The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Aug. 25, 1981
Filed:
Mar. 26, 1980
Joseph J Kirkland, Wilmington, DE (US);
Wallace W Yau, Newark, DE (US);
E. I. Du Pont de Nemours and Company, Wilmington, DE (US);
Abstract
The method described is useful in field flow fractionation techniques for reducing separation times and improving the convenience and accuracy of measuring sizes or molecular weights of particulates. In field flow fractionation, the particulates (particles or macromolecules) are subjected to a force field and a mobile phase while passing through a flow channel. This field strength is decreased exponentially as a function of time. Alternatively the flow velocity is increased exponentially as a function of time. The initiation of the change in field strength or flow velocity may be delayed a period of time. If this time delay is made equal to the time constant of the exponential decay, the range of particulate retention time that is linearly related to the logarithm of the particle size or molecular weight is increased. An apparatus for implementing the method is also described and teaches the use of a function generator for providing the desired exponential decay and delay time. The apparatus is described in implementations involving a force field.