In UV/VIS (ultraviolet-visible light) spectroscopy, light absorption as a function of various wavelengths gives data about electronic transitions within a solution . The electronic transitions involve exciting an electron from one principle quantum state to another by the absorption of energy . A change in absorption energy gives information on molecular characteristics of a solution. UV/VIS was used in this experiment to determine the concentration of Isoprenaline Hydrochloride in an unknown solution and to compare the experimentally determined and theoretical …show more content…
Solution A (NA+ analysis) was prepared by diluting 2.5ml of working stock to 50ml with double distilled water. Solution B (K analysis) was prepared by diluting 25ml of working stock to 50ml with double distilled water. Sodium and potassium ion concentrations were then determined by the use of a flame photometer.
The molar absorptivity value for Isoprenaline experimentally determined was 101.52M-1cm-1, whereas the literature molar absorptivity value was 100M-1cm-1. This shows that the value obtained experimentally was 1.52M-1cm-1 higher than the literature value.
As the concentration of Isoprenaline increased, the absorptions levels also increased, for example the absorbance for 0.002% w/v was 0.177λ, whereas the absorbance for 0.004% w/v was 0.407λ. This indicates that the absorbance of Isoprenaline increased by 0.23λ. The Isoprenaline absorption also increased between the concentrations 0.006% w/v, which had an absorbance level of 0.629λ and 0.008% w/v, which had an absorbance of 0.844λ, by 0.215λ. There was a significant increase of the Isoprenaline absorption spectrum between the lowest concentration and the highest concentrations of Isoprenaline. The absorbance of the lowest concentration (0.002% w/v) was 0.117λ, while the absorbance of the highest concentration (0.01% w/v) was 0.996λ, so the absorbance spectrum of Isoprenaline increased by 0.819λ. The increase in the absorption spectrum illustrates that as the concentrations of Isoprenaline rises, the more Isoprenaline particles the uv/vis light absorbs (see figure