Determination of Fe³⁺ upon Special "Upconversion Luminescence" of Dopamine.

ABSTRACT: A promising technique based on the luminescence with long wavelength excitation and short wavelength emission (LExL, ?_ex-L > ?_em) is developed. This LExL is different from traditional upconversion luminescence (UCL). The LExL, namely, special "UCL", is realized by a xenon light source of a common spectrofluorometer. In this work, we found that dopamine (DA) has this LExL phenomenon. The LExL of DA is mainly caused by the excitations of second-order diffraction light (?_ex-L/2). The two-photon absorption properties of DA have been calculated employing the density functional response theory. The LExL and Stokes luminescence (SL, ?_ex-S < ?_em) of DA both showed static quenching upon the addition of Fe³⁺. Dual-mode luminescence methods upon LExL (?_ex-L/?_em at 565/317 nm) and SL (?_ex-S/?_em at 282/317 nm) of DA were applied for the selective determination of Fe³⁺. The detection limits are 0.30 and 0.52 ?mol L^-1 for LExL and SL, respectively. In addition, their linear ranges for Fe³⁺ determination are both from 0.70 to 30 ?mol L^-1. The LExL method of DA not only meets the basic determination criteria for Fe³⁺ but also offers additional advantages in resisting more interferences and shows satisfactory feasibility performances.

SUBMITTER: Cui R 

PROVIDER: S-EPMC6648159 | biostudies-literature | 2019 Jun

REPOSITORIES: biostudies-literature