Chemiluminometric and fluorimetric determination of folic acid

Folic acid was found to inhibit the chemiluminogenic reaction of N-bromosuccinimide with dichlorofluorescein in alkaline medium. The analyte has also been determined after generation of a fluorescing compound by the action of hexacyanoferrate(III) or N-bromosuccinimide in alkaline medium. Both procedures were further investigated and an attempt to propose the corresponding mechanisms was also made. The chemiluminogenic procedure allows the determination of folic acid within the range 6.0 to 114 mu g/ml with limits of detection and quantification equal to 2.0 and 6.0 mu g/ml, respectively and rsd at 11.4 mu g/ml equal to 1.0% (n = 12) while the fluorogenic procedure allows the determination of folic acid within the range 0.022-1.10 mu g/ml with limits of detection and quantification equal to 0.002 and 0.005 mu g/ml, respectively and rsd at 0.022 mu g/ ml equal to 0.7 (n = 10). The methods are compared and successfully applied to commercial preparations containing folic acid.