E not observed inside the UV-Vis comparison in the fluorescence spectra nones have been not observed within the UV-Vis spectra. Aspectra. A comparison of your fluorescence spectra shows that the derivatives are characterized by the decrease fluorescence and wider shows that the derivatives are characterized by the reduce fluorescence intensityintensity and wider array of emitted wavelengths compared to initialmaterials. Incorporation of addi-of range of emitted wavelengths when compared with initial humic humic materials. Incorporation further hydroquinone centers are certainly not conjugated to the Butenafine site aromatic technique of HA detional hydroquinone centers which which are not conjugated towards the aromatic program of HA decreases conjugation of the derivatives and leads to a rise in the intensity along with a blue creases conjugation in the derivatives and leads to a rise inside the intensity in addition to a blue shift of your fluorescence spectra to the region of shorter wavelengths (42040 nm). In the shift with the fluorescence spectra towards the area of shorter wavelengths (42040 nm). In the similar time, hydroquinone-substituted ones are characterized by a redshift of your spectrum same time, hydroquinone-substituted ones are characterized by a redshift of your spectrum (44050 nm), related with a rise within the aromaticity from the molecular ensemble of (44050 nm), linked with a rise in the aromaticity with the molecular ensemble of FC derivatives. In conjunction with a change in the position of fluorescence, alterations in the shape FC derivatives. In addition to a modify in the position of fluorescence, changes within the shape of your fluorescence band are of excellent diagnostic value for characterizing the structural in the fluorescence band are of good diagnostic importance for characterizing the strucfeatures of HA and FA. In the obtained fluorescence spectra, the following descriptors tural features of HA and FA. In the obtained fluorescence spectra, the following dewere calculated (Table 2). scriptors have been calculated (Table 2). It was found that the SUVA254 value, which characterizes the degree of aromaticity of HS, decreased within the order CHP CHP-HQ CHP-MHQ CHP-PC for HA derivatives. The opposite scenario was observed for FA derivatives modified with hydroquinones: the SUVA254 worth Fenbutatin oxide References enhanced in the order FA = FA-MHQ FA-HQ FA-PC. In accordance with a decrease in E2/E3 value, which can be straight proportional to a size in the molecule, modification brings about an increase in the size of FA molecules. Fluorescence data demonstrate a considerable distinction within the shape of fluorescence spectra of HA and FA derivatives, in particular, in the red-wavelength range of the spectrum, so incorporation of additional hydroquinone- and naphthoquinone-moieties into molecular ensemble of FA and HA leads to a rise inside the Asm350 (asymmetry index) value. This indicates a “blue” shift in intensity (a reduce inside the red wavelength variety) from the derivatives characteristic to low molecular weight hydroquinones and naphthoquinones.Agronomy 2021, 11,9 ofTable 2. Optical descriptors obtained as a result of processing the UV-Vic and fluorescence spectra of your parent HA and FA and their derivatives.Sample CHP CHP-HQ CHP-MHQ CHP-PC CHP-NQ CHP-2OHNQ FA FA-HQ FA-MHQ FA-PC FA-NQ FA-2OHNQ SUVA254, L/mgC cm 0.066 0.063 0.052 0.050 0.065 0.059 0.033 0.038 0.035 0.038 0.039 0.031 E2/E3 2.65 two.54 two.67 2.74 3.44 three.77 6.01 3.45 four.61 4.66 5.31 8.46 E4/E6 3.51 three.26 three.30 2.54 four.25 two.65 2.66 three.90 3.50 four.08 , nm 95 97 101 15.