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 Rhodam...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.展开更多
A new rhodamine derivative,N-(3-carboxy)acryloyl rhodamine B hydrazide(CARB),has been synthesized,and its unusual spectroscopic reaction with Cu2+ has been investigated.The derivative exhibits a rapid and reversible n...A new rhodamine derivative,N-(3-carboxy)acryloyl rhodamine B hydrazide(CARB),has been synthesized,and its unusual spectroscopic reaction with Cu2+ has been investigated.The derivative exhibits a rapid and reversible non-fluorescent absorption upon coordination to Cu2+,which is a rather unusual phenomenon for rhodamine B derivatives.Stoichiometric measurements using the Job's method and the molar ratio method reveal that one CARB molecule combines two Cu2+ ions,and the two Cu2+ ions play different roles:one opens the spirocyclic structure and the other quenches the fluorescence of the xanthene moiety.This reaction mechanism is supported by a comparative study on the model compound N-acryloyl rhodamine B hydrazide as well as by the density functional theory calculations.Furthermore,the absorption response of CARB is highly selective for Cu2+ over other common ions,which implies that CARB may be used as a colorimetric probe for the rapid visual detection of Cu2+.展开更多
文摘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.
基金supported by grants from the National Natural Science Foundation of China (20935005,90813032 & 20875092)National Basic Research Program of China (2010CB933502 & 2011CB935800)the Chinese Academy of Sciences
文摘A new rhodamine derivative,N-(3-carboxy)acryloyl rhodamine B hydrazide(CARB),has been synthesized,and its unusual spectroscopic reaction with Cu2+ has been investigated.The derivative exhibits a rapid and reversible non-fluorescent absorption upon coordination to Cu2+,which is a rather unusual phenomenon for rhodamine B derivatives.Stoichiometric measurements using the Job's method and the molar ratio method reveal that one CARB molecule combines two Cu2+ ions,and the two Cu2+ ions play different roles:one opens the spirocyclic structure and the other quenches the fluorescence of the xanthene moiety.This reaction mechanism is supported by a comparative study on the model compound N-acryloyl rhodamine B hydrazide as well as by the density functional theory calculations.Furthermore,the absorption response of CARB is highly selective for Cu2+ over other common ions,which implies that CARB may be used as a colorimetric probe for the rapid visual detection of Cu2+.