In recent years, surface-enhanced Raman spectroscopy (SERS) has been widely used in various fields for the rapid detection of trace-level molecular targets. In this study, we have developed a simple and effective solution-based SERS protocol to improve the activity for the detection of cationic dye molecules in aquaculture. The polystyrene sulfonate functionalized gold nanobipyramids (PSS–Au BPs) were synthesized from the cetyltrimethylammonium bromide (CTAB) reaction system followed by the ligand exchange process. The halide ions-induced aggregation of PSS-Au BPs was carried out by using four type of different salts such as NaCl, NaBr, MgCl₂ and MgSO₄ to investigate their influence on the SERS activity. The results demonstrate that the ionic strength of the solution has an important impact on the colloidal stability and SERS activity. The PSS-Au BPs show an improved SERS sensitivity at lower concentrations of the aggregating agents in solution-based SERS by detecting the crystal violet (CV) molecules with a limit of detection (LOD) to 3.28 × 10⁻¹¹ M. Furthermore, to demonstrate the generality of our proposed strategy, trace amounts of three more dyes such as malachite green (MG), methylene blue (MB), and rhodamine 6G (R-6G), as well as other molecules such as thiram and bisphenol-S were also detected. This protocol not only provides a method for rapid on-site detection of trace-level molecules but can also be applied to other SERS-based analysis.

近年来，表面增强拉曼光谱（SERS）已广泛应用于各个领域，用于快速检测痕量分子靶标。在这项研究中，我们开发了一种简单有效的基于溶液的 SERS 协议，以提高水产养殖中阳离子染料分子的检测活性。聚苯乙烯磺酸盐官能化金纳米双锥体 (PSS-Au BPs) 由十六烷基三甲基溴化铵 (CTAB) 反应体系和配体交换过程合成。卤化物离子诱导的 PSS-Au BPs 的聚集是通过使用 NaCl、NaBr、MgCl ₂和 MgSO _{4等四种不同的盐进行的。}调查它们对 SERS 活动的影响。结果表明，溶液的离子强度对胶体稳定性和SERS活性有重要影响。通过检测检测限 (LOD) 为 3.28 × 10 ^-11  M 的结晶紫 (CV) 分子，PSS-Au BP 在溶液型 SERS 中较低浓度的聚集剂下显示出改进的 SERS 灵敏度。此外，证明了我们提出的策略的普遍性，微量的另外三种染料，如孔雀石绿 (MG)、亚甲蓝 (MB) 和罗丹明 6G (R-6G)，以及其他分子，如福美双和双酚-S也检测到。该协议不仅提供了一种快速现场检测痕量分子的方法，还可以应用于其他基于 SERS 的分析。