Design and synthesis of dual-excitation fluorescent probe, Tb3+-dtpa-bis(fluorescein), and application in detection of hydrazine in environmental water samples and live cells

Abstract

A novel dual-excitation fluorescent probe, Tb3+-dtpa-bis(fluorescein), for detecting hydrazine is designed based on the special emissions of Tb3+-dtpa-BHz and fluorescein at 515 nm and 520 nm, respectively, under 247 nm and 480 nm excitation wavelength lights. The affecting factors including hydrazine concentration, solution pH value and interfering substances on the detection of hydrazine are examined. The high sensitivity and high specificity of Tb3+-dtpa-bis(fluorescein) in hydrazine detection could be confirmed. Two good linear responses of fluorescence emission intensities of Tb3+-dtpa-bis(fluorescein) at 515 nm and 520 nm as functions of hydrazine concentration in range of 3.00 × 10−5 mol L−1 - 4.50 × 10−5 mol L−1 are obtained, respectively. The LOD of 13 ppb (4.08 × 10−7 mol L−1) for 247 nm wavelength light excitation and 8 ppb (2.50 × 10−7 mol L−1) for 480 nm wavelength light excitation are achieved, which are close to and lower than TLV (10 ppb) of the EPA, respectively. The theoretical calculations on HOMO-LUMO energy levels and the interfacial plots of the molecular orbitals for probe and its final product based on density functional theory (DFT) are performed. In addition, the detections of hydrazine in real water samples and living cells are also studied. The experimental results indicated that the developed fluorescent probe could be applied for the determination of hydrazine in environmental water samples and living cells.