The A260/A280 ratio for this sample was measured at 1.62. What does this tell you about the purity of your sample?  Group of answer choices: A. this sample is pure B. this sample is somewhat pure, but might be contaminated with a substance that absorbs at 260 C. this sample is contaminated with a substance that absorbs highly at 230 D. this sample is contaminated with a substance that absorbs highly at 280

PRE-LAB QUESTIONS Experiment 121 Complete these questions prior to attending lab. Some of the results will be useful in conducting the experiment, so you should record those results in the appropriate section of the lab as well. 1. In Part A, step 1, you are directed to set up the spectrophotometer for measurement of the FeSCN2+ product ion. a. Based on the spectra given here, what would be an appropriate wavelength for the measurement? Review Appendix I if necessary to again familiarize yourself with the issues related to this decision. b. Briefly explain your choice. 0.5 A 0.4 0.3 Absorbance A Absorbance spectra for Fe³+ and FeSCN²+ 0.2 0.1 0 400 0.02 M Fe³+ (dissolved in HNO3) E121-11 0.000048 M FeSCN²+ 500 600 wavelength (nm) 700 2. In Part A, step 4, you will experimentally determine the value of the molar absorptivity, &, for FeSCN2+ at your selected wavelength. Using the Beer-Lambert law, calculate an approximate value for & based on the spectrum of 0.000048 M FeSCN2+ provided…

Chemistry Instrumental Analysis Class The experiment is OES: Cleaning Validation of removal of pharmaceutical drugs and calibration standards by fluoresence spectroscopy - Why the instrument use two detectors and monochromators? What type of monochromators are used in our instrument? - Do you think that a similar experiment can be prepared for the analysis of naproxen and benzoic acid? Explain.

8