Spectrofluorimetric determination of trace amounts of coenzyme A using a terbium ion-ciprofloxacin complex probe in the presence of periodic acid.

A new spectrofluorimetric method was developed for the determination of trace amounts of coenzyme A (CoA). In the presence of periodic acid (H5IO6), CoA can remarkably enhance the fluorescence intensity of the Tb3+-ciprofloxacin (CIP) complex at 545 nm in a buffer solution at pH 5.4; the enhanced fluorescence intensity of the Tb3+ ion is proportional to the concentration of CoA. The optimal conditions for the determination of CoA were also investigated. The linear range and the detection limit for the determination of CoA were 6.08x10(-6)-1.64x10(-5) and 2.1x10(-8) mol L-1, respectively. This method is simple, practical and relatively free of interference from coexisting substances, and can be successfully applied to assess CoA in injection and biological samples. Moreover, the enhancement mechanism of the fluorescence intensity of the CoA-Tb3+-CIP system in the presence of H5IO6 is also discussed.