R & D Resourses

The UV-Vis spectrophotometer works on the principle of absorption of light by a sample at different wavelengths in the UV (190-400 nm) and visible (400-800 nm) regions of the electromagnetic spectrum. Light Source:A deuterium lamp is used for the UV region (190–400 nm), and a tungsten filament lamp is used for the visible region (400–800 nm). These lamps emit light across the respective wavelength ranges. Monochromator:The light from the source passes through a monochromator (usually a prism or diffraction grating), which splits the light into its constituent wavelengths. The monochromator selects the required wavelength to pass through the sample. Sample Interaction:The selected light passes through the sample. If the sample contains absorbing molecules, a certain amount of light will be absorbed based on the chemical composition and concentration of the sample. The amount of absorption depends on the intensity of light at that particular wavelength. Detector:After the light passes through the sample, a photodetector (usually a photodiode or photomultiplier tube) detects the intensity of the transmitted light. The detector then converts the light into an electrical signal. Data Analysis:The instrument measures the absorbance (A) of the sample at the selected wavelength using Beer-Lamberts Law: ??=log(??0??) A=log( II 0) where:A = Absorbance, I0 = Intensity of incident light (before passing through the sample), I = Intensity of transmitted light (after passing through the sample). The data is displayed as absorbance or transmittance versus wavelength, creating a spectrum.