The present work evaluated the effect on charge transfer in functionalized TiO2 nanostructured systems using different binders. We highlight the conditions required to form self-assembled systems by varying the number of layers, as well as by substituting them for an organic binder, cysteine. Additionally, we study the pH effect of the precursor solution (HAuCl4) on gold nanoparticles (AuNPs) formation. The morphological characterization allowed us to determine the percentage of Au atoms on the surface of the synthesized nanoparticles. Inductively coupled plasma mass spectrometry (ICP-MS) analysis determined the amount of gold deposited on the TiO2 surface, which ranged from 4.56 to 253.00 ng mm-2 depending on the system used. Based on Fourier-transform infrared spectroscopy (FTIR) and Raman analysis, it was possible to propose a photolysis mechanism for AuNP formation in accordance with the change in the binders. The different systems were subjected to hydrogen photogeneration by a water splitting process, resulting in 2.02 µmol cm-2 of hydrogen production for cysteine binder [Cys+HAuCl4-2.7]. There proved to be an excellent synergy between the morphological aspects, crystallinity, and stability of this arrangement.

A method for determining low levels of As and Cd by dispersive liquid-liquid microextraction (DLLME) and inductively coupled plasma mass spectrometry (ICP-MS) was proposed. The following parameters that affect extraction efficiency were investigated: type and volume of extraction solvent (1000 µL acetone), type and volume of dispersive solvent (75 µL carbon tetrachloride), amount of ammonium pyrrolidinedithiocarbamate and sodium diethyldithiocarbamate as chelating agents, sample mass (0.5 g in 10 mL ultrapure water), pH of sample solution (2.0) and number of washing steps (one). Accuracy was evaluated by analytes determination in sugar samples by ICP-MS after digestion by microwave-induced combustion (MIC). No significant difference was observed between results of the proposed DLLME method and MIC in the case of both analytes. Instrument calibration was performed by the standard addition method and good linearity was achieved. Limits of quantification (LOQs) were 0.7 and 0.2 ng g-1 for As and Cd, respectively. The main advantages of this method are relatively high sample mass, low dilution, suitable preconcentration factors and significantly low LOQs (ng g-1 range). When the proposed method was used for determining As and Cd in four sugar samples, their concentrations ranged from 1.13 to 2.95 ng g-1 and from 0.31 to 0.43 ng g-1, respectively.