Metal ions sensing properties of some phenylquinoxaline derivatives.

The sensitivity and selectivity properties of three phenylquinoxaline derivatives to different metal ions were investigated by absorption and fluorescence spectroscopy. The absorption and fluorescence responses of the phenylquinoxaline derivatives were examined towards the following metal ions Ag+, Mg2+, Co2+, Ni2+, Cu2+, Zn2+, Cd2+ and Hg2+, in THF solution. All investigated samples exhibit sensitivity and selectivity to Ag+, Co2+ and Cu2+ ions compared to other metal ions (Mn+ = Mg2+, Ni2+, Zn2+, Cd2+ and Hg2+). The gradual addition of Ag+, Co2+ and Cu2+ ions to a Q-Ox sample solution generates new absorption bands (with maxima at 244, 675 and 294 nm, in presence of the Ag+, Co2+ and Cu2+ ions, respectively) while the emission intensities were weakly quenched, except in presence of Ag+ ions, when the emission was almost completely quenched (quenching efficiency at 426 nm, (I0 - I) / I0 × 100% = 91%). Absorption and fluorescence results show the formation of 1:2 metal complexes with Ag+ ions and 1:1 stoichiometry for a complexation between Q-Ox and Co2+ or Cu2+ ions. The following characteristics of these phenylquinoxaline derivatives have been calculated and discussed: the effects of the interfering ions, the binding constants and the detection limit of Ag+, Co2+ and Cu2+ ions.

GiPlot: An interactive cloud-based tool for visualizing and interpreting large spectral data sets.

Latest advances in technology and the growing amount of experimental and business data have increased the number of users accessing on-line tools dedicated to quickly visualize and analyse large data sets. This paper describes the development and functionality of a new interactive cloud computing based plotting tool (GiPlot - Google-based Interactive Plot) easy-to-use for universal data. It has interactive features that facilitate data share and interpretation, and selection of specific data suitable for further uses and detailed studies. It also allows quick and step-by-step visualizations of the impact of various experimental conditions on spectral data sets. For a detailed illustration of the features of this interactive plotting tool, we have used mainly spectral data for a given solute dissolved in mixed solvents and for changes in the absorption and/or fluorescence properties of a solute solution in the presence of different chemical stimuli. The most important features and functionalities of this new tool have also been summarized and suggestively highlighted through a short collection of video tutorials containing many examples, developed by the authors of this paper as a support for both the tool and this paper.