Search results for "Ammonium Chloride"
showing 10 items of 48 documents
Protonation thermodynamics of 2,2'-bipyridyl in aqueous solution. Salt effects and weak complex formation
1993
Abstract Protonation constants of 2,2'-bipyridyl (bipy) have been determined potentiometrically, using (H + )-glass electrode, in different aqueous media (alkali and alkaline earth chlorides, tetramethylammonium chloride and tetramethylammonium iodide) at different temperatures and ionic strengths. The differences in log K H values are explained using a complex formation model. Formation thermodynamic parameters are given.
Protonation of Carbonate in Aqueous Tetraalkylammonium Salts at 25°C.
2006
Protonation constants of carbonate were determined in tetramethylammonium chloride (Me4NClaq 0.1≤I/mol kg−1 ≤4) and tetraethylammonium iodide (Et4NIaq 0.1≤I/mol kg−1 ≤1) by potentiometric ([H+]-glass electrode) measurements. Dependence of protonation constants on ionic strength was taken into account by modified specific ion interaction theory (SIT) and by Pitzer models. Literature data on the protonation of carbonate in NaClaq (0.1≤I/mol kg−1 ≤6) were also critically analysed. Both protonation constants of carbonate follow the trend Et4NI>Me4NCl > NaCl. An ion pair formation model designed to take into account the different protonation behaviours of carbonate in different supporting electr…
Ion-pair in-tube solid-phase microextraction and capillary liquid chromatography using a titania-based column: application to the specific lauralkoni…
2012
Abstract A quick, miniaturized and on-line method has been developed for the determination in water of the predominant homologue of benzalkonium chloride, dodecyl dimethyl benzyl ammonium chloride or lauralkonium chloride (C 12 -BAK). The method is based on the formation of an ion-pair in both in-tube solid-phase microextraction (IT-SPME) and capillary liquid chromatography. The IT-SPME optimization required the study of the length and nature of the stationary phase of capillary and the processed sample volume. Because to the surfactant character of the analyte both, the extracting and replacing solvents, have played a decisive role in the IT-SPME optimized procedure. Conditioning the capil…
Peroxodisulfate as a chemical initiator for methacrylate-ester monolithic columns for capillary electrochromatography
2008
Organic monolithic stationary phases for CEC were synthesized in situ in fused-silica capillaries. Polymerization mixtures were composed of butyl methacrylate, ethylene dimethacrylate, and [2-(methacryloyloxy)ethyl]trimethyl ammonium chloride in the presence of a porogenic solvent, using ammonium peroxodisulfate as chemical initiator, and N,N,N',N'-tetramethylethylenediamine to activate the reaction. The influence of the amount of initiator, temperature, and composition of porogenic solvent on the physical and chromatographic properties of monolithic stationary phases has been investigated. A minimum plate height of 14.5 microm was obtained at 18 wt% of 1,4-butanediol in the polymerization …
CCDC 261837: Experimental Crystal Structure Determination
2006
Related Article: S.Busi, M.Lahtinen, M.Karna, J.Valkonen, E.Kolehmainen, K.Rissanen|2006|J.Mol.Struct.|787|18|doi:10.1016/j.molstruc.2005.10.027
Novel cationic polyaspartamide with covalently linked carboxypropyl-trimethyl ammonium chloride as a candidate vector for gene delivery
2006
Abstract The non-viral gene vector properties of a protein-like polymer, the α,β-poly(N-2-hydroxyethyl)- d , l -aspartamide (PHEA) were investigated after its derivatization with 3-(carboxypropyl)trimethyl-ammonium chloride (CPTA) as molecule bearing cationic groups, in order to obtain stable polycations able to condense DNA. PHEA was firstly functionalized with hydrazide pendant groups by reaction with hydrazine monohydrate (HYD), obtaining the polyhydrazide α,β-poly(N-2-hydroxyethyl/carbazate)- d , l -aspartamide (PHEA–HYD). In this paper we reported that polymer functionalization degree can be easily modulated by varying reaction conditions, so allowing us to produce two PHEA derivatives…
Mechanisms underlying the nitric oxide inhibitory effects in mouse ileal longitudinal muscle
2005
We investigated the mechanisms involved in the nitric oxide (NO)-induced inhibitory effects on longitudinal smooth muscle of mouse ileum, using organ bath technique. Exogenously applied NO, delivered as sodium nitroprusside (SNP; 0.1–100 µmol/L) induced a concentration-dependent reduction of the ileal spontaneous contractions. 1H-[1,2,4]oxadiazolol[4,3,a]quinoxalin-1-one (ODQ; 1 µmol/L), a guanilyl cyclase inhibitor, reduced the SNP-induced effects. Tetraethylammonium chloride (20 mmol/L), a non-selective K+ channel blocker, and charybdotoxin (0.1 µmol/L), blocker of large conductance Ca2+-dependent K+ channels, significantly reduced SNP-induced inhibitory effects. In contrast, apamin (0.1…
Different mechanisms of the inhibition of the transient outward current in rat ventricular myocytes.
1994
The mechanism of drug-induced inhibition of the transient outward current, Ito, has been investigated in rat ventricular myocytes using the whole cell patch clamp technique. Ito was activated by 300 ms depolarizing voltage clamp steps in 10 mV increments from −50 mV up to +40 mV. At +40 mV, Ito peaked after about 3 ms, and the time course of inactivation was appropriately described by two time constants, τfast = 17 ms and τslow = 203 ms. Verapamil, quinidine sulfate and nifedipine preferentially depressed Ito at the end of the 300 ms depolarizing voltage clamp step; the inactivation of Ito was accelerated by all drugs, whereas peak Ito was less affected. The time course of drug action at +4…
Characterization of the muscarine receptors involved in the modulation of serotonin release from the vascularly perfused small intestine of guinea pi…
1989
Isolated small intestinal segments of the guinea pig were arterially perfused and the release of 5-hydroxytryptamine (5-HT) and its metabolite 5-hydroxyindoleacetic acid (5-HIAA) into the portal venous effluent measured by HPLC with electrochemical detection. Test substances were applied via the arterial perfusion medium. McN-A-343, pilocarpine and oxotremorine inhibited concentration-dependently the outflow of 5-HT and 5-HIAA. Pirenzepine (0.03-0.1 mumol/l) which can discriminate between M1 and M2-receptor subtypes antagonized completely this inhibitory effect. In the presence of 1 mumol/l tetrodotoxin (TTx), all three muscarine receptor agonists increased the outflow of 5-HT and 5-HIAA. O…
Resistance of Immobilized Lactic Acid Bacteria to the Inhibitory Effect of Quaternary Ammonium Sanitizers
2001
Abstract The inhibitory effect of quaternary ammonium sanitizers (QAS) on the fermentation activity of lactic acid bacteria was investigated. Benzalkonium chloride and didecyl dimethyl ammonium chloride show the same inhibitory effect. In MRS agar medium and MRS liquid medium their minimum inhibitory concentration was below 2 μg/mL. Interfering molecules in milk increased this concentration of inhibitory QAS above 8 μg/mL. Both growth and acidification were decreased but by immobilizing cells in calcium alginate gel beads this inhibitory effect could be reduced. The longer the beads were used for successive acidification and were colonized by lactic acid bacteria, the better was the acidifi…