ABSTRACT
With an increase in the excitation wavelength (λ0) from 488 nm to 785 nm, there is a substantial decrease in signal observed. e best normal Raman spectrum was obtained with λ0 = 488 nm. No spectrum was generated using the FT-Raman, even aer mixing the pigment with KBr in order to minimize sample heating and reduce uorescence. e spectrum obtained with SERS corresponds to the peaks observed with the normal Raman spectrum at λ0 = 488 nm. ere was not any apparent signal enhancement observed going from normal Raman to SERS at this excitation wavelength. e FT-IR/ATR spectrum generated a number of well-resolved peaks; the peaks characteristic of quinacridones are apparent with the series of peaks in the region of 1630-1550 cm−1, and the peaks located at 1472 cm−1 and 1335 cm−1. With regard to UV/Vis, the absorbance maximum of Pigment Red 122 was 302.0 nm, likely a bathochromic shi that resulted from the solvent system (concentrated H2SO4). is is supported by the change in color observed (red to a bluish-red, or purple shade). Correlation can be made between the
experimental data and reported data for PR 122 (Scherrer et al., 2009; Schulte et al., 2008) (Figure 10.1).
