Physical-chemical and ecotoxic evaluation of different deep eutectic solvents for green analytical applications.

The search for new analytical methods is a latent reality in the so-called green analytical chemistry area, which aims at correlating analytical demands to environmental issues. Among the approaches used, it is possible to highlight green solvents as substitutes to the dangerous and conventional organic solvents as the most prominent alternative for this purpose. In the last few years, the amount of research focused on the usage of deep eutectic solvents (DESs) has been growing as an alternative to these issues. Thus, this work aimed to investigate the main physical-chemical and ecotoxical properties of seven different DESs. The results showed that DESs' evaluated properties are influenced by the chemical structure of their precursors, which may regulate DESs' viscosity, superficial tension, and antagonistic action against vegetable tissues and microbial cells. The constatations pointed here introduce a new perspective about the conscious usage of DESs on a green analytical point of view.

Near infrared reflectance spectrometry classification of cigarettes using the successive projections algorithm for variable selection.

This paper proposes a methodology for cigarette classification employing Near Infrared Reflectance spectrometry and variable selection. For this purpose, the Successive Projections Algorithm (SPA) is employed to choose an appropriate subset of wavenumbers for a Linear Discriminant Analysis (LDA) model. The proposed methodology is applied to a set of 210 cigarettes of four different brands. For comparison, Soft Independent Modelling of Class Analogy (SIMCA) is also employed for full-spectrum classification. The resulting SPA-LDA model successfully classified all test samples with respect to their brands using only two wavenumbers (5058 and 4903 cm(-1)). In contrast, the SIMCA models were not able to achieve 100% of classification accuracy, regardless of the significance level adopted for the F-test. The results obtained in this investigation suggest that the proposed methodology is a promising alternative for assessment of cigarette authenticity.