Flow-injection chemiluminescence determination of enalapril maleate in pharmaceuticals and biological fluids using tris(2,2′-bipyridyl)ruthenium(II)

A chemiluminescence (CL) method using flow injection (171) has been investigated for the rapid and sensitive determination of enalapril maleate. The method is based on the CL reaction of the drug with tris(2,2'-bipyridyl)ruthenium(II), Ru(bipy)(3)(2+) and acidic potassium permanganate. After selecting the best operating parameters, calibration graphs were obtained over concentration ranges of 0.005 - 0.2 mug/ml and 0.7 - 100 mug/ml with a detection limit (S/N = 2) of 1.0 ng/ml. The average % found was 99.9 +/- 0.7 and 100.2 +/- 0.3 for the two concentration ranges respectively. %RSD (n = 10) for 5.0 mug/ml was 0.44. The method was successfully applied to the determination of enalapril maleate in dosage forms and biological fluids without interferences.