Determination of traces of bismuth by quenching of solid-substrate room-temperature phosphorescence from morin-labeled silicon dioxide nano-particles

Abstract

Silicon dioxide nano-particles, diameter 50 nm, containing morin (morin–SiO₂) have been synthesized by the sol–gel method. They emit strong and stable room-temperature phosphorescence (SS-RTP) on filter paper as substrate, and bismuth can quench the intensity of the SS-RTP. On this basis a new morin–SiO₂ solid-substrate room-temperature phosphorescence-quenching method has been established for determination of traces of bismuth. Reduction of phosphorescence intensity (ΔI_p) is directly proportional to the concentration of bismuth in the working range 0.16–14.4 ag spot⁻¹ (sample volume 0.40 μL spot⁻¹, corresponding to the concentration range 0.40–36.0 fg mL⁻¹). The regression equation of the working curve is ΔI_p=14.86+5.279×[Bi³⁺] (ag spot⁻¹) (n=6, r=0.9982). The detection limit of this method is 0.026 ag spot⁻¹ (corresponding to a concentration of 6.5×10⁻¹⁷ g mL⁻¹).This sensitive, reproducible and accurate method has been used for successful analysis of real samples.