SIMULTANEOUS FLOW-INJECTION DETERMINATION OF ACETYLCHOLINE AND CHOLINE BASED ON LUMINOL CHEMILUMINESCENCE IN A MICELLAR SYSTEM WITH ONLINE DIALYSIS

A simultaneous flow injection method (FIA) was developed for the deter mination of acetylcholine and choline. This method is based on the det ermination of hydrogen peroxide (H2O2) produced from acetylcholine and choline by enzyme reactions. The determination of H2O2 was carried ou t by Co(II)-catalyzed luminol chemiluminescence (CL) reaction. The add ition of sodium dodecylsulfate (SDS) in this CL system enhanced the CL intensity and sodium hydrogencarbonate showed an activating effect on the catalysis of Co(II) on the CL reaction. Interference of albumin f or the CL reaction was removed by introducing an on-line dialysis unit and anion exchange column in the FIA system. A 10(-6) mol dm(-3) leve l of acetylcholine and choline can be determined at a rate of 6 sample s per hour (12 peaks). The method was successfully applied to the dete rmination of acetylcholine and choline in a culture medium.