Spectrometer to Measure the Steady-State Fluorescence Emitted by Liquid and Solid Samples

Abstract

Fluorescence methods are being widely used in the measurement of species concentrations in gases, liquids and solids. Fluorescence is spontaneous emission from atoms or molecules that have been excited by light. Here we report some measurements of steady-state fluorescence emitted by samples of liquids (Antifreeze, detergent, soapy water), solids (colored bond papers) and organic compounds (vegetables and fruits). The measurements were performed with a home made spectrometer from 200 to 800 nm. This consists of an excitation light source, a bifurcate optical fiber probe for high delivery and collection of light, a monochromator with a high sensitivity PMT, a DAQ board, and a lap-top computer. The spectrometer is controlled by a program written in the graphical language G of the LabVIEW 7.1. For purposes of comparison we use two light sources: an UV led (375 nm) and a high luminescence blue led (447 nm).