Allelochemicals are safer, more selective and more active alternatives than synthetic agrochemicals for weed control. However, the low solubility of these compounds in aqueous media limits their use as agrochemicals. Herein, we propose the application of α-, β- and γ-cyclodextrins to improve the physicochemical properties and biological activities of three sesquiterpene lactones: dehydrocostuslactone, costunolide and (-)-α-santonin. Complexation was achieved by kneading and coprecipitation methods. Aqueous solubility was increased in the range 100-4600% and the solubility-phase diagrams suggested that complex formation had been successful. The results of the PM3 semiempirical calculations were consistent with the experimental results. The activities on etiolated wheat coleoptiles, Standard Target Species and parasitic weeds were improved. Cyclodextrins preserved or enhanced the activity of the three sesquiterpene lactones. Free cyclodextrins did not show significant activity and therefore the enhancement in activity was due to complexation. These results are promising for applications in agrochemical design.

Arsonists usually use an accelerant in order to start or accelerate a fire. The most widely used analytical method to determine the presence of such accelerants consists of a pre-concentration step of the ignitable liquid residues followed by chromatographic analysis. A rapid analytical method based on headspace-mass spectrometry electronic nose (E-Nose) has been developed for the analysis of Ignitable Liquid Residues (ILRs). The working conditions for the E-Nose analytical procedure were optimized by studying different fire debris samples. The optimized experimental variables were related to headspace generation, specifically, incubation temperature and incubation time. The optimal conditions were 115 °C and 10 min for these two parameters. Chemometric tools such as hierarchical cluster analysis (HCA) and linear discriminant analysis (LDA) were applied to the MS data (45–200 m/z) to establish the most suitable spectroscopic signals for the discrimination of several ignitable liquids. The optimized method was applied to a set of fire debris samples. In order to simulate post-burn samples several ignitable liquids (gasoline, diesel, citronella, kerosene, paraffin) were used to ignite different substrates (wood, cotton, cork, paper and paperboard). A full discrimination was obtained on using discriminant analysis. This method reported here can be considered as a green technique for fire debris analyses.

Two optimized methods for ultrasound-assisted extraction were evaluated for the extraction of two types of acai bioactive compounds: Total anthocyanins (TAs) and total phenolic compounds (TPCs). For the extraction optimization, a Box Behnken factorial design of different variables in the following intervals was used: Methanol-water (25%–75%) for solvent composition, temperatures between 10 and 70 °C, amplitude in the range between 30% and 70% of the maximum amplitude −200 W), extraction solvent pH (2–7), the ratio for sample-solvent (0.5 g:10 mL–0.5 g:20 mL), and cycle between 0.2 and 0.7 s. The extraction kinetics were studied using different periods between 5 and 30 min. TA and TPC were analyzed by UHPLC and the Folin–Ciocalteu method, respectively. Optimized conditions for TA were: 51% MeOH in water, 31 °C temperature, pH 6.38, cycle 0.7 s, 65% amplitude, and 0.5 g:10 mL of sample-solvent ratio. Optimized conditions for the TPC were: 49% MeOH in water, 41 °C temperature, pH 6.98, cycle 0.2 s, 30% amplitude, and 0.5 g:10 mL of sample-solvent ratio. Both methods presented a relative standard deviation below 5% in the precision study. The suitability of the methods was tested in real samples. It was confirmed that these methods are feasible for the extraction of the studied bioactive compounds from different açai matrices.

10 11 1 3 h i g h l i g h t s 14 15HS-MS and NIRS allow for gasoline samples discrimination. 16 No solvents are need for the HS-MS analyses nor for NIRS analyses, no wastes are produced. 17 HS-MS method produced similar or better results than NIRS for the discrimination among gasoline samples. 18 2 0 mass spectrometry 30 Research octane number 31 Forensic sciences 32 3 3 a b s t r a c t 34 Headspace mass spectrometry and near infrared spectroscopy in combination with chemometric tools, 35 including hierarchical cluster analysis and linear discriminant analysis, have been used for the classifica-36 tion of gasoline according to the research octane number. Volatile components were studied by head-37 space mass spectrometry whereas the whole gasoline samples were studied by near infrared 38 spectroscopy. Sample pretreatment was not required for either analysis. A set of 60 samples belonging 39 to two different research octane numbers (95# and 98#) was analyzed by both techniques. The best 40 results were obtained on using linear discriminant analysis, which allowed a full discrimination of 41 the gasoline samples using only four m/z ratios (46, 59, 95 and 98) in the case of headspace mass 42 spectrometry and three regions (below 1000 nm, 1400-1500 nm and 1600 nm) in the case of near 43 infrared spectroscopy.44