Dependence of surface enhanced Raman scattering from Calf thymus DNA on anions

Dependence of surface-enhanced Raman scattering (SERS) from Calf thymus DNA on anions is investigated. With the silver colloid, the bands at 732, 960 and 1333 cm-1 for adenine (A), 1466 cm-1 for deoxyribose, and 1652 cm-1 for the C=O group of thymine (T) are observably enhanced. With the presence of the Cl- or SO^(2-)_(4) anions, the bands at 732 and 1326/1329 cm-1 for the symmetric stretching and skeletal vibrational modes of adenine (A) are dramatically enhanced, and the enhancement effect wit