Carbazole as fluorescence carrier for preparation of doxycycline sensor.

Carbazole is a promising pharmaceutical species. A novel optical sensor for determining doxycycline based on the fluorescence quenching of N-allylcarbazole immobilized on an quartz glass plate surface by covalent bonding has been described. The sensor shows satisfactory virtues in reversibility, repeatability, selectivity and sufficient lifetime resulting from its excellent optode membrane. Its response time is less than 60 s. The determination range and detection limit of the sensor are 6.0 x 10(-7)-2.0 x 10(-3) M and 2.0 x 10(-7) M, respectively. The lifetime of each sensor is at least three to four months. The sensor can be used for direct determination of doxycycline in pharmaceutical preparations and urine samples.