A novel, simple and sensitive resonance scattering spectral method for the determination of chlorite in water by means of rhodamine B

A new resonance scattering method was proposed for the determination of chlorite, basing on the resonance scattering effect of rhodamine dye. In HCl-sodium acetate buffer solution, chlorite oxidizes I− into I2 and the reaction of I2 and excess I− results in I3−. It is respectively combined with rhodamine dyes, including rhodamine B (RhB), butyl rhodamine B (b-RhB), rhodamine G (RhG) and rhodamine S (RhS), to form association complex particles, which exhibit stronger resonance scattering (RS) effect at 400 nm. The chlorite concentration of ClO2− in the range of 0.00726—0.218 μg/ml, 0.0102—0.292 μg/ml, 0.00726—0.145 μg/ml and 0.0290—0.174 μg/ml is respectively linear to the RS intensity of association complex particle systems at 400 nm for the RhB, b-RhB, RhG and RhS. The detection limits of the four systems were respectively 0.00436, 0.00652, 0.00580 and 0.01450 μg/ml ClO2−. In the four systems, the RhB system possesses good stability and high sensitivity. It has been applied to the analysis of chlorite in wastewater with satisfactory results.