Determination of Carboxylesters by Indirect Photometric Ion Chromatography with an On-Line Enzyme Immobilized Column

Abstract

Carboxylesters, carboxylic and inorganic anions were determined separately by photometric ion chromatography with an enzyme immobilized column. In the system, a carboxylesterase immobilized column (4.6 mm i.d.× 10 mm), which converted carboxylesters to carboxylic anions completely, was set between a sample injector and an analytical column. The other chromatographic conditions were as follows: an anion exchanger-type separation column (4.6 mm i.d.×250mm); phthalate-N-2-hydroxyethylpiperazine-N’-2-ethanesulfonic acid eluent (pH 6.5); an oven of temperature 40°C; a flow rate of 1.0ml/min; 280-nm UV detection; and an injection volume of 20 μl. Calibration curves for ethyl esters of acetate, propionate, butyrate and isovalerate were linear with the range 5×10-10mol to 1 × 100-7 mol according to the peak-height method; their detection limits were 10-10 mol levels. The present method was applied for the determination of carboxylesters in practical samples