表面增强拉曼光谱法灵敏检测亚硫酸根离子

通过可控自组装途径，开发一种基于4-巯基苯硼酸（4-mercaptoboric acid，4-MPBA）探针的表面增强拉曼散射（surface-enhanced Raman scattering，SERS）芯片的超灵敏亚硫酸根离子（SO32－）定量技术。该技术借助SO32－到SO42－的氧化转化特性，利用Lewis酸碱配位原理，建立基于特征峰1 382 cm－1与1 070 cm－1的比率型定量检测方程。该比率定量策略排除了SERS基底不均匀导致的检测误差，有效提高检测信号获取的可靠性，检出限低至5×10－8 mol/L，并在5×10－8～1×10－3 mol/L的浓度范围内呈良好线性关系（R2＝0.997 4）。检测到白糖中SO32－含量为1.42 mg/kg，加标回收率在98.38%～107.82%之间，说明该方法对于实际样品中SO32－的痕量检测具有极大优势。

Sensitive Detection of Sulfite Ions by Surface-Enhanced Raman Spectroscopy

In this work, a surface-enhanced Raman scattering (SERS) chip based on 4-mercaptoboric acid (4-MPBA) probe was developed by controllable self-assembly for the ultrasensitive quantitation of SO32-. This technique was based on the oxidative transformation of SO32- to SO42- and the Lewis acid-base coordination principle. The quantitative detection of SO32- was based on the ratio of the intensity of the peak at 1 382 cm-1 to that at 1 070 cm-1 (I1 382/I1 070). This ratiometric quantification strategy avoided errors caused by the inhomogeneity of SERS substrates, and effectively improved the reliability of detection signals. The limit of detection (LOD) of this SERS chip was as low as 5 × 10-8 mol/L, and a good linear relationship was obtained over the concentration range of 5 × 10-8 –1 × 10-3 mol/L (R2 = 0.997 4). Using this method, the SO32- content in white sugar was determined to be 1.42 mg/kg and recoveries for spiked white sugar were 98.38%–107.82%, suggesting that this method has good application prospects for the rapid determination of trace levels of SO32- in actual samples.