Determination of three fluoroquinolone 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 MnflV) was injected into a combined stream of the fluoroquinolone with formaldehyde, a strong CL signal was observed. Under the selected experimental conditions (2 × 10^-4 mol/L soluble Mn(I\0-3% formaldehyde-3 mol/L phosphoric acid medium), the linear ranges were 1.0 × O^-7-1.0 ×l0^-5 mol/L for norfloxacin, 1.0 ×l0^-7-1. 0 × 10^-5 mol/L for ofloxacin and 3.0×10^-7.0×10^-5 mol/L ciprofloxacin, the detection limits (3σ) were 3 × 10^-8 mol/L norfloxacin, 3 × 10^-8 mol/L ofloxacin and 1 × 10^-7 mol/L ciprofloxacin, the relative standard deviations (5 × 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.