Photometry visibility analysis

Analytical applications have been found for all parts of the electromagnetic spectrum ranging from microwaves through visible radiation to gamma (y) rays (Table 1). The emission and absorption of electromagnetic radiation are specific to atomic and molecular processes and provide the basis for sensitive and rapid methods of analysis. There are two general analytical approaches. In one, the sample is the source of the radiation in the other, there is an external source and the absorption or scattering of radiation by the sample is measured. Emission from the sample may be spontaneous, as in radioactive decay, or stimulated by thermal or other means, as in flame photometry and fluorimetry. Both approaches can be used to provide qualitative and quantitative information about the atoms present in, or the molecular structure of, the sample. 

Colorimetry and photometry are the next spectral optical analysis methods. Both the methods measure absorbed light as was shown for infrared spectroscopy. However, for both these analyses, light with shorter wavelength is used. Colorimetry uses light with wavelength of only the visible spectral area and photometry uses the visible light, ultraviolet, and in some case, infrared area. A comparison of the different spectral areas is shown in Figure 2.47. 

There are a number of other methods, spectroscopic as infra-red (IR), ultraviolet-visible (UV-Vis), which allow the evaluation of the ability of the Ca complex formation. Not all of them are suitable in every case. We have decided to explore the flame photometry and conductometric titration since the NMR changes were too small to perform the correct analysis. 

An unequivocable identification of an unknown component is unlikely by the chromatographic process alone. Not the least of the reasons for this is the need for the comparisons of standards, thereby assuming reasonable prior assurance of the possible identity of the unknown. Certainly the more discrete pieces of information obtainable concerning an unknown compound, the easier it will be to obtain confident identification. Microchemical tests such as functional group classification, boiling point, elemental analysis, and derivative information, as well as infrared spectroscopy, coulometry, flame photometry, and ultraviolet (UV)-visible spectroscopy are also useful aids when used in conjunction with gas chromatographic data. 

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