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In general, the components of an atomic absorption spectrometer (AAS) is equal to the spectrometer UV / Vis. Both have a component that consists of a light source, the sample, monochromator, and detector. Analysis of samples is done by measuring the absorbance as a function of the concentration of the standard and using Beer's law to determine porifera the concentration porifera of the unknown sample. Although component-komponenya the same, but the light source and the sample used in the SSA have characteristics very different from those used in molecular spectrometry (eg UV / Vis).
Because atomic absorption bandwidth at around 0001 nm, it is not possible to use a continuous light source such as the molecular porifera spectrometry with the following two main reasons: absorption bands produced by the atoms is much narrower than the bands produced by spectrometry molecules. If continuous light source is used, then the band of radiation is given by the monochromator is much wider than the absorption band, so much radiation that does not have a chance to be absorbed resulting in sensitivity or sensitivity SSA becomes ugly. Because the radiation from the light source is not terabsorpi by atom, then the continuous light source is a very strong need to produce great energy in the wavelength region is very narrow or need to use a detector which is much more sensitive than ordinary photomultiplier detector, but in the practice this is not effective, so do not do.
In general, Beer's law will not be met unless the emission bands narrower than the absorption band. This means that all wavelengths used to detect the sample should be able to be absorbed by the sample. Gambar17.2 porifera shows a comparison of the atomic absorption band and continuous spectrum light source produced by the monochromator. From the figure it can be seen that most of the radiation can not be absorbed due to their wavelengths porifera are not on the local atomic absorption band is very narrow and it can be said that it is very much light is not used or distorted.
This problem can be overcome porifera by Alan Walsh in 1953, using a single light source (line source) as a continuous light source replacement. Most of the single light source used was from a hollow cathode lamp (hollow chatode lamp) that emits atomic emission spectrum of a particular element, such as a lamp used to analyze katodeberongga Zn Zn. Figure 3a and 3b show a single light to overcome the problems described above.
Zn spectrum observed at a wavelength of 213.4 nm before porifera and after transmission through a conventional monochromator. Although the band width of the monochromator is not smaller than before transmission, but the sample is measured to be in the desired wavelength region. By choosing a lamp containing the analyte being measured, then we can know that the wavelength used is equal to the absorption band of the analyte being measured. This means that all of the radiation emitted by the light source can be absorbed by the sample and Beer's law can be used.
By using a single light source, a conventional monochromator porifera can be used to isolate the spectral bands are usually referred to the resonance bands. This tape shows the resonance transition to the ground state atoms of the first transition state, which is usually very sensitive to metal detecting measured.
Cathode lamp shape can be seen in the main picture of this lamp is 17.4.Ciri has a cylindrical hollow cathode made of a certain metal. Tungsten cathode porifera and anode is placed in a sealed glass containing protective inert gas (Ne or Ar) with a pressure of 1-5 torr. This lamp has a potential of 500 V, while the current range between 2-20 mA.
Adapungas filler ionized at the anode, and the ions are accelerated towards the cathode which produces ions bombardment caused atoms to the surface of the metal becomes detached and formed a cloud / atomic population. This process is called the spark atoms (sputtering). Furthermore, this collision caused some excited atoms and then back to the ground porifera state by emitting a spectrum of specific atoms. The spectrum of the gas filler (and other components contained in the cathode) are also emitted. Window or the place where the radiation out of the lamp usually porifera made of silica that can use wavelength
Articles News Biochemical Chemistry Chemical Analysis Chemical Physics Inorganic Chemistry Environmental Chemistry Food Chemistry Materials porifera Appropriate Technology Tips and Info Scholarship Opinion Editor Career Training Event IChO IChO Problem Problem porifera Problem OSN Materials Chemistry Chemical Material Leaders Ask the Expert Learning Periodic Table Organic Reactions porifera
In general, the components of an atomic absorption spectrometer (AAS) is equal to the spectrometer UV / Vis. Both have a component that consists of a light source, the sample, monochromator, and detector. Analysis of samples is done by measuring the absorbance as a function of the concentration of the standard and using Beer's law to determine porifera the concentration porifera of the unknown sample. Although component-komponenya the same, but the light source and the sample used in the SSA have characteristics very different from those used in molecular spectrometry (eg UV / Vis).
Because atomic absorption bandwidth at around 0001 nm, it is not possible to use a continuous light source such as the molecular porifera spectrometry with the following two main reasons: absorption bands produced by the atoms is much narrower than the bands produced by spectrometry molecules. If continuous light source is used, then the band of radiation is given by the monochromator is much wider than the absorption band, so much radiation that does not have a chance to be absorbed resulting in sensitivity or sensitivity SSA becomes ugly. Because the radiation from the light source is not terabsorpi by atom, then the continuous light source is a very strong need to produce great energy in the wavelength region is very narrow or need to use a detector which is much more sensitive than ordinary photomultiplier detector, but in the practice this is not effective, so do not do.
In general, Beer's law will not be met unless the emission bands narrower than the absorption band. This means that all wavelengths used to detect the sample should be able to be absorbed by the sample. Gambar17.2 porifera shows a comparison of the atomic absorption band and continuous spectrum light source produced by the monochromator. From the figure it can be seen that most of the radiation can not be absorbed due to their wavelengths porifera are not on the local atomic absorption band is very narrow and it can be said that it is very much light is not used or distorted.
This problem can be overcome porifera by Alan Walsh in 1953, using a single light source (line source) as a continuous light source replacement. Most of the single light source used was from a hollow cathode lamp (hollow chatode lamp) that emits atomic emission spectrum of a particular element, such as a lamp used to analyze katodeberongga Zn Zn. Figure 3a and 3b show a single light to overcome the problems described above.
Zn spectrum observed at a wavelength of 213.4 nm before porifera and after transmission through a conventional monochromator. Although the band width of the monochromator is not smaller than before transmission, but the sample is measured to be in the desired wavelength region. By choosing a lamp containing the analyte being measured, then we can know that the wavelength used is equal to the absorption band of the analyte being measured. This means that all of the radiation emitted by the light source can be absorbed by the sample and Beer's law can be used.
By using a single light source, a conventional monochromator porifera can be used to isolate the spectral bands are usually referred to the resonance bands. This tape shows the resonance transition to the ground state atoms of the first transition state, which is usually very sensitive to metal detecting measured.
Cathode lamp shape can be seen in the main picture of this lamp is 17.4.Ciri has a cylindrical hollow cathode made of a certain metal. Tungsten cathode porifera and anode is placed in a sealed glass containing protective inert gas (Ne or Ar) with a pressure of 1-5 torr. This lamp has a potential of 500 V, while the current range between 2-20 mA.
Adapungas filler ionized at the anode, and the ions are accelerated towards the cathode which produces ions bombardment caused atoms to the surface of the metal becomes detached and formed a cloud / atomic population. This process is called the spark atoms (sputtering). Furthermore, this collision caused some excited atoms and then back to the ground porifera state by emitting a spectrum of specific atoms. The spectrum of the gas filler (and other components contained in the cathode) are also emitted. Window or the place where the radiation out of the lamp usually porifera made of silica that can use wavelength
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