Fluorescence spectroscopy: from fundamentals to the influence of instrumental parameters for analysis of organic dyes and inorganic nanoparticles.

Fluorescence spectroscopy is an extremely sensitive analytical technique that has been widely used to elucidate problems that require low detection limits. Although fluorescence spectroscopy is widespread in industry and academia, there is a lack of teaching materials demonstrating its basic principles, as well as the influence of instrumental parameters involved in the technique, which limit its correct use and the full potential of it. For this reason, this work aims to explore the principles of fluorescence spectroscopy and correlate them in function of different instrumental variables to carry out a fluorescence experiment. The spectrofluorometer parameters such as the excitation wavelength, excitation and emission slits, step, integration time, detection geometry as well as concentration of the samples were varied to illustrate how the best resulting spectra can be registered free of artifacts. To do so, two organic dyes with structured vibronic bands (pyrene) and another with unstructured bands (rhodamine 6G) were used. Another study carried out involved the use of 3D spectra, excitation/emission spectra, of cadmium telluride (CdTe) quantum dots. In this case, it was possible to show the excitation spectrum of nanomaterials, collecting emissions at different wavelengths, as well as analyzing the particle size distribution.