Absorption synthetic conjugated polymers

Figure 3.5 Absorption spectra of synthetic conjugated polymers. For chemical structures, see Chart 3.2. Adapted with permission from Ref [5] 2002, Springer Verlag.

LDMS is particularly well suited for the analysis of porphyrins.35-39 The heme molecule—a 22 rc-electron conjugated protoporphyrin system (Figure 8.1)—is an efficient photo-absorber in the visible and near UV (with an absorption maximum—the Soret band—near 400nm). This feature, concurrently with its low ionization potential, warrants that direct LDMS will possess extremely low limits for heme detection. The uses of IR or UV LDMS for structural characterization of natural porphyrins and their metabolites, synthetic monomeric porphyrins (e.g., used in photodynamic therapy), porphyrin polymers, and multimeric arrays, have been well documented.41148 In addition fast atom bombardment MS has been used to characterize purified hemozoin, isolated from the spleens and livers of Plasmodium yoelii infected mice.49... 

The IR absorption spectrm of synthetic polymers is generally simple. In Figure 17.22 we illustrate the polystyrene spectrum, which is fairly representative of aromatic hydrogen polymers. The polystyrene spectrum s three IR bands appear sharply in the spectrum without ambiguity at 2850,1603, and 906 cm . The bands above 3000 cm are due to unsaturated C H stretching vibrations. The stretching vibration of conjugated C=C appears around 1600 cm . The presence of the 760-and 700-cm bands are attributed to C H deformations. Monosubstitution is confirmed by the pattern of weak bands from 2000 to 1600 cm . Atactic polystyrene has bands at 670,620,565 (shoulder), and 536 cm. Isotactic polystyrene does not have any absorption from 550 to 500 cm or at 670 cm . The... 

---