A miniaturized solid-contact potentiometric multisensor platform for determination of ionic profiles in human saliva

This paper describes a miniaturized multisensor platform (MP-ISES) consisting of electrodes: a reference one (RE) and ion-selective electrodes (ISEs) for monitoring Na⁺, K⁺, Ca²⁺, Mg²⁺, Cl⁻, and SCN⁻ ions and pH in human saliva. Gold electrode surface was modified by deposition of two layers: electrosynthesized PEDOT:PSS forming an intermediate layer, and ion-selective membrane. The developed ISEs were characterized by a wide linear range and sensitivity consistent with the Nernst model. The entire MP-ISEs are characterized by satisfactory metrological parameters demonstrating their applicability in biomedical research, in particular in measurements concerning determination of ionic profiles of saliva. Saliva samples of 18 volunteers aged from 20 to 26 participating in a month experiment had been daily collected and investigated using the MP-ISEs assigned individually to each person. Personalized profiles of ions (ionograms) in saliva, such as Na⁺, K⁺, Ca²⁺, Mg²⁺, Cl⁻, SCN⁻, and H⁺, were obtained.

     

Synthesis and characterization of new porphyrin/4-quinolone conjugates

New porphyrin/4-quinolone conjugates were synthesized from the Suzuki-Miyaura coupling reaction of a β-borylated porphyrin with bromo-4-quinolones containing N-ethyl and N-d-ribofuranosyl substituents. The use of electrospray ionization tandem mass spectrometry showed important information about the fragmentation pathways of the new compounds. It was possible to distinguish between those compounds with the porphyrin moiety linked at the 6-position of the quinolone unit from their 7-substituted isomers. The new compounds showed to be good singlet oxygen generators.     

New synthetic methods for 2,3-diarylacridin-9(10H)-one and (E)-2-aryl-4-styrylfuro[3,2-c]quinoline derivatives

Two new synthetic methodologies for 2,3-diarylacridin-9(10H)-ones were developed. The first one involves the Heck reaction of (E)-3-iodo-2-styrylquinolin-4(1H)-ones with styrenes, leading to (E,E)-2,3-distyrylquinolin-4(1H)-ones, which when heated at high temperatures cyclize in two different ways. Electrocyclization and further in situ oxidation leads to 2,3-diarylacridin-9(10H)-ones, while tautomerization, cyclization by nucleophilic addition and further in situ oxidation produces (E)-2-aryl-4-styrylfuro[3,2-c]quinolines as the main compound. The second method gives only 2,3-diaryl-10-methylacridin-9(10H)-ones and involves the Heck reaction of (E)-3-iodo-1-methyl-2-styrylquinolin-4(1H)-ones and styrenes, leading to (E,E)-1-methyl-2,3-distyrylquinolin-4(1H)-ones, which when heated at high temperatures cyclize through electrocyclization and oxidation processes affording the expected compounds. The structures of all new compounds were established by extensive NMR studies.     

Recent advances on the use of active anodes in environmental electrochemistry

Active anodes, especially those consisting of metal mixed oxides (MMOs) containing Ru and/or Ir oxides, have been applied in the treatment of wastewater, especially when chloride ions are present. Their characteristics continuously drive the study of applications of these materials, be they in the degradation of different organic molecules, the preparation of new electrode materials and in the association of various processes to increase pollutant removal. Thus, this brief review aims to present some of the recent advances in the application of active anode materials in environmental electrochemistry. Focussing on the 2018–2020 period, it is possible to note many applied studies, using commercially available materials, covering a wide range of target pollutants. Still other studies aim to modify the catalyst surfaces to increase the mineralization capacity, and the use of these anodes in the production of free chlorine species to mediate indirect organic reduction is observed.     

Kinetics of the hydrogen abstraction R?OH + H → R?O• + H2 reaction class

This paper presents an application of the reaction class transition state theory (RC‐TST) to predict thermal rate constants for the hydrogen abstraction R? OH + H → R? O^? + H₂ reaction class, where R is an alkyl group. We have derived all parameters for the RC‐TST method for this reaction class from rate constants of 19 representative reactions, coupling with linear energy relationships (LERs) and the barrier height grouping (BHG) approach. Error analyses indicate that the RC‐TST/LER, where only reaction energy is needed, and RC‐TST/BHG, where no other information is needed, can predict rate constants for any reaction in this reaction class with satisfactory accuracy for combustion modeling. Specifically for this reaction class, the RC‐TST/LER method has less than 25% systematic errors in the predicted rate constants, whereas the RC‐TST/BHG method has less than 35% error when compared to explicit rate calculations. © 2010 Wiley Periodicals, Inc. Int J Chem Kinet 42: 414–429, 2010