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Biomedical subjects

H F Walton

Publications and source records attributed to H F Walton.

11 recordsLinked to original sources
PubMed1979

Chromatography of xanthines on ion-exchange resins.

Short columns of a 4% crosslinked cation-exchange resin gave good chromatography of xanthines, including caffeine, theophylline and hypoxanthine, and related polar aromatic compounds. Elution volumes and sequences can be modified by changing pH, solvent composition and resin counter-ion. A macroporous cation-exchange resin showed exaggerated counter-ion effects. A method is described for determining caffeine and theophylline in blood serum, using the 4% crosslinked resin with aqueous sodium phosphate eluent of pH 7.5; the temperature was 65 degrees. Detection limits are 10 ng and less.

Caffeine↗
PubMed1977

Environmental trace analysis of organics in water by glass capillary column chromatography and ancillary techniques. Products of ozonolysis.

A method employing a polymeric sorbent has been used for analysis of volatile organic components in water. Trace level organics are sparged from water with nitrogen gas and are concentrated on Tenax GC prior to analysis with either flame ionization gas chromatography or gas chromatography-mass spectrometry. Glass capillary columns were used to obtain maximum resolution of chromatographic peaks. Specifically, the method has been applied to a qualitative and quantitative study of the products which result from ozonization of secondary treated domestic wastewater. The principal volatile products of ozonolysis are n-hexanal, n-heptanal, n-octanal and n-nonanal. Representative samples contained 0.7 ppb** of n-heptanal and less than 1 ppb of any of the volatile compounds.

Chromatography, Gas↗
PubMed1975

Ligand-exchange chromatography of alkaloids.

Alkaloids are separated by liquid chromatography on resins having functional carboxyl groups combined with copper (II) ions. The eluent is aqueous alcohol containing ammonia. Some resins retain alkaloids much better than others. Alkaloids studied included morphine, codeine, strychnine, atropine, papaverine, narcotine, cocaine, quinine, cinchonine and methadone.

Alkaloids↗