Sensitive detection of sulfide ions in red region based on luminescence resonance energy transfer between upconversion nanoparticles and dye‐670

Many sulfides are toxic substances that easily harm the respiratory tract, therefore affecting respiratory function or damaging other organs of the body, leading to its failure. Therefore, there is a pressing need to develop methods for sensitive detection of sulfur ions (S^2- ). Based on luminescence resonance energy transfer (LRET) theory, we report the construction of a near-infrared (NIR) excitation luminescence probe using NaGdF₄ :Yb³⁺ ,Er³⁺ @NaYF₄ upconversion nanoparticles (UCNPs) as the donor and dye-670 as the receptor for detection of S^2- . When UCNPs and dye-670 molecules were combined using ligand exchange and electrostatic attraction, LRET occurred and UCNP luminescence was quenched. When S^2- was added to the system, sulfide ions were able to destroy the double bond of the dye, inhibiting LRET and restoring UCNP luminescence. Under optimum condition, the linear range of S^2- detection was 0.65-18.2 μM, and the detection limit was 34.2 nM. This method was applied for determination of S^2- in water with satisfactory results.