表面增强拉曼散射技术在快速检测预包装干米粉中乙二胺四乙酸二钠的应用

Application of Surface Enhanced Raman Scattering Spectroscopy in the Rapid Detection of Ethylenediaminetetraacetic Acid Disodium Salt in Prepackaged Dried Rice Noodles

利用简单的种子介导法制备Fe_(3)O_(4)@SiO_(2)@AgNPs作为表面增强拉曼散射基底,对预包装干米粉中的微量添加剂——乙二胺四乙酸二钠(ethylenediaminetetraacetic acid disodium salt,EDTA-2Na)含量进行快速灵敏的检测。通过透射电子显微镜、X射线能谱、X射线衍射、红外光谱以及表面增强拉曼散射(surface enhanced Raman scattering,SERS)对Fe3O4@SiO2@AgNPs进行表征,结果显示Fe_(3)O_(4)@SiO_(2)@AgNPs为直径约660 nm,大小均匀,核壳结构的磁性基底,测得罗丹明6G溶液的最低浓度为1×10^(-9)mol/L,增强因子为4.27×10^(8)。以Fe_(3)O_(4)@SiO_(2)@AgNPs为SERS基底对EDTA-2Na溶液进行SERS检测,检出限为1.75×10^(-6)mg/mL,以EDTA-2Na特征峰1 625 cm^(-1)的SERS强度为纵坐标,EDTA-2Na质量浓度的对数为横坐标进行线性回归拟合,结果表明EDTA-2Na质量浓度在1×10^(-5)~1 mg/mL范围内呈现良好的线性关系,R^(2)为0.994。将Fe_(3)O_(4)@SiO_(2)@AgNPs用于预包装干米粉中EDTA-2Na的快速检测,样品检出限为0.1 mg/kg,加标回收率为96.50%~104.67%,相对标准偏差为1.2%~4.2%,说明本方法可准确、灵敏、快速地检测预包装干米粉中是否过量添加EDTA-2Na。

Fe_(3)O_(4)@SiO_(2)@silver nanoparticles(AgNPs)were synthesized by a facile seed-mediated method and used as a surface enhanced Raman scattering(SERS)substrate to detect the content of the trace additive ethylenediaminetetraacetic acid disodium salt(EDTA-2Na)in prepackaged dried rice noodles.Fe_(3)O_(4)@SiO_(2)@AgNPs were characterized by transmission electron microscopy,X-ray energy spectroscopy,X-ray diffraction spectroscopy,infrared spectroscopy,and SERS spectroscopy.The results showed that Fe_(3)O_(4)@SiO_(2)@AgNPs were a magnetic substrate with a core-shell structure,and a diameter of about 660 nm.The minimum detectable concentration of rhodamine 6G(R6G)solution was measured to be 1×10^(-9) mol/L and the enhancement factor was 4.27×10^(8).The limit of detection(LOD)of EDTA-2Na solution using Fe_(3)O_(4)@SiO_(2)@AgNPs was 1.75×10^(-6) mg/mL.Good linearity was observed between the SERS intensity of the characteristic peak at 1625 cm^(-1) and the logarithmatic concentration of EDTA-2Na with a correlation coefficient(R^(2))of 0.994.The LOD was 0.1 mg/kg for EDTA-2Na in prepackaged dried rice noodles,and the recoveries for spiked samples were 96.50%-104.67%with relative standard deviation(RSD)of 1.2%-4.2%.Accordingly,this method can accurately,sensitively and rapidly detect whether EDTA-2Na is added in excess in prepackaged dried rice noodles.