Resonance Scattering Effect of Rhodamine Dye Association Nanoparticles and Its Application to Respective Determination of Trace ClO2 and Cl2

• Published in: Environmental science & technology 2006-07, Vol.40 (13), p.4286-4291
• Main Authors: Jiang, Zhi-Liang, Zhou, Su-Mei, Liang, Ai-Hui, Kang, Caiyan, He, Xingcun
• Format: Article
• Language: English
• Subjects: Analytical chemistry; Applied sciences; Chemistry; Chlorine; Chlorine - analysis; Chlorine - chemistry; Chlorine Compounds - analysis; Chlorine Compounds - chemistry; Dimethyl Sulfoxide; Drinking water; Drinking water and swimming-pool water. Desalination; Dyes; Exact sciences and technology; Fluorescent Dyes - chemistry; Hydrogen-Ion Concentration; Indicators and Reagents - chemistry; Nanoparticles; Nanoparticles - chemistry; Oxides - analysis; Oxides - chemistry; Pollution; Potassium Iodide - chemistry; Rhodamines - chemistry; Spectrometric and optical methods; Spectrometry, Fluorescence; Water pollution; Water Purification; Water treatment and pollution
• ISSN: 0013-936X; 1520-5851
• DOI: 10.1021/es051949u

A new resonance scattering method, based on resonance scattering (RS) effect, for the respective determination of ClO2 and Cl2 in water samples was developed. In HCl−NaAc buffer solutions with the pH value of 1.42, chlorine dioxide, or chlorine, oxidizes I- to form I2, which then reacts with the excess I- to form I3 -. The resulting I3 - would combine, respectively, with four rhodamine(Rh) dyes, including rhodamine B (RhB), butyl rhodamine B (b−RhB), rhodamine 6G (RhG), and rhodamine S (RhS), to form association particles which exhibit a stronger resonance scattering (RS) effect at 420 nm. For four systems of RhB, bRhB, RhG, and RhS, chlorine dioxide was, respectively, determined in the concentration range of 0.0056∼0.787 mg/L, 0.0034∼0.396 mg/L, 0.0057∼0.795 mg/L, and 0.0052∼0.313 mg/L, with the detection limits of 0.0011 mg/L, 0.006 mg/L, 0.0054 mg/L, and 0.0023 mg/L ClO2, respectively. At the same experimental conditions as those for the determination of ClO2, chlorine was, respectively, determined in the concentration range of 0.013∼0.784 mg/L, 0.0136∼0.522 mg/L, 0.014∼0.81 mg/L, and 0.014∼0.42 mg/L, with the detection limits of 0.0016 mg/L, 0.0104 mg/L, 0.0079 mg/L, and 0.0037 mg/L Cl2, respectively. The total RS value originally from ClO2 and Cl2 was recorded in the buffer solution, while the RS value from ClO2 was obtained by using dimethyl sulfoxide to mask chlorine. Thus the RS value of chlorine was calculated by deducting the RS value of chlorine dioxide from the total RS value. The RhB RS method was chosen for the determination of ClO2 and Cl2 in drinking water, with advantages of high sensitivity, good selectivity, simplicity, rapidity, and convenience.