Perpustakaan Digital ITB

Porphyrin is a heterocyclic macromolecules which has an important role in biological processes of living things, such as photosynthesis, electron transfer, and activation of oxygen. Porphyrin has many applications such as photocatalyst, photodynamic therapy for cancer treatment, photosensitizer in solar cells, and other applications. Due to many important roles of porphyrin, a good characterization method is needed to identify its structure and properties, for example Raman spectroscopy. However, in Raman spectroscopy, fluoresence signal of porphyrin can interfere Raman signal. There are some techniques to increase the intensity of Raman signals, such as Surface-Enhanced Resonance Raman Scattering (SERRS) and Drop Coating Deposition Raman (DCDR) spectroscopy. In this study, DCDR technique was performed on a gold metal surface in tetraphenylporphyrin (TPP) characterization. Here, optimum conditions was obtained by varying temperature, heating time, concentration, and type of substrate. We found that 40 minutes heating at 100°C of substrate and 1×10-4 M analyte give the highest signal. This optimum condition of measurement was applied to characterize tetra(3-methylphenyl)porphyrin, tetra(4- methylphenyl)porphyrin, tetra(3-carboxyphenyl)porphyrin, and tetra(4-carboxyphenyl) porphyrin. Then substrate effect on Raman signal analysis was carried out using TPP. We found that gold give the highest Raman intensity among the four studied substrate i.e. aluminium foil, tantalum plate, Indium Tin Oxide (ITO) glass, and gold.