摘要
In acid medium, rhodamine B（RhB）, rhodamine S（RhS）, rhodamine 6G（RhG） and butyl rhodamine B（b-RhB） have a fluorescence peak at 580, 549, 553 and 580nm, respectively. BrO^-3 oxidizes excess I^- into I^-3 Rhodamine dyes combine I^-3 to form ion association nanoparticles, resulting in fluorescence quenching at 580, 549, 553 and 580 rim, respectively. The fluorescence quenching intensity is proportional to the concentration of BrO^-3 in the range of 0.020 4 - 0.710 μg/mL for RhB, 0.025 - 0. 512μg/mL for RhS, 0.025 - 0.260 μg/mL for RhG, 0.025 - 1.28μg/mL for b-RhB, respectively. In the four systems, RhB system has good stability and high sensitivity. Thus, a simple, sensitive fluorescence method was proposed for the determination of BrO^-3 in commercial bread additives and flours, with satisfactory results. The results of the fluorescence spectra and scan electron microscopy show that the formation of about 60 ran （RhB - I^-3） n association nanoparticles and the interface between the nanoparticles and solution are main factors that cause the fluorescence quenching.
In acid medium, rhodamine B（RhB）, rhodamine S（RhS）, rhodamine 6G（RhG） and butyl rhodamine B（b-RhB） have a fluorescence peak at 580, 549, 553 and 580 nm , respectively. BrO-3 oxidizes excess I- into I-3. Rhodamine dyes combine I-3 to form ion association nanoparticles, resulting in fluorescence quenching at 580, 549, 553 and 580 nm, respectively. The fluorescence quenching intensity is proportional to the concentration of BrO-3 in the range of 0.020 40.710 μg/mL for RhB, 0.0250.512 μg/mL for RhS, 0.0250.260 μg/mL for RhG, 0.0251.28 μg/mL for b-RhB, respectively. In the four systems, RhB system has good stability and high sensitivity. Thus, a simple, sensitive fluorescence method was proposed for the determination of BrO-3 in commercial bread additives and flours, with satisfactory results. The results of the fluorescence spectra and scan electron microscopy show that the formation of about 60 nm （RhB-I3）n association nanoparticles and the interface between the nanoparticles and solution are main factors that cause the fluorescence quenching.
