Preconcentration technique for nonylphenol using cellulose cotton with homogenous liquid-liquid extraction for liquid chromatographic analysis.

A powerful preconcentration method for nonylphenol (NP) has been developed for liquid-chromatography by combining the use of cellulose cotton (solid-phase extraction) with homogeneous liquid-liquid extraction. A 100 ml of sample solution was preconcentrated using cotton, and the eluate obtained (acetonitrile; 5 ml) was further preconcentrated to 50 microl within 10 min using a homogeneous liquid-liquid extraction method (volume ratio, 2,000-fold; 100 ml--> 50 microl). The sample concentration increases from preconcentration was 1,599-fold, and NP was extracted into the sedimented phase at 80%. The proposed method was applied to high performance liquid chromatography with fluorescence detection (FL/HPLC); the lowest determination limit obtained was 1.0 x 10(-9) mol l(-1).