Method and apparatus for characterizing solutions of small particles

US7294513B2 · kind B2 · utility

Assignee

• Wyatt Technology, LLC · US

Inventor

• Philip J. Wyatt · Redlands, US

Key dates

• Filing date: Feb 16, 2007
• Grant date: Nov 13, 2007
• Expiry date: Feb 16, 2027

Classification

• Technology area (CPC Y): Emerging Cross-Sectional Technologies
• CPC primary: Y10T436/25375
• WIPO field: Measurement
• WIPO sector: Instruments

Abstract

A method and apparatus is described by which means molecules in suspension may be characterized in terms of the size and mass distributions present. As a sample solution is separated by centrifugal means, it is illuminated at a particular radial distance from the axis of rotation by a fine, preferably monochromatic, light beam. Despite the high resolution of such devices, a key problem associated with most separators based upon use of centrifugal forces is the difficulty in deriving the absolute size and/or molar mass of the separating molecules. By integrating means to detect light scattered, over a range of scattering angles, from samples undergoing centrifugal separation, molecular sizes in the sub-micrometer range may be derived, even in the presence of diffusion. Adding a second light beam at a displaced rotational angle, preferably of an ultraviolet wavelength, that intersects the sample at the same radial region as the first beam permits determination of the molecular concentration at that region. Combining the light scattering data with the associated concentration permits the determination of the associated molar mass. In a preferred embodiment, the light beam and detector…