Characterization of an ultraviolet irradiation chamber to monitor molecular photo degradation by Raman spectroscopy

Author(s)

Borio, Viviane Gadret ^[1] ; Fernandes, Adjaci Uchoa ^[1] ; Silveira, Jr., Landulfo ^[1]

Affiliation

^[1] Univ Camilo Castelo Branco UNICASTELO, Inst Biomed Engn, BR-12247016 Sao Jose Dos Campos, SP - Brazil

• Document type: Journal article
• Source: Instrumentation Science & Technology; v. 44, n. 2, p. 189-198, MAR 3 2016.
• Web of Science Citations: 2

Abstract

A homemade ultraviolet chamber is reported to induce photochemical changes with characterization by Raman spectroscopy. The equipment has compartments for ultraviolet-A (UV-A) (8 lamps of 8W) and for UV-A+ultraviolet-B (UV-B) irradiation (4 lamps of 26W and 1 lamp of 15W). The irradiance was measured 3, 5, and 10cm from the light sources. The maximum irradiance was obtained at 3cm (UV-A: 2.66mW/cm(2) and UV-A+UV-B: 4.30mW/cm(2)). The chamber internal temperature was stabilized at 30 degrees C after 1hr of operation with an internal relative humidity of approximately 45%. 10% Collagen was irradiated with UV-A at 2.0mW/cm(2) for 3hr with changes in Raman peaks at 1253, 1271, 1453, and 1660cm(-1) indicating changes in conformation. 5% Atenolol was irradiated with UV-A+UV-B at 4.30mW/cm(2) for 8 hours with changes to Raman peaks at 822, 1186, 1206, 1248, and 1618cm(-1). A commercial insect repellent was irradiated with UV-A+UV-B at 4.30mW/cm(2) for 8hr and decreases in Raman intensity were observed at 526, 690, 1003, and 1606cm(-1) due to degradation of N, N-diethyl-m-toluamide. The results demonstrate proper operation of the irradiation chamber with Raman spectroscopic monitoring. (AU)

• FAPESP's process: 09/01788-5 - Dispersive Raman spectroscopy using optical fibers "Raman probe" applied to the diagnosis of neoplasia in the skin and prostate
• Grantee: Landulfo Silveira Junior
• Support Opportunities: Regular Research Grants