全氟辛烷磺酸高灵敏共振光散射分析测定

Highly Sensitive Detection of Perfluorooctane Sulfonate by Resonance Light Scattering Technique

在pH值为2．87的Britton—Robinson（BR）缓冲溶液中，全氟辛烷磺酸（PFOS）可通过静电相互作用与质子化的乙基紫（EV）结合生成离子缔合物，导致体系散射信号显著增强．增强的散射信号（△IRLS）与PFOS浓度在一定范围内具有线性关系，据此建立了PFOS的共振光散射（Resonance Light Scattering，RLS）分析方法，线性范围为0．02～10．0μmol／L，检测限为2．0nmol／L．表征了紫外／可见光谱、扫描电镜显微成像（sEM），优化了实验条件，并探讨了反应机理．该方法成功地用于三峡库区嘉陵江水样中PFOS的测定，相树标准误差小于等于4．5％．

A highly sensitive assay of perfluorooctane sulfonate （PFOS） is proposed based on the fact that PFOS can react with protonated ethyl violet （EV） by electrostatic interactions and produce ion-association complexes in pH 2.87 Britton-Robinson （BR） buffer solution. The interaction leads to a great enhance ment of resonance light scattering （RLS） intensities, which is characterized by peaks at 326 nm and 503 nm. It is found that the enhanced RLS intensity at 326 nm is proportional to the concentration of PFOS in a range of 0. 02 /~mol/L to 10.0 pmol/L, with a limit of detection of 2.0 nrnol/L. In addition, UV/Vis ab- sorption spectrum and scanning electron microscope （SEM） images are both investigated to further vali- date the reaction mechanism. The interference of coexisting foreign substances and the optimum tests of reaction conditions, including pH value, reaction time and ionic strength, are also investigated. The method proposed has been successfully applied to the determination of PFOS in the environmental water sample of the Jialing River, RSD （relative standard deviation） being ≤4.5%.