A single spectroscopic flow-through sensing device for determination of ciprofloxacin

A simple flow injection UV spectrophotometric sensing device was developed for the determination of ciprofloxacin. The method is based on its transient retention and concentration on Sephadex SP C-25 cation-exchange gel beads packed in the flow cell and the continuous monitoring of its native absorbance on the solid phase at 277 nm. The procedure is carried out without any derivatisation. Formic acid/NaOH 1.75 M at pH 2.2 is used as carrier solution in a simple monochannel FIA manifold. When the analytical signal reached the maximum value, ciprofloxacin was eluted from the solid support by the carrier solution itself. The response of the sensor was linear in the concentration range 0.5-10 microg ml(-1) with an RSD (%) of 0.79, a detection limit (3sigma criterion) of 0.035microg ml(-1) and a sampling rate of 16 h(-1). Application to the analysis of pharmaceutical samples testifies the utility of this sensor.