Perkin-Elmer Lambda38 UV/VIS 8/2005S.O.P for analysis of unknown using Beer’s LawYou will need to know the approximate wavelength of maximum absorbance of your sample. 1. Switch on power – right rear toggle switch.2. Switch on appropriate lamp – UV or VIS.Switches on lower right front panel.3. Enter wavelength you want to scan, GOTO to enter wavelength into center display.Use (c/e) to clear display.Absorbance is displayed in right display.Use mode key to change readout mode from absorbance to % transmittance.4. Fill two polystyrene cuvettes with D.I water. Use polystyrene cuvettes. Insert cuvettes in sample holders. Handle cuvettes by opaque side, place clear side of cuvettes in light path and close cover.5. Observe reading on display, if reading is not zero press auto zero.6. If wavelength setting drifts press GOTO λ to return to your original scan wavelength. Having zeroed the instrument and entered the scan wavelength you are now ready to run a sample.7. Rinse out cuvettes. Place sample in front cuvette, place reference in rear cuvette, close lid.8. Record absorbance (ABS) or percent transmittance (%T) as required.Note:Numbers below (nm) display are scan speeds these values are not critical but do not scan in (T) mode.When creating calibration curve be sure to force Excel to go through (X=0, Y=0)The (SAFM) button is used to store preset values – do not use this feature.The left-most display should read (C) indicating no values are stored in memory.If you feel your readings are in error refer to the operations manual and run the wavelength calibration procedure.Example using potassium permanganate.A. Insert sample cell in front cell, reference in rear cell. B. Hold cell on the opaque side. The clear side faces the light path. C. Fill both cells with D.I water, observe test results. If different, enter AUTO ZERO. If λ drifts hit GOTO λ to return to λ.C. Insert solvent to test in front slot. Record ABS or % T. Numbers below readouts are scan speeds, refer to manual for more info. For Beers law this is not critical.SAFM = Store preset values- not