维多利亚蓝B共振光散射法高灵敏选择性检测全氟辛烷磺酸

建立了一种用维多利亚蓝B(VBB)简便、高灵敏、选择性检测全氟辛烷磺酸(PFOS)的共振光散射(RLS)分析方法。在pH 6.0的KH₂PO₄-NaOH缓冲体系下，PFOS通过静电作用与质子化的VBB结合生成离子缔合物，在277 nm处的散射信号有明显的增强，增强的散射值(ΔI_RLS)与PFOS在一定浓度范围内有良好的线性关系，其线性方程为ΔI_RLS=72.28+336.53c (r=0.996 4)，线性范围为0.05~4.0 μmol·L-1，检测限为5.0 nmol·L-1。优化了实验条件，表征了紫外/可见吸收光谱、扫描电镜显微成像(SEM)，并探讨了作用机理。在相同实验条件下，考察了全氟辛酸(PFOA)及其他几种全氟化合物(PFCs)与VBB的相互作用，未见散射信号变化，因此，本法可实现对PFOS的选择性检测。该方法成功应用于检测环境水样中的PFOS，样品加标回收率为91.8%~100.6%，相对标准偏差RSD≤1.74%。

High Sensitive and Selective Detection of PFOS with Resonance Light Scattering Technology Based on the Interaction with Victoria Blue B

This report presents a simple,sensitive and selective victoria blue B (VBB)-b ased resonance light scattering (RLS) assay of perfluorooctane sulfonate (PFOS) .In pH 60 KH2PO4-NaOH buffer solution,VBB can be protonated and reacts with PFOS through electrostatic interactions to produce ionic-association complexes .Simultaneously,the interaction leads to enhanced resonance light scattering intensities greatly,which are characterized with a peak at 277 nm .It is found that the enhanced RLS intensity is proportional to the concentration of PFOS in a range of 005 to 40 μmol·L-1 .The limit of detection is 50 nmol·L-1 .While,under the optimal experimental conditions,almost no change of the resonance light scattering intensity was observed between VBB and perfluorooctane acid (PFOA) which is one kind of representative perfluorinated compounds (PFCs) .The excellent selectivity of PFOS could be due to the hydrophobicity of PFOS higher than PFOA .It is worth noting that the proposed method is cap able of differentiating PFOS and some other PFCs .UV/Vis absorption spectrum an d scanning electron microscope (SEM) image both were investigated to further validate the reaction mechanism .The interference of coexisting foreign substances and the optimum tests of reaction conditions,including pH value,reaction time,experimental temperature and ionic strength,were also investigated .This method has been successfully applied to the determination of PFOS in environmental water samples with RSD ≤1.74％ .The experimental process as followed: In 2 mL colorimetric tube,200 μL pH 60 KH2PO4-NaOH buffer solution,followed by adding 600 μL 20 μmol·L-1 VBB solution,swirl evenly,then ad d the right amount of PFOS solution .After vortex mixing with ultrapure water volume to 2 mL,swirl to mix,stand for 10 min at room temperature .Then the mixture was transferred for RLS measurements and absorption measurement .