# Radiation Concentration Of Unknown Samples Using A Uv Visible Spectrometer

1276 WordsDec 17, 20156 Pages
etermination of iodine concentration of Unknown samples using a UV-Visible Spectrophotometer. Abstract: The purpose of this experiment is to use UV/Visible Spectrophotometer to determine the concentration on three unknown samples of iodine (A, B and C), this is done by measuring the absorbance of different known concentration of iodine using a UV/Visible Spectrophotometer and plotting a calibration curve of Absorbance Vs Concentration (as shown in Fig 4). This is used to find the concentration of the unknown samples as the absorbance was measured using a UV Spectrophotometer. The wavelength used to measure the absorbance is 287.20 nm and the method number used was ‘40’. The concentration of Samples A, B and C are 1.48*10-4M, 1.03*10-4M…show more content…
When a light set at a specific wavelength enters the cuvette which contains the solution that need to be tested, some of the incident light (I0) is absorbed by the solution, and the rest of the light which leaves the solution (the transmitted light I) is detected, the amount of light absorbed depends on the concentration of the solution. The amount of light that goes into the solution and the amount of light that leaves the solution gives a value of the absorbance (A) of the solution which can be calculated by using the equation: (A= -log (I/I0)). This equation assumes that all the incident light is either transmitted or absorbed, therefore, reflection or scattering are insignificant.  The quantity of light absorbed is inversely proportional to the logarithm of the amount of light absorbed by the substance. The amount of light absorbed by a substance is directly proportional to the concentration of the substance (As the concentration increases, the absorbance also increases provided that the wavelength is constant).  A=lc  Where is the substance and wavelength specific absorption coefficient, I is the length the light travels through the sample and c is the concentration of the sample.  To comprehend the theory behind how a spectrophotometer works, an understanding of the relationship between energy and light must be required. Light contains tiny packs