Two digestion procedures have been tested on nut samples for application in the determination of essential (Cr, Cu, Fe, Mg, Mn, Zn) and non-essential (Al, Ba, Cd, Pb) elements by inductively coupled plasma-optical emission spectrometry (ICP-OES). These included wet digestions with HNO(3)/H(2)SO(4) and HNO(3)/H(2)SO(4)/H(2)O(2). The later one is recommended for better analytes recoveries (relati...

BACKGROUND/PURPOSE Hydrogen sulfide (H2S) is a neuromodulator acting through nitroxyl (HNO) when it reacts with nitric oxide (NO). HNO activates transient receptor potential channels of the ankyrin type 1 (TRPA1) causing release of calcitonin gene-related peptide from primary afferents. Activation of meningeal nociceptors projecting to the human spinal trigeminal nucleus (STN) may lead to heada...

Neste trabalho são propostos métodos analíticos rápidos para a determinação direta de Al, Cu e Fe em água de coco não processada por espectrometria de absorção atômica com atomização eletrotérmica. Para a determinação de Fe, 100 μL das amostras foram diluídos com 1400 μL de solução 0,1% v/v HNO 3 . Alíquotas de 10 μL desta solução foram injetadas no tubo de grafite sem a adição de modificador q...

The excited triplet state of 1-nitronaphthalene, 1NN, ((3)1NN) is able to oxidise nitrite to ˙NO(2), with a second-order rate constant that varies from (3.56 ± 0.11) × 10(8) M(-1) s(-1) (μ±σ) at pH 2.0 to (3.36 ± 0.28) × 10(9) M(-1) s(-1) at pH 6.5. The polychromatic quantum yield of ˙NO(2) photogeneration by 1NN in neutral solution is Φ(˙NO(2))(1NN)≥ (5.7 ± 1.5) × 10(7)× [NO(2)(-)]/{(3.4 ± 0.3...

Mechanisms for the formation of Type I (nitric acid-based) polar stratospheric louds (PSCs) are discussed. If the pre-existing sulfate aerosols are liquid prior to PSC formation, then nitric acid particles (Type Ib) form by HNO 3 dissolution in aqueous H2SO,• solution droplets. This process does not require a nucleation step for the formation of HNO3 aerosols, so most pre-existing aerosols grow...

Proton transfer (PT) through and across aqueous interfaces is a fundamental process in chemistry and biology. Notwithstanding its importance, it is not generally realized that interfacial PT is quite different from conventional PT in bulk water. Here we show that, in contrast with the behavior of strong nitric acid in aqueous solution, gas-phase HNO(3) does not dissociate upon collision with th...