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A simple sensitive method for nonspecific recognition of armagnac, cognac, whiskey, and ethanol/water mixture was developed by using photoluminescence (PL) of carbon nanoparticles (NPs). The carbon NPs were synthesized from the mixture of urea and anhydrous citric acid, followed by few annealing processes to achieve the full effect by solvothermal carbonization. PL features of carbon NPs depend on the alcohol environments in which the NPs are dispersed. PL/PL excitation maps of the alcoholic beverages were mathematically treated, and a final principal component analysis diagram allows visualization of different clusters corresponding to each beverage. The optimal measurement conditions (concentration of NPs in colloidal solution and excitation wavelength) were defined to ensure a reliable recognition level.

In this study, we report soft and solvothermal methods for synthesis of zinc oxide nanoparticles (ZnO NPs). Both methods involve a precursor and are carried out at the middle low-temperature regime. The effect of different solvents on the ZnO NPs properties was studied. The nonlinear optical (NLO) response of the NPs was analyzed by the self-action of picosecond laser pulses at 1064 nm and by second harmonic generation (SHG) of a femtosecond laser pulses pump at 800 nm. The luminescence was studied within UV-visible ranges. It was shown that the NLO response efficiency significantly depends on the solvent. The obtained SHG efficiency of small (~2 nm) ZnO NPs is comparable to the one obtained for large (~150 nm) commercial ZnO NPs. The observed results are important for the application of the ZnO NPs in biolabeling.Electronic supplementary materialThe online version of this article (doi:10.1186/s11671-017-1934-y) contains supplementary material, which is available to authorized users.

A novel sensing system was designed for pH measurements based on the enhanced and quenched photoluminescence (PL) and UV-Vis absorption of the diluted water solutions of F-, O-, and N-containing carbon nanoparticles (FON-CNPs). These FON-CNPs were solvothermally synthesized, dissolved, ultra-iltrated, and separated by thin-layer chromatography. The total luorine content in them was found to be 1.2-1.5 mmol per gram. Their TGA showed a total weight loss of 52.7% because of the thermal decomposition and detachment of the surface groups and the partial burning of the functionalized shell on the carbon core at temperatures below 1200 °C. TEM and Raman data conirmed the presence of graphitic structures in the carbon core. From the results of ATR FTIR and UV-Vis spectroscopies, we showed that a carbon shell incorporates diferent functional groups covering the carbon core. The surface groups of the carbon shell include carboxyl, phenolic, and carbonyl groups. Heterocyclic N-containing and amino groups and triluoromethyl groups supporting the hydrophobicity were also found. We suggested the possible reasons for the pH responses obtained with the sensing system considering them dependent on the de-protonation of functional groups with pH change.