Abstract:

In CH₃COONa-HCl buffer solution, ClO₂ ^- oxidizes excess I^- to generate I₃ ^-, and I₃ ^- forms complex particles with positively charged methylene blue under electrostatic attraction, which enhances the resonance scattering intensity of the system. Based on this principle, a new method for the determination of trace NaClO₂ in water by resonance scattering spectroscopy was established.The measurement conditions of this method were optimized to improve the resonance scattering intensity. The optimal dosage of CH₃COONa-HCl buffer solution, KI solution, and methylene blue solution, as well as the optimal reaction time and measurement wavelength, were obtained during the measurement. Under the optimal conditions, the resonance scattering intensity increased with the increase of ClO₂ ^- mass concentration in the range of 0.018 2-0.364 0 mg/L, which showed a good linear relationship with a detection limit of 0.004 8 mg/L. When this method was used to determine the content of chlorite in groundwater, the relative standard deviation of the measurement results was 1.5%-2.9%, and the recovery rate was 96%-99%.

Key words: chlorite, methylene blue, resonance scattering spectroscopy, associated particles

摘要：

在CH₃COONa-HCl缓冲溶液中，ClO₂ ^-氧化过量的I^-生成I₃ ^-，I₃ ^-与带正电荷的亚甲基蓝在静电引力作用下形成缔合物微粒，使体系的共振散射强度增强，据此建立测定水中痕量NaClO₂的共振散射光谱新方法。以提高共振散射强度为目标对该方法的测定条件进行了优化，获得了测定时CH₃COONa-HCl缓冲溶液、KI溶液、亚甲基蓝溶液的最佳用量及最佳的反应时间和测定波长。在最佳测定条件下，共振散射强度在ClO₂ ^-质量浓度0.018 2~0.364 0 mg/L范围内随其增大而增强，二者呈现良好的线性关系，检出限为0.004 8 mg/L。该方法用于测定地下水中ClO₂ ^-的含量时，测定结果的相对标准偏差为1.5%~2.9%，回收率为96%~99%。

关键词: 亚氯酸根, 亚甲基蓝, 共振散射光谱法, 缔合微粒

CLC Number: 

• X703