Application of f--f luminescence of terbium ion for determination of non-steroidal anti-inflammatory drug-niflumic acid.

A simple, rapid and sensitive luminescence method for determination of niflumic acid (NFA) is described. The method is based on the intramolecular energy transfer from niflumic acid to terbium ion (Tb(3+)) in the presence of trioctylphosphine oxide (TOPO). Optimum conditions for the formation of the NFA-Tb(3+)-TOPO ternary complex have been investigated. The calibration graph is linear over the range 0.002--0.02 microg ml(-1). The relative standard deviation is close to 4%. The recoveries obtained by applying the method to the analysis of urine ranged from 94--102%.