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 (S2- ). 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 S2- . When UCNPs and dye-670 molecules were combined using ligand exchange and electrostatic attraction, LRET occurred and UCNP luminescence was quenched. When S2- 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 S2- detection was 0.65-18.2 μM, and the detection limit was 34.2 nM. This method was applied for determination of S2- in water with satisfactory results.