This experiment delves into spectophotometry principles, a fundamental analytical chemistry
technique. According to Eyring (2014), spectrophotometry is a technique used to measure the
intensity of light absorbed or transmitted by a substance as a function of wavelength. This
light absorption is governed by Beer’s Law, which states that a solution's absorbance (A) is
directly proportional to the concentration of the absorbing species and the path length of the
sample. According to Edinburgh Instruments (2023), Beer’s Law is expressed as A= εcl,
where A is the absorbance, ε is the molar absorptivity, c is the concentration of the absorbing
species and l is the path length of the sample.
The key terms involved in spectrophotometry include absorption and absorbance. According
to Molecular Devices (2023), absorption refers to the process by which light energy is
absorbed by a substance, causing electrons to transition to higher energy levels. Absorbance,
on the other hand, is a measure of the amount of light absorbed by a solution and is directly
related to the concentration of the absorbing species.
, To obtain the maximum absorbance of the analyte, the concept of analytical wavelength is
used, which is a specific wavelength chosen at which the absorbance of the analyte is
measured to ensure optimal sensitivity and accuracy in the analysis.
To quantify the relation between absorbance and concentration, a calibration curve is
constructed. This curve is generated by measuring the absorbance of standard solutions with
known concentrations across a range of wavelengths. A linear relationship can be established
by plotting absorbance versus concentration, allowing for the determination of unknown
concentrations based on their absorbance values.
This experiment uses spectrophotometry and Beer’s Law to quantitatively determine the
concentration of an analyte in solution by measuring its absorbance at a specific wavelength.
By understanding these fundamental principles, effective analysis and interpretation can help
achieve analytical goals.
The below table provides information on the data used in the procedure and calculation of the
concentration for unknown solutions.
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