Novel approaches to ionic chromatography: Progress report

Technical Report · Fri Jan 01 04:00:00 EST 1988

OSTI ID:6843307

Dasgupta, P K

In the area of membrane-suppressed anion chromatography, new membranes, some produced in our laboratory, others custom made for us by Perma-Pure Products, all in tubular form, have been utilized to design and build devices of unprecedented transport characteristics. We are now able to quantitatively exchange 500 ..mu..eq NaOH/min (0.5 M NaOH flowing at 1 mL/min) without any observable band dispersion with the best available commercial columns. Because of these considerably superior membrane characteristics, we have returned to the simple, low-pressure drop, single membrane, filament-filled helix designs. We are able to prepare asymmetric membranes by coating a porous inert tubular membrane (e.g., made of polypropylene, Celgard /times/ 2400) in diameters of 100-400 ..mu..m with 5-25 ..mu..m coating of an ion exchanger, e.g., Nafion or a nonporous permselective material, e.g., silicone rubber. The coating is applied from solution and can be recoated repeatedly to achieve essentially any desired thickness. These tubes have the structural strength of the base material (burst strength greater than or equal to400 psi) and transport characteristics of the thin deposited layer and as such, are bound to see use in a variety of areas. When using very thin active-layer membrane based suppressor in IC, regenerant penetration becomes a significant problem. This has been solved by using carefully purified poly(styrene sulfonic acid) as regenerant which is continuously recirculated through a large bed exchanger. The latter is periodically replaced or regenerated off-line. The silicone-coated membranes have allowed us to essentially completely remove CO/sub 2/ from carbonate-based eluents, operating under significant pressure at room-temperature.

• Research Organization: Texas Tech Univ., Lubbock (USA). Dept. of Chemistry and Biochemistry
• DOE Contract Number: FG05-84ER13281
• OSTI ID: 6843307
• Report Number(s): DOE/ER/13281-2; ON: DE88017068
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
400105* -- Separation Procedures
ANIONS
AQUEOUS SOLUTIONS
ASYMMETRY
CHARGED PARTICLES
CHROMATOGRAPHY
COMPOSITE MATERIALS
DISPERSIONS
DOCUMENT TYPES
ELECTRIC CONDUCTIVITY
ELECTRICAL PROPERTIES
FABRICATION
FREQUENCY DEPENDENCE
ION EXCHANGE CHROMATOGRAPHY
ION EXCHANGE MATERIALS
IONS
MATERIALS
MEMBRANES
MIXTURES
PERFORMANCE
PHYSICAL PROPERTIES
PROGRESS REPORT
SEPARATION PROCESSES
SOLUTIONS