[16p-2C-1~10] 4.2 Bio- and Medical Photonics

▲ [16p-2C-8] Optical Properties of Oleoresin with Capsaicin in Visible Window Using Diffuse Reflectance Spectroscopy

〇(DC)Lopez Manuel Abraham¹, Baez Jose Javier¹, Castro Jorge¹ (1.Ntl. Inst. of Astrophysics Optics and Electronics)

Keywords:Diffuse Reflectance Spectroscopy,Optical Proerties,Kubelka-Munk

Kubelka-Munk reemission function is used to calculate optical properties of an oleoresin with capsaicin in the visible window. To get these optical properties different methods are used, one of this is to use diffuse reflectance spectroscopy and Nonlinear Least Squares to fit the diffuse reflectance in function of concentration. A simple setup is proposed to get optical properties like absorption and scattering using reemission function from the mentioned theory. 30 samples in groups of ten were prepared diluting capsaicin with pure ethanol to get solutions at 0.1% to 1%. OceanOptics^© spectrometer was used, the model USB-4000. A bifurcated fiber is plugged to spectrometer and the other extreme to the light source to carry the information from the sample to the spectrometer. The light source has 360nm-2000nm bandwidth. First was put the setup in blank, a quartz cuvette with pure ethanol between Spectralon^© standard and testing probe was measured, and then each sample with diluted capsaicin, later, all concentrations were measured ten times. The results shows a weak signals from 500nm to 600nm, then from 600nm the signals starts to increases, for concentrations from 0.1% this has a strong signal but when the concentration increase this takes lower values for 1% concentration, this oleoresin has a particular behavior when is highly diluted is possible to see a weak minimum reflectance signal between 660nm and 670nm but this low value increase when the concentration is 1%. Due the reemission function model was used, for analyze the data a Non Linear Least Squares statistical method was used to fit them. The results show that the correlation coefficients are close to 1 and are acceptable for trust in the recovered factors. Optical information was possible get, like scattering and molar extinction coefficient from oleoresin with capsaicin in the visible window using a simple setup applying diffuse reflectance spectroscopy.