Analytical Chem istry - DePauw University

642 Analytical Chemistry 2.0Example 10.13To evaluate the method described in Representative Method 10.5, a seriesof external standard was prepared and analyzed, providing the resultsshown in the following table.mg SO 2– 4 /L transmittance0.00 1.0010.00 0.64620.00 0.41730.00 0.26940.00 0.174–logT1.00.80.60.40.20.00 10 20 30 40mg sulfate/LAnalysis of a 100.0-mL sample of a surface water gives a transmittance of0.538. What is the concentration of sulfate in the sample?So l u t i o nLinear regression of -logT versus concentration of SO 4 2– gives a standardizationequation of− =− × − 5mg SOlog T 104 . 10 + 0.0190×LSubstituting the sample’s transmittance into the calibration curve’s equationgives the concentration of sulfate in sample as 14.2 mg SO 4 2– /L.2−4As you review this chapter, try to define akey term in your own words. Check youranswer by clicking on the key term, whichwill take you to the page where it was firstintroduced. Clicking on the key termthere, will bring you back to this page sothat you can continue with another keyterm.10IKey Termsabsorbance absorbance spectrum absorptivityamplitude attenuated total reflectance atomizationbackground correction Beer’s law chemiluminescencechromophore continuum source dark currentdouble-beam effective bandwidth electromagnetic radiationelectromagnetic spectrum emission emission spectrumexcitation spectrum external conversion Fellgett’s advantagefiber-optic probe filter filter photometerfluorescence fluorescent quantum yield fluorimeterfrequency graphite furnace interferograminterferometer internal conversion intersystem crossingionization suppressor Jacquinot’s advantage lifetimeline sourcemethod of continuousvariationsmolar absorptivitymole-ratio method monochromatic monochromatornephelometry nominal wavelength phase angle