Method for the determination of very small magnetic susceptibilities and probehead for a high resolution nmr spectrometer for the purpose of carrying out the method

US5221903A · kind A · utility

Assignee

• Bruker Analytische Messtechnik GmbH · DE

Inventors

• Arne Kasten · Karlsruhe, DE
• Reinhard Biehl · Karlsruhe, DE

Key dates

• Filing date: Oct 3, 1991
• Grant date: Jun 22, 1993
• Expiry date: Oct 3, 2011

Classification

• Technology area (CPC G): Physics
• CPC primary: G01R33/46
• WIPO field: Measurement
• WIPO sector: Instruments

Abstract

An NMR spectrometer is utilized in order to determine the magnetic susceptibility of a sample, in which, by means of the sample, a change in the homogeneous magnetic field in the region of a probe substance is effected and the change in the spectrum of the probe substance which is thereby caused is observed. A method known in the art is based on the modulation of the resonance frequency which occurs when the probe substance is caused to rotate about an axis perpendicular to the direction of the magnetic field. The application of this method encounters difficulties with spectrometers whose probe volume is penetrated axially by the magnetic field. In accordance with the invention, by means of the sample (14), a change is produced in the magnetic field along the probe axis in a sample substance (12) preferentially positioned along the direction of the magnetic field. This change effects a structuring of the resonance line with maxima whose distance is directly proportional to the susceptibility of the sample substance. A proportionality factor is dependent (upon the geometry of the sample (14). Preferentially a fluid in a double walled tube (11, 13) is utilized as probe substance (12)…