Nuclear magnetic resonance (NMR) spectroscopy has been used to obtain metabolic profiles of the polar diatom Fragilariopsis cylindrus, leading to the identification of a novel metabolite in this organism. Initial results from an ongoing metabolomics study have led to the discovery of isethionic acid (2-hydroxyethanesulfonic acid, CAS: 107-36-8) as a major metabolite in F. cylindrus. This compound is being produced by the organism under normal culture conditions. This finding is the first report of a diatom producing isethionic acid. In addition to isethionic acid, four other metabolites, dimethylsulfoniopropionate (DMSP), betaine, homarine, and proline were present and may serve as osmoprotectants in F. cylindrus. NMR-based metabolite profiles of F. cylindrus were obtained along a growth curve of the organism. The relative concentration levels of the five metabolites were monitored over a growth period of F. cylindrus from 18 to 25 days. All showed an increase in relative concentration with time, except for proline, which began to decrease after day 21.
Admicelle based extractions, where sorbents used are prepared by immobilizing charged surfactants in a bilayer arrangement onto a silica or aluminum oxide surface, have been used for preconcentrating a wide variety of analytes. These analytes have a certain degree of hydrophobicity interacting with the alkyl chains of the surfactant or they are counter-charged interacting electrostatically with the charged polar group of the surfactant. Weakly hydrophobic molecules are more challenging to efficiently extract onto this type of medium. Presented is an admicelle extraction procedure for extracting weak acid phenols. An acid-base reaction takes place between modified surfactants containing hydroxide counter ions and weak acid phenols. The result of this reaction is the production of phenolate ions that remain counter to the cationic surfactant. The acid-base reaction together with the fluid nature of the surfactant phase protects the phenolate ions from being removed by counter ions in natural solutions. High extraction efficiencies result.
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