Quantitative Analysis of Salicylates by Visible Spectroscopy

innovation The purpose of this lab was to learn how to use a spectrophotometer to measure the marrow of light absorbed by different soaking ups of salicylic acid, compare those immersions to our unacknowledged assay and to use the selective information collected to compile a graph show the levels of absorbance of the different preoccupancys. Methods and materials In this lab we used a spectrophotometer, a trial run tube filled with water to be used as a blank, six test tubes with different duckings of salicylic acid ranging from 0 mg/dL to 5 mg/dL and one test tube with an un cognize concentration of salicylic acid.We set the spectrophotometer to a wavelength of 540 nm. We adjusted the transmittance to 0%. next we placed the test tube with the water into the spectrophotometer and adjusted the transmittance control to 100%. We removed the test tube containing the water and replaced it with the first concentration of 0 mg/dL. We recorded the absorbance and retell the test for a join of 5 readings. We did this for each concentration. We then calculated the average of each concentrations absorbance readings and plotted the averages onto the graph.Once we had gathered the data for our known concentrations we then repeated the procedure for our unknown concentration. We again took the average and plotted that on the absorbance turn to pin down the concentration of the unknown. Observations and Data Calibration Standard Absorbance variation 1 Absorbance Reading 2 Absorbance Reading 3 Absorbance Reading 4 Absorbance Reading 5 AverageAbsorbance Reading 0 mg/dL 0. 007 0. 010 0. 007 0. 005 0. 006 0. 07 0. 5 mg/dL 0. 032 0. 036 0. 037 0. 041 0. 038 0. 037 1. 5 mg/dL 0. 098 0. 100 0. 098 0. 099 0. 096 0. 098 2. 5 mg/dL 0. 150 0. 149 0. 153 0. 154 0. 150 0. 151 3. 5 mg/dL 0. 234 0. 239 0. 237 0. 250 0. 229 0. 238 5. 0 mg/dL 0. 286 0. 287 0. 288 0. 292 0. 291 0. 289 Unknown A 0. 241 0. 238 0. 239 0. 241 0. 241 0. 239 Based on the data from the known concentra tions I found our unknown to be a concentration of 3. mg/dL. Conclusions We used a spectrophotometer to determine the concentration curve for the known samples then used both the spectrophotometer and the concentration curve to determine the concentration of the unknown sample. This technique can be used by toxicologists to determine the amount of drugs in a persons blood. This can be helpful if there was an overdose or if the district attorney require to know the concentration of drugs in someones system.