A hollow fiber based microextraction suitable for the determination of the herbicide glyphosate and its main metabolite amionomethylphosphoric aicd was developed. A solution of 0.20 M aliquat 336, a cationic carrier, in di-n-hexyl ether was used as the membrane support liquid. The membrane lumen was filled with 20.0 µL of 1.0 M potassium chloride before dipping in a 20.0-mL of sample solution adjusted to pH 9.0. After a 60-minute extraction, the acceptor phase was analyzed by high-performance liquid chromatography with post-column derivatization. The enrichment factors obtained for glyphosate and aminomethylphosphonic acid were 814 and 141, respectively. The method detection limits were 0.3 µg/L for glyphosate and 1.5 µg/L for aminomethylphosphonic acid. Percent relative standard deviations (n=10) of glyphosate and aminomethylphosphonic acid at 5 µg/L spiked level, were 11.86 and 7.33%, respectively. In general, the developed carrier-mediated supported-liquid membrane technique demonstrated high enrichment capability with good reproducibility. The technique consumed very little organic solvent, inexpensive, simple, and environmental friendly. The method was tested with ground water samples and proved to be feasible for the determination of both analytes in ground water.
