CHEM357 Chapter Notes - Chapter 13-14: Fourier-Transform Infrared Spectroscopy, Chymotrypsin, Data Analysis

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Overview: absorbance, fluorescence, circular dichroism, nmr spectroscopy. Many biological molecules can absorb light in the ultra-violet-visible range of the electromagnetic spectrum. Chromophoric molecules generally contain multiple bonds; electrons in these bonds can be excited to nonbonding or antibonding orbitals by absorption of a photon of light. The colour of the chromophoric molecule is complementary to the wavelength of the absorbed light. Absorbance, a, is described by beer-lambert law: = extinction coefficient, l = pathlength, c = concentration. The absorbance of independent species is additive. To determine the concentrations of n independent species, measure the solution absorbance at n different wavelengths. For a solution containing 2 components, m and n, with known , measurement of solution absorbance at 2 wavelengths, 1 and 2, can be used to determine the concentrations of m and. A sample of the hormone glucagon is hydrolyzed to its constituent amino acids, and the uv absorbance of the hydrolysate is measured at 240 nm and 280nm.