Peng Ruiqi, Guo Lei, Chen Lu, Liu Lulu, Deng Wei, Li Dan
School of Chemical and Environmental Engineering, Shanghai Institute of Technology, 100 Haiquan Road, Shanghai 201418, P. R. China.
Anal Chem. 2024 Sep 5. doi: 10.1021/acs.analchem.4c01519.
Surface-enhanced Raman scattering (SERS) sensing of racemates is a remarkably fascinating yet very sophisticated objective because of similar physicochemical features of enantiomers. Inspired by the enantiomeric selectivity of nucleophilic addition reaction (NAR) toward amino acids, we herein propose highly effective, robust SERS discrimination of d- and l-valine by synergizing asymmetric gold nanorods-embedded ZIF-8 nanoparticles (AGNZ) with NAR to engender stereoselective molecular fingerprint. Experimental and chemometric analyses disclose that enantioselectivity lies in dual aspects: (i) abundant interfacial cavities and 3D hot-spots in AGNZ offer necessary confined asymmetrical surroundings to trigger enantiospecific molecular adsorption and interaction affinity, and (ii) the specified NAR drags the racemates adjacent to the interfacial area of AGNZ for maximum analytes-substrate interaction. This strategy is universal and can be utilized for the recognition of different amino acid enantiomers. Importantly, multiple quantifications of the racemic ratio can be realized with superior prognostic performances. This synergizing strategy therefore provides a significant paradigm shift from traditional methods to realize highly effective SERS discrimination of racemates.
由于对映体具有相似的物理化学特性，外消旋体的表面增强拉曼散射（SERS）传感是一个极具吸引力但又非常复杂的目标。受亲核加成反应（NAR）对氨基酸的对映体选择性启发，我们在此提出通过将嵌入不对称金纳米棒的ZIF-8纳米颗粒（AGNZ）与NAR协同作用，以产生立体选择性分子指纹，从而实现对d-缬氨酸和l-缬氨酸的高效、稳健的SERS鉴别。实验和化学计量分析表明，对映体选择性体现在两个方面：（i）AGNZ中丰富的界面腔和三维热点提供了必要的受限不对称环境，以触发对映体特异性分子吸附和相互作用亲和力；（ii）特定的NAR将外消旋体拖到AGNZ的界面区域附近，以实现最大程度的分析物-底物相互作用。该策略具有通用性，可用于识别不同的氨基酸对映体。重要的是，可以实现外消旋比的多重定量，并具有优异的预测性能。因此，这种协同策略提供了从传统方法到实现对外消旋体高效SERS鉴别的重大范式转变。
