Determination of Isoprenaline Hydrochloride Concentration Using Ultra Violet/ Visible Spectroscopy and Quantification of Sodium and Potassium Using Flame Spectroscopy
Introduction
In UV/VIS (ultraviolet-visible light) spectroscopy, light absorption as a function of various wavelengths gives data about electronic transitions within a solution [1]. The electronic transitions involve exciting an electron from one principle quantum state to another by the absorption of energy [2]. 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 molar extinction coefficient. Flame photometry measures the intensity of the light emitted when a metal is introduced into a propane air flame (1900-2000°C). The wavelength of the colour indicates what the element is and the intensity of the colour emitted by the flame, indicates how much of the element is present [3]. The heat of the flame dissociates bonds and excites the atoms. The excited atoms return to ground state and emit photons of characteristic wavelengths. Group 1 metals such as Li, Na, and K are analysed with flame photometry, however, Ca2+ and Mg2+, which are group 2 metals, are not analysed using flame photometry because they have two valence electrons in their outer shell which means high temperatures are needed to excite them [4]. Flame photometry was used in this experiment to quantify sodium (Na+) and potassium (k+) in a balanced salt solution. Methods Uv/vis 0.1% w/v stock solution of Isoprenaline hydrochloride in water was used to prepare 50ml of 0.01% w/l Isoprenaline solution. A quartz cuvette and a spectrophotometer were used to record the absorption spectrum of 0.01% Isoprenaline hydrochloride solution from 350-240nm to determine λmax which was 279.5λ. Four 25ml standard solutions each containing Isoprenaline hydrochloride in a range of 0-0.01% w/v was prepared. The absorbance was then collected at λmax. a graph of absorption against concentration was then plotted and the molar absorptivity of Isoprenaline hydrochloride …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.
Discussion
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
Introduction
In UV/VIS (ultraviolet-visible light) spectroscopy, light absorption as a function of various wavelengths gives data about electronic transitions within a solution [1]. The electronic transitions involve exciting an electron from one principle quantum state to another by the absorption of energy [2]. 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 molar extinction coefficient. Flame photometry measures the intensity of the light emitted when a metal is introduced into a propane air flame (1900-2000°C). The wavelength of the colour indicates what the element is and the intensity of the colour emitted by the flame, indicates how much of the element is present [3]. The heat of the flame dissociates bonds and excites the atoms. The excited atoms return to ground state and emit photons of characteristic wavelengths. Group 1 metals such as Li, Na, and K are analysed with flame photometry, however, Ca2+ and Mg2+, which are group 2 metals, are not analysed using flame photometry because they have two valence electrons in their outer shell which means high temperatures are needed to excite them [4]. Flame photometry was used in this experiment to quantify sodium (Na+) and potassium (k+) in a balanced salt solution. Methods Uv/vis 0.1% w/v stock solution of Isoprenaline hydrochloride in water was used to prepare 50ml of 0.01% w/l Isoprenaline solution. A quartz cuvette and a spectrophotometer were used to record the absorption spectrum of 0.01% Isoprenaline hydrochloride solution from 350-240nm to determine λmax which was 279.5λ. Four 25ml standard solutions each containing Isoprenaline hydrochloride in a range of 0-0.01% w/v was prepared. The absorbance was then collected at λmax. a graph of absorption against concentration was then plotted and the molar absorptivity of Isoprenaline hydrochloride …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.
Discussion
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