Laser induced fluorescence and photochemical derivatization for trace determination of camptothecin.

Laser-excited fluorescence was used for the selective determination of camptothecin in samples containing anti-cancer camptothecin-analogs (irinotecan and topotecan). The selectivity of the method was based on the UV photochemical derivatization in basic solution which increased the analyte fluorescence (337/450 nm) and eliminated fluorescence from the two campthotecin-analogs. The influence of UV exposure time and sodium hydroxide concentration was studied using an experimental design. Limit of detection was 4 × 10(-10) mol L(-1) with linear fluorescence response up to 1 × 10(-6)mol L(-1). Average recoveries of camptothecin (added to the samples to simulate a contamination) were 92 ± 4 and 94 ± 6% (n=3) respectively in irinotecan and topotecan based pharmaceuticals.