Fluorescence Intensity Of Rhodamine B Research Articles

Gap-plasmon of Fe3O4@Ag core-shell nanostructures for highly enhanced fluorescence detection of Rhodamine B

A novel gap-plasmon of Fe3O4@Ag core-shell nanoparticles for surface enhanced fluorescence detection of Rhodamine B (RB) was developed. Fe3O4@Ag core-shell nanostructures with Ag shell and Fe3O4 core were synthetized by self-assembled method with the assistance of 3-mercaptopropyl trimethoxy silane (MPTS). To study the RB fluorescence enhanced by gap-plasmon, the fluorescence properties of RB on the substrates with different nanogap densities were systematically investigated, and the results showed that the fluorescence intensity of RB on Fe3O4@Ag core-shell NPs substrate was much stronger than that on bare glass substrate, and the fluorescence intensity was further improved by using multilayer Fe3O4@Ag core-shell NPs substrate which had higher nanogap density. Different from the mechanism that is based on the maximum overlap of the surface plasmon resonance (SPR) band and emission band, the mechanism of the fluorescence enhancement in our work is based on the localized surface plasmon (LSP) and the gap plasmon near-field coupling with the Fe3O4@Ag core-shell NPs. Besides, the detection limit obtained was as low as 1×10-7 mol/L, and the Fe3O4@Ag core-shell NPs substrate had high selectivity for RB fluorophores. It was demonstrated that the Fe3O4@Ag core-shell NPs substrate had activity, good stability, and selectivity for fluorescence detection of RB. And the detection of RB by the surface plasmon enhanced fluorescence was more convenient and rapid than the traditional detection methods in previous works.

Determination of L-Cysteine Based on Energy Transfer between Cu2-xSe Nanoparticles and Rhodamine B

Abstract The fluorescence of Rhodamine B (RhB) could be quenched by the manner of photo-induced electron transfer with Cu2-xSe nanoparticles as the energy receptor and RhB as the energy donor. However, L-cysteine (L-Cys) was capable of recovering the fluorescence of Rhodamine B, and the recovered fluorescence intensity was proportional to the concentrations of L-Cys. Based on that, a novel method for detecting L-Cys was established. After mixing L-Cys and RhB pretreated by Cu2-xSe nanoparticles at pH 4.6 and 30 °C for 2 min, a linear relationship was obtained between the fluorescence intensity of RhB at 575 nm and the concentrations of L-Cys in the range of 2.5 × 10−7−1.1 × 10−6 M. This method was used for the determination of L-cys with a detection limit (3σ/k) of 5.5 × 10−8 M. The common amino acids presented little interference for the detection of L-Cys.

Detection of melamine based on the fluorescence resonance energy transfer between CdTe QDs and Rhodamine B

In this paper, we constructed the fluorescence resonance energy transfer (FRET) system between MPA-capped CdTe quantum dots (QDs) and Rhodamine B (RB) in the environment of cetyltrimethylammonium bromide (CTAB). In this system, CdTe QDs were treated as energy donors, whilst RB was treated as energy acceptor. CTAB was used to make the distance between the particles of CdTe QDs and RB closer to improve the efficiency of FRET system. We optimized some important factors which would affect the efficiency of FRET system. Under the optimized experimental conditions, melamine (MB) could be detected based on the fluorescence intensity changes of RB in the FRET system. We could get a linear relationship between the fluorescence intensity of RB and the concentration of MB in the range of 0.05–4.0μmol/L and the detection limit was 0.01μmol/L. The proposed method was applied for the determination of melamine in milk samples with satisfactory results.

Fluorescence Resonance Energy Transfer Between Acridine Orange and Rhodamine B and Analytical Application on Determination of Vitamin B12

A new method to determine Vitamin B12 by applying energy transfer fluorescence quenching of Acridine orange (AO)–Rhodamine B (RB) has been studied and established. It was found that the effective energy transfer could occur between AO and RB at λex/λem=470/575 nm in the dodecyl benzene sodium sulfonate (DBS) and Na2HPO4–citric buffer (pH=7.0). The fluorescence intensity of RB increased sharply. Vitamin B12 diminished the fluorescence intensity of RB depending on the isochromacticity between them. The detection limit of the method was up to 1.5×10−7 mol L−1. The range of determining concentration of Vitamin B12 was 2.5×10−7∼8.0×10−6 mol L−1. The relative standard deviation was 1.93% for six parallel determinations of Vitamin B12. The recoveries of Vitamin B12 were 97∼101%. The method was applied to the determination of Vitamin B12 in injection.

Enhancement in the Fluorescence Intensity of Rhodamine-B by Some Surfactants

Enhancement in the Fluorescence Intensity of Rhodamine-B by Some Surfactants