CTMAB增敏共振瑞利散射法快速测定面制食品中的Pb

摘要

在表面活性剂溴化十六烷基三甲基铵及酸性三羟甲基氨基甲烷-盐酸缓冲介质存在条件下，铬天青S与Pb （Ⅱ）结合，导致共振瑞利散射（resonance Rayleigh scattering，RRS）显著增强，并产生新的RRS光谱。在最大共振瑞利散射峰369 nm波长处，Pb（Ⅱ）的质量浓度在0.002～0.35 mg/L范围内与体系的共振瑞利散射增强程度（ΔIRRS）呈良好的线性关系，定量限为0.024 mg/kg。据此建立了快速、准确、高灵敏的测定Pb（Ⅱ）的RRS新方法，并研究了适宜的反应条件及RRS光谱特征。方法可用于市售面制食品中Pb的快速测定。%In the presence of surfactant cetyl trimethyl ammonium bromide and an acidic Tris-hydrochloric acid buffer medium, chrome azurol S can be bound with lead (Ⅱ) to form a new product, which leads to a distinctly enhanced resonance Rayleigh scattering (RRS) and the appearance of a new RRS spectrum. The maximum RRS peak was located at 369 nm. The mass concentration of lead (Ⅱ) in the range of 0.002 to 0.35 mg/L was directly proportional to the RRS intensity (ΔIRRS) of system with the limit of quantitation (LOQ) being 0.024 mg/kg. Therefore, a rapid, accurate and sensitive new RRS method for quantifying lead (Ⅱ) was successfully developed. The optimal reaction conditions and resonance Rayleigh scattering spectral characteristics were investigated. The method can be used for rapid determination of lead in commercial pastas.