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Nitrophenyl Octyl Ether (nitrophenyl + octyl_ether)

Distribution by Scientific Domains

Chemistry	100%

Selected Abstracts

Solvatochromic Analysis of Partition Coefficients in the o -Nitrophenyl Octyl Ether (o -NPOE)/Water System

HELVETICA CHIMICA ACTA, Issue 11 2003
Xiangli Liu
The objective of this study was to unravel the structural properties responsible for the partitioning of solutes in o -nitrophenyl octyl ether (o -NPOE)/H2O, a new solvent system for the determination of the partition coefficients of ions. A set of 88 compounds (including drugs) was selected to allow a regular and broad distribution of property spaces. Partition coefficients in o -NPOE/H2O (log,Pnpoe) were measured by the shake-flask or the potentiometric method. Linear solvation free-energy relationship (LSER) analyses showed that Van der Waals volume, H-bond-acceptor basicity, and H-bond-donor acidity are the three molecular descriptors of solutes determining their log,Pnpoe values. The partitioning mechanism of the investigated compounds in o -NPOE/H2O is controlled by the same structural properties as it is in 1,2-dichloroethane (DCE)/H2O. ,log,Poct,npoe Values (difference between log,Poct and log,Pnpoe) express mainly dipolarity/polarizability and H-bond-donor acidity. The solvent o -NPOE is shown to be a good candidate to replace DCE in measurements of lipophilicity. [source]

Amperometric Sensor for Heparin: Sensing Mechanism and Application in Human Blood Plasma Analysis

ELECTROANALYSIS, Issue 13-14 2006
Jan Langmaier
Abstract Voltammetric measurements of heparin at a rotating glassy carbon (GC) electrode coated with a polyvinylchloride membrane are reported. A spin-coating technique is used to prepare thin membranes (20,40,,m) with a composition of 25% (w/w) PVC, 1,1,-dimethylferrocene as a reference electron donor for the GC|membrane interface, nitrophenyl octyl ether (o -NPOE) or bis(2-ethylhexyl) sebacate (DOS) as a plasticizer, and hexadecyltrimethylammonium tetrakis(4-chlorophenyl) borate (HTMATPBCl) or tridodecylmethylammonium tetrakis(4-chlorophenyl) borate (TDMATPBCl) as a background electrolyte. It is shown that the electrodes coated with either the HTMA+/o -NPOE (DOS) or TDMA+/o -NPOE (DOS) membrane provide a comparable amperometric response towards heparin (1,10,U mL,1) in the aqueous solution of 0.1,M LiCl. However, only the membranes formulated with TDMATPBCl can be used for an amperometric assay of heparin in human blood plasma with a detection limit of 0.2,U mL,1. Effects of membrane composition, heparin concentration, rotation speed and sweep rate on the voltammetric behavior of heparin provide some insight into the sensing mechanism. Theoretical analysis of the amperometric response is outlined, and the numeric simulation of the voltammetric behavior is presented. [source]

Amperometry of Heparin Polyion Using a Rotating Disk Electrode Coated with a Plasticized PVC Membrane

ELECTROANALYSIS, Issue 2 2006
Jan Langmaier
Abstract Electrochemical method of detection of heparin polyion was developed based on voltammetry of heparin on a rotating glassy carbon (GC) electrode coated with a plasticized PVC membrane. The membrane was deposited on the GC disk by spin-coating technique using a mixture of solutions of PVC in tetrahydrofuran, and 1,1,-dimethylferrocene (DMFc) and hexadecyltrimethylammonium tetrakis(4-chlorophenyl)borate (HTMATPBCl) in o -nitrophenyl octyl ether. UV/vis reflection spectrometry was used to evaluate the membrane thickness, which exhibits a linear correlation with the membrane resistance measured by impedance spectroscopy. It is shown that this electrode can be used for amperometric or coulometric detection of heparin in aqueous samples of medically relevant concentrations (1,10,U mL,1), with a detection limit of 1.4,U mL,1. Evidence is provided indicating that the current determining step is the reversible adsorption of the ion-pair of heparin polyion with HTMA+ cation at the membrane/aqueous electrolyte interface, which is driven by oxidation of DMFc at the GC/membrane interface. [source]