金纳米棒由于其独特的物理、化学性质成为了分析化学领域研究的热点。本论文以亚铜试剂Cu(NC)₂²⁺为金纳米棒刻蚀剂，以十六烷基三甲基溴化铵（CTAB）为纳米棒分散剂，在混合刻蚀体系中，金纳米棒被Cu(NC)₂²⁺沿着纵向缓慢刻蚀变短，进而引起纵向局部等离子体共振吸收峰波长蓝移；另一方面，由于Cu(NC)₂²⁺被还原为Cu(NC)₂⁺，在450 nm处产生吸收峰。加入抗氧化剂后，Cu(NC)₂²⁺络合物优先与抗氧化剂反应，进而抑制了金纳米棒的刻蚀，使得纵向局部等离子体共振吸收峰波长蓝移程度减弱，同时450 nm处的吸光度增强，基于此建立波长位移和吸光度的双模式检测方法。本研究对该方法的干扰能力进行分析，并测定决明子提取液的总抗氧化能力。

Gold nanoparticles have become a hotspot in analytical chemistry due to its unique physical and chemical properties. In this thesis, Cu(NC)₂²⁺ is used as the gold nanorod etchant, and cetyltrimethylammonium bromide (CTAB) is used as the gold nanorod dispersant. In the mixed etching system, the gold nanorods are slowly etched by Cu(NC)₂²⁺ along the longitudinal direction, which in turn causes the blue shift of the L-LSPR band; meanwhile, reduction of Cu(NC)₂²⁺ produces Cu(NC)₂⁺, which generates a higher absorbance at 450 nm. With the addition of antioxidants, however, the Cu(NC)₂²⁺ complex preferentially reacts with the antioxidants, thereby inhibiting the etching of the gold nanorods. Therefore, the blue shift of the L-LSPR band is decreased, and the absorbance at 450 nm is enhanced. Based on this mechanism, a dual-mode detection method for colorimetric detection of antioxidants based on wavelength shift and absorbance is established. The interference capacity of the method was evaluated, and the total antioxidant capacity of the extract of Semen Cassiae was determined.