Determination of three fluoroquirkolone drugs by flow injection chemiluminescence

A new flow injection chemiluminescence ( CL) method has been developed for the determination of three fluoroquinolone drugs, namely norfloxacin, ofloxacin and ciprofloxacin. When the soluble MW was injected into a combined stream of the fluoroquinolone with formaldehyde, a strong CL signal was observed. Under the selected experimental conditions (2 x 10(-4) mol/L soluble Mn(IV)-3% formaldehyde-3 mol/L phosphoric acid medium), the linear ranges were 1.0 x 0(-7) - 1. 0 x 10(-5) mol/L for norfloxacin, 1. 0 x 10(-7) - 1. 0 x 10(-5) mol/L for ofloxacin and 3. 0 x 10(-7) - 5. 0 x 10(-5) mol/L ciprofloxacin, the detection limits (3 sigma) were 3 x 10(-8) mol/L norfloxacin, 3 x 10(-8) mol/L ofloxacin and 1 x 10(-7) mol/L ciprofloxacin, the relative standard deviations ( 5 x 10(-6) mol/L fluoroquinolone antibiotics, n = 11) were 2. 6% 1. 6% and 2. 8% respectively. The method was applied to the determination of norfloxacin in capsules. A possible CL reaction mechanism was also discussed.