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The concentration of sites is given by dividing the total number of sites (S 0) covering the whole surface by the area of the adsorbent (a): [ S 0 ] = S 0 / a . {\displaystyle [S_{0}]=S_{0}/a.} We can then calculate the concentration of all sites by summing the concentration of free sites [ S ] and occupied sites:
Variable pathlength absorption spectroscopy uses a determined slope to calculate concentration. As stated above this is a product of the molar absorptivity and the concentration. Since the actual absorbance value is taken at many data points at equal intervals, background subtraction is generally unnecessary.
Absorbance is defined as "the logarithm of the ratio of incident to transmitted radiant power through a sample (excluding the effects on cell walls)". [1] Alternatively, for samples which scatter light, absorbance may be defined as "the negative logarithm of one minus absorptance, as measured on a uniform sample". [2]
The analytical (total) concentration of a reactant R at the i th titration point is given by = + [] + where R 0 is the initial amount of R in the titration vessel, v 0 is the initial volume, [R] is the concentration of R in the burette and v i is the volume added. The burette concentration of a reactant not present in the burette is taken to be ...
The concentration needed to cause this effect is seen to change as the amount of non-volatile matrix changes. So concentration of solid analyte needs to be considered in the preparation of the solution for analysis so that signal from "hidden" analyte is not missed. [17] To choose the matrix for each solid analyte, three criteria must be ...
The increase of absorbance at 595 nm is proportional to the amount of bound dye, and thus to the amount (concentration) of protein present in the sample. [ 6 ] Unlike other protein assays, the Bradford protein assay is less susceptible to interference by various chemical compounds such as sodium, potassium or even carbohydrates like sucrose ...
In particular, the pH of a solution can be predicted when the analytical concentration and pK a values of all acids and bases are known; conversely, it is possible to calculate the equilibrium concentration of the acids and bases in solution when the pH is known. These calculations find application in many different areas of chemistry, biology ...
Hyperchromicity is the increase of absorbance (optical density) of a material. The most famous example is the hyperchromicity of DNA that occurs when the DNA duplex is denatured. [1] The UV absorption is increased when the two single DNA strands are being separated, either by heat or by addition of denaturant or by increasing the pH level.