Lighting of a rhodamine-based fluorescent lamp using ClO4− as a connector: detection by the naked eye and cell imaging studies of trace amounts of ClO4− ions

Abstract

A visible light excitable (λ_ex = 520 nm), rhodamine-based, perchlorate selective ‘turn on’ fluorescent probe, RHENTU, is prepared and characterized by spectroscopic techniques. The probe is suitable for use in the detection of ClO₄⁻ by the naked eye. It is also capable of detecting ClO₄⁻ in contaminated living cells under a fluorescence microscope. Common anions viz. F⁻, Cl⁻, Br⁻, I⁻, N₃⁻, NCO⁻, NO₂⁻, NO₃⁻, SCN⁻, CN⁻, CH₃COO⁻, SO₄²⁻ and H₂PO₄⁻ do not interfere with these processes. The binding constant of RHENTU for ClO₄⁻ has been determined to be 2.9 × 10³ M^−1/2 using the Benesi–Hildebrand equation. Addition of ClO₄⁻ to RHENTU afforded an intense red emission with a quantum yield (4.5 × 10⁻²) five times greater than that of free RHENTU. The lowest detection limit (LOD) of RHENTU for ClO₄⁻ is 1 × 10⁻⁷ M.