1) La descarga del recurso depende de la página de origen
2) Para poder descargar el recurso, es necesario ser usuario registrado en Universia

Opción 1: Descargar recurso

Detalles del recurso


It can be very informative to acquire NMR spectra of a sample as a function of the solution pH. Examples can be found in the design of host–guest complexes or in the determination of the pKa values of organic molecules. In the conventional procedure, a series of spectra must be recorded and the pH of the sample adjusted manually between successive NMR measurements. As an alternative to this laborious procedure, we demonstrate how controlled pH gradients may be established in 5 mm NMR tubes and analyzed using standard NMR equipment in a “single shot” experiment. Using 1H NMR imaging techniques and a set of NMR pH indicator compounds, we are able to measure the pH of a sample as a function of position along a pH gradient. We are thus able to obtain the necessary set of 1H NMR spectra as a function of pH from a single sample in a single NMR experiment. As proof of concept, we demonstrate how the technique may be employed for the determination of the pKa values of small organic molecules. We are able to measure pKa values from 1 to 11 to within 0.1 units of their literature values. The method is robust to variations in the setting of the pH gradients and can be readily implemented through an automated sample changer.

Pertenece a



Wallace, Matthew -  Adams, Dave J. -  Iggo, Jonathan A. - 

Id.: 71041119

Idioma: inglés  - 

Versión: 1.0

Estado: Final

Tipo:  text - 

Tipo de recurso: Articles  -  PeerReviewed  - 

Tipo de Interactividad: Expositivo

Nivel de Interactividad: muy bajo

Audiencia: Estudiante  -  Profesor  -  Autor  - 

Estructura: Atomic

Coste: no

Copyright: sí

Formatos:  text - 

Requerimientos técnicos:  Browser: Any - 

Relación: [References] http://eprints.gla.ac.uk/158263/
[References] 10.1021/acs.analchem.8b00181

Fecha de contribución: 10-mar-2018


* Wallace, M., Adams, D. J. and Iggo, J. A. (2018) Titrations without the additions: The efficient determination of pKa values using NMR imaging techniques. Analytical Chemistry , (doi:10.1021/acs.analchem.8b00181 ) (PMID:29481064) (Early Online Publication)

Otros recursos del mismo autor(es)

  1. Oscillatory nanoindentation of highly compliant hydrogels: a critical comparative analysis with rheometry We present a method for measuring the shear complex modulus of hydrogels by oscillatory nanoindentat...
  2. Does drying affect gel networks? The properties of low molecular weight gels are determined by the underlying, self-assembled network...
  3. Using aggregation-induced emission to understand dipeptide gels We describe the formation of structured liquids and gels from a functionalised dipeptide based on te...
  4. Scrolling for gels No abstract available.
  5. Nonlinear Effects in Multicomponent Supramolecular Hydrogels International audience

Otros recursos de la mismacolección

  1. An implicit hybrid method for the computation of rotorcraft flows No abstract available.
  2. An extraordinary invitation: the Education (Scotland) Act of 1918 No abstract available.
  3. Deglaciation of coastal southwestern Spitsbergen dated with in situ cosmogenic 10Be and 14C measurements The Svalbard-Barents ice sheet was predominantly a marine-based ice sheet and reconstructing the tim...
  4. A trillion frames per second: The techniques and applications of light-in-flight photography Cameras capable of capturing videos at a trillion frames per second allow to freeze light in motion,...
  5. Superconducting coincidence photon detector with short timing jitter No abstract available.

Aviso de cookies: Usamos cookies propias y de terceros para mejorar nuestros servicios, para análisis estadístico y para mostrarle publicidad. Si continua navegando consideramos que acepta su uso en los términos establecidos en la Política de cookies.