In my undergraduate thesis, I evaluated the behaviour of modular molecular fluorescence spectrometer. I focused on its use, so I tested its capabilities and working characteristics on concrete solution samples. Firstly, with the help of literature and data about characteristic wavelengths of emission and excitation maxima, I searched and selected five substances that are fluorescent and are accessible in ordinary analytical laboratory. The criteria for choosing were mainly that their maxima appear in wider range of spectrum. So, I chose riboflavin, fluorescein, benzoic, folic and salicylic acid as sample solutions. After choosing the substances, I have sought for information on the preparation of solutions and measurement conditions in the literature. Later I prepared solutions of riboflavin in 5% acetic acid, fluorescein in 0,1% ammonia, benzoic acid in 0,01 mol/L HCl, salicylic acid in a solution of acetic acid and folic acid in a solution of phosphate buffer and 0,1 mol/L aqueous solution of ammonia. For the selected substances, I first recorded absorption spectra on UV-VIS spectrometer, after that emission and excitation spectra on molecular fluorescence spectrometer. Then, following the same procedures, I prepared the solutions and recorded spectra on modular system, which I could later compare with those obtained on conventional instruments. On all of them, I tested the behaviour in wider range of changing the parameters. With the components used, I managed to determine the emission maximum on modular system for two substances that emit light above 500 nm (riboflavin and fluorescein). For the rest, this was not possible. But on the other side, I could determine absorption maxima for all model substances. When comparing wavelengths of the maximum between different instruments, I found out that there is no big difference and same when comparing the results with literature. But the comparison of intensities is difficult due to different design of instruments.
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