The wavelengths of maximum absorption and emission of anthracene in Figure 17-22 are approximately 357 and 402 nm. Molar absorptivities at these wavelengths are εex 9.0 × 10³M^-1 cm^-1 and εem = 5 × 10¹ M^-1 cm^-1. Consider a fluorescence experiment in Figure 17-21 with cell dimensions b₁ = 0.30 cm, b₂ = 0.40 cm, and b₃ = 0.5 cm. Calculate the relative fluorescence intensity with Equation 17-12 as a function of concentration over the range 10^-8 to 10^-3 M. Explain the shape of the curve. Up to approximately what concentration is fluorescence proportional to concentration (within 5%)? Is the calibration range in Figure 17-23 sensible?

Figure 17-21

Figure 17-22

Figure 17-23

Equation 17-12

Transcribed Image Text:

Many wavelengths One wavelength Sample cell Light Excitation source monochromator b, b2 Luminescence at many wavelengths Emission monochromator Po Po One em wavelength Entrance slit Detector Exit slit