Abstract: An improved technique and apparatus for the independent measurement of anions and cations in solution, wherein the sample ions are chromatographically displaced in a plurality of ion exchange columns by an eluting ion which is or is made light-absorbing and wherein the sample ions are detectable from decrements in absorbance of the eluting ions as revealed by photometric monitoring; and the sample ions, cations and anions, are further detected independently by means for monitoring eluting anion and cation absorbance differences calibrated according to characteristic absorbance ratios of the selected eluting ion species at a plurality of wavelengths.
Type:
Grant
Filed:
January 24, 1986
Date of Patent:
July 14, 1987
Assignee:
The Dow Chemical Company
Inventors:
Theodore E. Miller, Jr., Ziad Iskandarani
Abstract: The molecular weight and molecular weight distribution of diverse ultra-high molecular weight water soluble polymers is rapidly determined based on apparent size by passage of extremely dilute samples of the polymer (1-250 ppm) through a column of nonporous packing whereby separation into molecular weight (apparent size) fractions is obtained predominantly based on flow (i.e., hydrodynamic chromatography). Detection of the extremely dilute sample polymer is accomplished, e.g., by tagging the polymer with a fluorescent agent and using a flow-through fluorometer detector. The molecular weight characterization of the polymers is determined independent or less dependent of the composition of the polymer by analyzing the sample in its nonionized form.
Type:
Grant
Filed:
May 24, 1985
Date of Patent:
December 16, 1986
Assignee:
The Dow Chemical Company
Inventors:
Robert K. Prud'homme, Frederick W. Stanley, Jr., Martin W. Langhorst
Abstract: A method for treating imaged lithographic printing plates with a solution comprising (1) water, (2) an active polymer component for rendering non-image areas of a lithographic printing plate hydrophilic, comprised of a polyacrylamide-based polymer or copolymer or a blend of polyacrylamide and polyacrylic acid, or the like, said polymer or copolymer or blend having an average molecular weight of from about 5,000 to about 10.sup.