Determination of bromoxynil and ioxynil in the presence of carbamates by supported liquid membrane-liquid chromatography in river waters

Abstract

Sample pre-treatment and enrichment using the supported liquid membrane (SLM) technique for the determination of phenolic nitrile herbicides in presence of carbamates in river water samples was investigated. The uncharged herbicide molecules from the flowing aqueous solution diffuse through an immobilized water-immiscible organic solvent, supported by a porous polytetrafluoroethylene (PTFE) membrane, and trapped in a stagnant acidic acceptor phase in an ionic form. Using n-undecane as a membrane solvent, the SLM extraction methodology was successfully used for the enrichment and separation of phenolic nitrile herbicides in environmental waters with extraction efficiencies of 60% or better. A RDS (%) of 2.1 and 1.8 was obtained for the extraction of ioxynil and bromoxynil from river water, respectively.

KEY WORDS: Bromoxynil, Ioxynil, Phenolic nitrile herbicides, Carbamates, Supported liquid membrane, Sample pre-treatment, Sample enrichment

Bull. Chem. Soc. Ethiop. 2003, 17(2), 119-128.