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原子发射光谱仪工作原理
www2138com官网:0 发布时间:2019-07-15
 

  原子发射光谱仪(AES),是利用原子或离子在一定条件下受激而发射的特征光谱来研究物质化学组成的分析方法。根据激发机理不同,原子发射光谱有3种类型:①原子的核外光学电子在受热能和电能激

  Atomic emission spectrometry (AES) is an analytical method to study the  chemical composition of the material by using the characteristic spectrum of  atom or ion under certain conditions. According to the different excitation  mechanism, there are 3 types of atomic emission spectra: the nuclear external  optical electrons in the atom and the

  发而发射的光谱,通常所称的原子发射光谱法是指以电弧、电火花和电火焰(如ICP等)为激发光源来得到原子光谱的分析方法。以化学火焰为激发光源来得到原子发射光谱的,专称为火焰光度法。②原子核外光学电子受到光能激发而发射的光谱,称为原子荧光(见原子荧光光谱分析)。③原子受到X射线光子或其他微观粒子激发使内层电子电离而出现空穴,较外层的电子跃迁到空穴,同时产生次级X射线即X射线荧光(见X射线荧光光谱分析)。在通常的情况下,原子处于基态。基态原子受到激发跃迁到能量较高的激发态。激发态原子是不稳定的,平均寿命为10-10~10-8秒。随后激发原子就要跃迁回到低能态或基态,同时释放出多余的能量,如果以辐射的形式释放能量,该能量就是释放光子的能量。因为原子核外电子能量是量子化的,因此伴随电子跃迁而释放的光子能量就等于电子发生跃迁的两能级的能量差  ,式中h为普朗克常数;c为光速;ν和λ分别为发射谱线的特征频率和特征波长。

  The atomic emission spectrometry, commonly referred to as the atomic  emission spectrometry, is an analytical method to obtain atomic spectra by means  of arc, electric spark, and electric flame (e.g., ICP, etc.). The flame is used  as the excitation source to get the atomic emission spectrum, which is called  the flame photometric method. Atomic fluorescence spectroscopy, atomic  fluorescence spectrometry, atomic fluorescence (see atomic fluorescence  spectrometry). The atoms are X ray photons or other micro particle excitation to  the inner electron ionization and a hole, the outer layer of the electronic  transitions into the hole, at the same time to produce secondary X ray or X ray  fluorescence (see X - ray fluorescence analysis). In the usual case, atoms are  in the ground state. The ground state atom is excited by the excited transition  to the higher energy. Excited state atoms are unstable, the average life  expectancy of 10-10 ~ 10-8 seconds. Then the excited atom is going to jump back  to the low energy state or the ground state, and at the same time release the  excess energy. If the energy is released in the form of radiation, the energy is  released by the energy of the photon. Because the atom energy is quantized, so  with the electronic transitions and the photon energy release is equal to the  electronic transitions of the two level energy difference, h for the Planck  constant; C light; V and lambda respectively transmit characteristic frequency  and characteristic wavelength spectrum.

  根据谱线的特征频率和特征波长可以进行定性分析。常用的光谱定性分析方法有铁光谱比较法和标准试样光谱比较法。

  According to the characteristic frequency and the characteristic wavelength  of the spectral line can be analyzed qualitatively. Comparison of analytical  methods for spectral analysis and standard sample spectra comparison.

  原子发射光谱的谱线强度I与试样中被测组分的浓度c成正比。据此可以进行光谱定量分析。光谱定量分析所依据的基本关系式是I=acb,式中b是自吸取系数,α为比例系数。为了补偿因实验条件波动而引起的谱线强度变化,通常用分析线和内标线强度比对元素含量的关系来进行光谱定量分析,称为内标法。常用的定量分析方法是标准曲线法和标准加入法。

  The spectral line intensity of the atomic emission spectrum is proportional  to the concentration of I in the sample. The concentration of C is proportional  to the concentration of the component. Based on the above analysis, the spectral  quantitative analysis. Spectral quantitative analysis is based on the basic  relationship is I=acb, B is the self absorption coefficient, alpha as the ratio  of. In order to compensate for the experimental conditions of fluctuations  caused by the spectral intensity variation, usually with analysis of the  relationship between the line and the line intensity ratio of elements for  quantitative analysis, known as internal standard method. Standard curve method  and standard addition method are commonly used in the quantitative analysis.

  原子发射光谱分析的优点是:①灵敏度高。许多元素绝对灵敏度为10-11~10-13克。②选择性好。许多化学性质相近而用化学方法难以分别测定的元素如铌和钽、锆和铪、稀土元素,其光谱性质有较大差异,用原子发射光谱法则容易进行各元素的单独测定。③分析速度快。可进行多元素同时测定。④试样消耗少(毫克级)。适用于微量样品和痕量无机物组分分析,广泛用于金属、矿石、合金、和各种材料的分析检验。

  The advantages of atomic emission spectrum analysis are as follows: 1. The  absolute sensitivity of many elements is 10-11 ~ 10-13 G. Good selectivity. Many  similar chemical properties were measured by chemical method to elements such as  tantalum, niobium and zirconium and hafnium, rare earth elements, its spectral  properties are quite different, easy to separate determination of elements by  atomic emission spectrum law. Analysis speed. Simultaneous determination of  multiple elements. The little sample consumption (mg). Suitable for the analysis  of trace samples and trace inorganic compounds, which are widely used in the  analysis of metals, ores, alloys, and various materials.


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