A new method for determining lead by resonance Rayleigh scattering (RRS) has been proposed and its operation mechanism has been discussed. In pH 5.0 HAc–NaAc buffer solution, Pb(II) reacted with xylenol orange (XO) to form a chelating anion ([Pb (H₂In)] ^2–), which further reacted with crystal violet (CV) to form ternary ionic complexes, resulting in the enhancement of RRS intensity. The RRS intensity increases linearly with the concentration of Pb(II) in the range of 2.00 × 10^–3–2.00 × 10^–2 mg/L under optimal experimental conditions along with the detection limit of 9.2 × 10^–5 mg/L. This method is a promising approach for the selective and sensitive determination of Pb(II) in tea.

中文翻译：

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铅-二甲酚橙-结晶紫体系的共振瑞利散射光谱及其分析应用

提出了一种通过共振瑞利散射（RRS）测定铅的新方法，并讨论了其工作机理。在pH 5.0 HAc–NaAc缓冲溶液中，Pb（II）与二甲酚橙（XO）反应形成螯合阴离子（[Pb（H ₂ In）] ^2–），进一步与结晶紫（CV）反应形成三元阴离子离子络合物，导致RRS强度增强。在最佳实验条件下，RRS强度随Pb（II）浓度在2.00×10 ^–3 –2.00×10 ^–2 mg / L范围内线性增加，检出限为9.2×10 ^–5 mg / L。该方法是一种选择性，灵敏地测定茶叶中Pb（II）的方法。