A selective carbazole-based fluorescent probe for chromium(III)

A novel carbazole derivative, N,N'-bis(9-ethyl-9H-carbazol-3-yl)-(ethane-1,2-diamine), has been synthesized by reacting 3-amino-9-ethylcarbazole with glyoxal and characterized by H-1 NMR, infrared spectroscopy, elemental analysis and mass spectra. The strong fluorescence emission at 438 nm of the derivative is effectively and selectively quenched by Cr3+. A 1 : 1 complex is formed between the carbazole derivative and Cr3+ and their association constant is 1.4 x 10(4) L mol(-1). The results indicate that the carbazole derivative can provide a rapid, selective and sensitive response to Cr3+ in a linear dynamic range 1.0-20 mu mol L-1 with a limit of detection of 0.10 mu mol L-1 at pH 7.4. Common interferent ions do not show any interference with the Cr3+ determination. It is anticipated that the carbazole derivative could be a good candidate probe and has potential application for Cr3+ determination.