d)
Use the toggle to switch the Spec-20 from Transmittance (T) to Absorbance (A).
The Spec-20 is now set to read the absorbance of your sample.
DO NOT change
any settings!!!
Clean the cuvette containing Solution #1 with a Kimwipe to
remove all prints. Remove the cuvette with water, and replace it with the cuvette
containing Solution #1.
e)
Record the absorbance on the display. If it reads a small negative number, record
an absorbance of 0 for that reading.
4)
Repeat steps a-e for a wavelength of 425 nm. Record the absorbance value for
Solution #1 at this new wavelength, then repeat steps a-e to obtain absorbance
readings at wavelengths every 25 nm between 400 and 600 nm.
5)
Repeat steps a-e in 5-nm increments for three wavelengths above and three
wavelengths below the maximum. For example, if you found the highest absorbance
at 450 nm, repeat steps a-e for wavelengths of 455, 460, 465, 445, 440, and 435 nm.
6)
The wavelength that gives the maximum absorbance for these readings is the
λ
max
to
use for Part III below.
7)
Have your instructor approve your chosen
λ
max
before you continue to Part III.
