Determination of ciprofloxacin with a room-temperature phosphorescence flow-through sensor based on lanthanide-sensitized luminescence

Direct measurement of the sensitized luminescence of the europium-ciprofloxacin chelate immobilized on a cationic exchanger was used to develop a flow-through room-temperature phosphorescence optosensor for determination of ciprofloxacin. The phosphorescent chelate is formed on-line at room temperature in a flow-injection system and is immobilized on a weakly acidic cation-exchange resin packed in a flow cell. Optimum experimental conditions and analytical performance are discussed in detail. The sensor response for ciprofloxacin was linear, from 1.5 x 10(-6) to 2.0 x 10(-5)M with a relative standard deviation of 2.5% (n = 10) and a detection limit of 1.1 x 10(-7)M. The effect of possible interferences on sensor response was studied. The sensor was successfully tested for the determination of ciprofloxacin in pharmaceutical formulations.