Flow injection chemiluminescence determination of loxoprofen and naproxen with the acidic permanganate-sulfite system

A novel flow injection chemiluminescence(CL)method for the determination of loxoprofen and naproxen was proposed based on the CL system of KMnO4 and Na2SO3 in acid media.The CL intensity of KMnO4-Na2SO3 was greatly enhanced in the presence of loxoprofen and naproxen.The mechanism of the CL reaction was studied by the kinetic process and UV-vis absorption and the conditions were optimized.Under optimized conditions,the CL intensity was linear with loxoprofen and naproxen concentration in the range of 7.0×10-8-1.0×10-5g/mL and 2.0×10-7-4.0×10-6g/mL with the detection limit of 2.0×10-8g/mL and 3.0×10-8g/mL(S/N=3),respectively.The relative standard deviations were 2.39% and 1.37% for 5.0×10-7g/mL naproxen and 5.0×10-7g/mL loxoprofen(n=10),respectively.The proposed method was satisfactorily applied to the determination of loxoprofen and naproxen in pharmaceutical preparations.