FAST DETERMINATION OF NAPROXEN IN SERUM BY STOPPED-FLOW ROOM-TEMPERATURE LIQUID PHOSPHORIMETRY

The stopped-flow mixing technique was used to develop an automated roo m-temperature liquid phosphorimetric method for the straightforward, f ast determination of naproxen in serum samples. The interaction of nap roxen with thallium(I) ions in the presence of sodium dodecyl sulfate allows one to obtain a kinetic curve that levels off within only 2 s. This approach allows the development of very fast kinetic and equilibr ium methods by using the slope and amplitude of the kinetic curve, whi ch are directly proportional to the naproxen concentration, as analyti cal parameters. The linear calibration range thus achieved is 0.06-15 or 0.08-15 mu g mL(-1), depending on wheather slope or amplitude measu rements are used. The within- and between-assay precision data, as wel l as the selectivity of the method are more than adequate for the dete rmination of naproxen in serum samples pretreated with acetonitrile. A nalytical recoveries range from 90.7 to 104.0%.