two endpoints during which discharge occurs. 2.19 Electrode stand
A stand used to support and adjust the sample electrode and auxiliary electrode in emission spectrum analysis. 2.20 Excitation condition In the excitation source of emission spectrum analysis, all conditions that affect the evaporation and emission of the sample and thus the spectral emission are collectively referred to as excitation conditions. Excitation conditions are the key factors in emission spectrum analysis and must be selected through experiments. 2.21 Rectified arc
The electric current obtained by connecting a rectifier circuit to a low-voltage AC arc circuit to achieve half-wave rectification. This arc current is unidirectional and the discharge has a pulse nature.
2.22 High voltage alternating current arc An arc produced under the conditions of voltage of 2 000~5 000 V, current of 1~5 A, and electrode gap of 0.1~1 mm. Due to the high voltage, it can ignite itself after each half-width discharge, and no ignition circuit is required. 2.23 Interrupted arcs interrupted are
A circuit that uses a mechanical interrupter or an electronic pulse circuit to create an arc. The arc discharge is intermittent, and the parameters that represent its intermittent performance are the interruption ratio and the interruption frequency.
2.24 Sparks spark
A series of oscillating discharges caused by high voltage charging a capacitor. At the moment of breaking through the analysis gap or auxiliary gap, it has a relatively high instantaneous current. Each discharge relies on the high voltage to break through itself. When the gap voltage is not enough to maintain the discharge, the spark goes out. 2.25 Spark spectrum
Spectrum obtained by using spark discharge as the excitation source. 2.26 Spark generator GB 9259--88
A generator specially designed to obtain the spark discharge surface commonly used in spectral analysis. Feussner spark generator 2.27
A spark generator commonly used in spectral analysis. A rotating interrupter driven by a synchronous motor is connected in series in the discharge circuit of the capacitor to control the spark discharge. The discharge always occurs at a fixed phase of each half cycle of the power supply voltage. It is required that the capacitor be charged to the highest voltage before the breakdown, which has nothing to do with the analysis gap. 2.28 Raiski spark generator A spark generator commonly used in spectral analysis. A tungsten discharge gap is connected in series in the capacitor discharge circuit as the control gap, and a large resistor is connected in parallel to the analysis gap. The discharge of this generator is not affected by the instability of the power supply voltage, but the air humidity and the oxide film on the electrode surface will affect the discharge.
2.29Air interrupted spark generatorThe circuit is similar to the Raglan spark generator. It uses high-speed airflow to blow away the ions in the control gap, and uses ultraviolet light generated by a mercury lamp to irradiate the control gap to keep the gas in it ionized to a certain extent, ensuring that the breakdown voltage of the control gap is constant and achieving a high degree of discharge stability.
Electronically controlled spark generatorelectronically controlled spark generator2.30
A spark generator that uses an electric circuit to control the discharge of the electric circuit. Rectified high voltage sparkrectifiedhighvoltage apark2.31
In the circuit, the middle end of the secondary of the high voltage transformer is grounded, and the two output ends charge four capacitors respectively through the rectifier tube, and then discharge in sequence in the analysis gap through the synchronous interrupter. The obtained high voltage spark has a single-ended nature. 2.32 Low voltage capacitor discharge uses low voltage (220~10COV) and large capacitor (tens of microfarads) to obtain the discharge energy. It needs to be ignited by low power high cheek sparks. Various discharge forms from arc to spark can be obtained. When the discharge has the nature of sparks, it is usually called low voltage sparks. 2.33 High repetition rate source increases the discharge frequency of the spark source from 50 times per second to several times per second, shortening the pre-combustion and light time required for analysis, which can further improve the speed of rapid analysis.
2.34 Gas discharge tube gas dischargetube is a tube that seals the gaseous sample into a glass or quartz tube and makes it discharge and emit light. The discharge forms in the tube include glow discharge and high-frequency discharge, which are used for spectral analysis of mixed gases or impurities in gases. 2.35 High-frequency discharge is a discharge generated in a low-pressure gas discharge tube under the action of a high-frequency generator ranging from several thousand hertz to hundreds of megahertz, also known as high-frequency electrodeless discharge. It is used for gas spectral analysis and is also suitable for the determination of volatile solid samples and difficult-to-excite elements. 2.36 Glow discharge glowdischarge
Low-pressure gas discharge A type of vacuum discharge lamp. A flat electrode is sealed at each end of the glass tube, and a gas with a pressure of about 1.3×10°Pa or less is filled in. A DC voltage of several hundred volts is applied to the electrodes, and a photodischarge is generated in the tube. It is mainly used as an excitation source for gas spectral analysis. 2.37 Vacuum spark vacuum spark || tt || The spark discharge obtained when the gas pressure is extremely low. It can excite spectral lines with high excitation potential. 2.38 Grimm discharge lamp (Grimm discharge lamp) A new type of spectral analysis excitation source. It is a special configuration of low-pressure gas discharge. Its anode has a hollow chamber and a protruding tube end, with a water-cooled annular The cathode surrounds the protruding end of the anode, and the sample is closely attached to the cathode to form the bottom of the cathode. A carrier gas with a strength of 67 to 2700 Pa is filled in. When a high voltage is applied between the two electrodes, discharge begins. The current is selected within a few to a hundred amperes. The cathode sample is shot into the discharge plasma and emits light due to the collision of electrons and the second type of ions. 2.39 Grimm discharge spectroscopy analysis Grimm discharge spectroscopy analysis is a spectroscopy analysis method that uses a Grimm discharge lamp as an excitation source. The characteristics are: extremely stable luminescence, little influence of the third element, ability to determine difficult-to-excite elements, sharp spectrum lines, and easy replacement of samples. Suitable For principal component analysis, coating surface and non-metallic element determination. The disadvantage is that the detection limit is high.
GB9259—88
2.40 Hollow cathode discharge tube hollwcathodedischagetubc A special configuration of low-pressure gas glow effect tube. The cathode is made into a hollow column, with inert gas as carrier gas, pressure 13~130Pa, and the discharge current is selected in the range of 10 to 2000mA as needed. The sample is analyzed on the inner wall of the hollow cathode or at the bottom of the cavity. The conductor can be directly made into a hollow cathode. During discharge, the radiation generated by the gas ion capsule exiting the cathode causes the sample to enter the discharge area and be emitted. 2.41 Hollow cathode discharge spectroscopic analysis hollow cathode discharge spectroscopic analysis is a spectroscopic analysis method using a hollow cathode discharge tube as an excitation source. Features Low detection limit, stable excitation, and sharp spectral lines. Suitable for trace element determination, difficult to excite element determination, gas analysis and isotope analysis. 2.42 Microwave electrode-less discharge tube A quartz discharge tube is placed in the resonant cavity of a microwave generator, and the gas or metal vapor in the tube is excited to emit light under the action of the electromagnetic field. This type of discharge tube is called a microwave electrodeless discharge tube. It can be used to analyze gases, halogens, volatile elements, etc. 2.43 Plasma source plasma source usually refers specifically to newly developed plasma discharge light sources such as DC arc plasma jet, inductively coupled high-frequency isoproton torch, and microwave plasma torch.
2.44 Plasma jet plasma jet
That is, DC plasma jet. It is referred to as LCP. There is a DC arc discharge of tens to hundreds of amperes between the anode and the annular cathode, and hydrogen or nitrogen is introduced along the axis. Due to heat absorption and electromagnetic contraction effects, the arc plasma is compressed and ejected from the center of the annular cathode to form a plasma jet with a temperature of several thousand to more than 10,000 degrees. At present, it has been improved to a three-pole inverted "Y-shaped structure. The sample is introduced by solution spray method or powder blowing method.
2.45 Inductively coupled high frequency plasma torch is an important new light source for emission spectroscopy analysis, referred to as ICP. It uses a high-frequency generator with a power of several watts and a frequency of tens of megahertz. The electric energy of the injection bottle is coupled to the quartz torch tube through an induction coil wound by a copper tube. In the air flow, a micro-electric spark hole is burned to produce an induction torch, and the sample aerosol is sprayed into it for excitation. It is characterized by a very low detection limit, an excitation temperature of up to 10000K, good precision (coefficient of variation can be as small as 0.3%), a linear range of analysis of 4 to 5 orders of magnitude, and a small vapor effect. 2.46 Skin effect skin effect
The gas that is fully or partially charged in the plasma state can shield the external electromagnetic field, so that the induced discharge current is confined to a thin annular layer near the wall of the discharger at the edge of the plasma, which is called the skin effect. 2.47 Skin depth
The thickness at which the discharge current drops from its maximum value to 1/e (e is the base of the natural logarithm, i.e. 2.718) is defined as the skin depth. Inductively coupled microwave plasma torch2.48
MIP for short. The plasma torch is generated in a quartz tube with a diameter of mm in a microwave resonant cavity, with a power of 25 to 200 W and a common frequency of 2 450 MHz.
2.49 Capacitively coupled high frequency plasma torch Torch is referred to as P. Generally, the energy is supplied by a tube oscillator and transmitted to the pointed electrode that constitutes one pole of the capacitor, so that a high field strength is generated at the tip. When the surrounding gas is ionized, a discharge torch is formed with a particle rate below 300 MHz. 2.50 Capacitively coupled microwave plasma torch Torch is abbreviated as CMP. Microwaves are supplied by a magnetron, transmitted to a tuning cavity through a waveguide, and then coupled to a coaxial tube, and a discharge torch is formed at the tip of the electrode. The power is generally between several hundred watts and several kilowatts, and the frequency is above 300MHz, and 2450MHz is commonly used. 2.51 Laser laser
is also called a photon amplifier. Under the action of light, electricity or chemical reactions, the ions, atoms or molecules contained in some substances are radiated and transition to a metastable state in a non-radiative form, achieving a particle number inversion, that is, the high-energy level particles are more than the low-energy level particles, and an oscillation process of stimulated radiation is generated in the resonant cavity to form a laser. The device that generates laser is called a laser. The laser consists of a laser material, a resonant cavity, a pulsed xenon lamp, a focusing cavity and a power supply circuit. GB9259—88
2.52 Laser micro-spectral analysis lasermicro-probespectrochemical analysis uses a focused laser beam to vaporize the micro-area surface of the sample, and uses auxiliary high-voltage spark discharge to excite the sample vapor for spectral analysis.
3 Spectrometers and other equipment
3. ↑ Spectroscopic laboratory A laboratory equipped with excitation sources, spectrometers, spectrometers, microphotometers, computers and other instruments and equipment to perform spectral analysis on various samples. It is required to have conditions such as anti-dew, moisture-proof, dust-proof, anti-corrosion, and ventilation. Photoelectric spectrometers also require constant temperature and humidity. 3.2 SpectrometerbZxz.net
An instrument that uses dispersion elements and optical systems to separate and arrange light radiation according to wavelengths, and uses appropriate receivers to receive radiation of different wavelengths. The spectrometers used for emission spectral analysis include spectroscopes, spectrographs, and photoelectric direct-reading spectrometers (light meters) according to the different ways of receiving spectral line intensities.
3.3 Spectrograph
spectrograph
An optical instrument with an entrance slit and a dispersion device, which records the spectrum by photographic method. 3.4 Monochromator
A device that can separate a series of monochromatic radiations from a beam of polychromatic radiation with an exit slit. 3.5 Polychromator
A device that can separate a series of monochromatic radiations from a beam of polychromatic radiation with multiple exit slits. 3.6 Nominal wavelength One of the parameters that represents the characteristics of the instrument. The wavelength data marked by the manufacturer after calculation or actual measurement. 3.7 Slit
A very narrow rectangular and arc-shaped hole in the spectrometer. After the light from the light source is projected to the slit, each spectral line obtained by the spectrometer after the light is split is the image of the slit. There are three types of slits: fixed, single-sided adjustable, and double-sided adjustable. 3.8 Entrance slit
The slit installed at the front of the optical system of the spectrometer. The light beam of the light source enters the spectroscopic system of the spectrometer through the slit. Slit image method
A method of focusing the light beam of the white light source onto the entrance slit of the spectrometer with a focusing lens to obtain the real image of the light source. 3.10 Exit slit
A rectangular hole used in the spectrometer to separate harmonic lines of different wavelengths. 3.11 Shutter
A mechanism that introduces light into the optical device at a fixed time. 3.12 Hartmann diaphragmA piece of metal placed in front of the entrance slit with notches of different positions and shapes. Different parts of the slit are intercepted through the notches, so that the captured spectrum falls on different positions of the photosensitive plate without displacement, so as to make qualitative analysis. 3.13 Optical axis
The straight line connecting the center of curvature of the lens or reflector surface in an optical system. 3.14 Collimation
An operation to control a beam of radiation so that it is as close to parallel as possible. 3.15 Collimator
An optical component in a harmonic spectrometer that collimates the light from the incident slit into a parallel beam and then projects it onto the dispersive element. 13.16 Callimator
See Collimator.
3.17 Collimator
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