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

Abstract

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 ¹H 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 × 10⁴ 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 μmol L⁻¹ with a limit of detection of 0.10 μmol 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.