Surface-enhanced resonance-Raman scattering (SERRS) experiments using a citrate-coated silver colloid have been performed. Transmission electron microscopy showed that the colloid consists of nearly mondisperse hexagonal particles with a maximum dimension of 36 nm. For maximum sensitivity, SERRS requires the controlled aggregation of the colloid. The nature of the aggregate formed is dependent on the method of aggregation. The effect of poly-L-lysine on the aggregation procedure was characterised using transmission and scanning electron microscopy. With SERRS, sensitivities down to 6.87 × 10–18 mol dm–3 were obtained using rhodamine dye. This corresponds to less than 200 molecules in the beam at any one time and suggests a sensitivity equal to or greater than that of fluorescence. A comparison of the use of SERRS with surface-enhanced Raman scattering (SERS) to follow adsorbate reactivity on a surface at less than monolayer coverage was obtained by studying metal complex formation using a preresonant Schiff base (SERRS) and 2-hydroxy-1-naphthaldehyde excited off resonance (SERS). In the former case, complex formation on the surface at well below monolayer coverage was observed and differences between the surface and the bulk complex characterised. In the latter complex formation was again observed but the bands were broad and problems of contamination, photodecomposition and selectivity evident.
使用
柠檬酸盐涂层
银胶体进行表面增强共振拉曼散射(
SERRS)实验。透射电镜显示胶体由近单分散的六方颗粒组成,最大尺寸为36 nm。为了获得最大灵敏度,
SERRS 需要控制胶体的聚集。形成的聚集体的性质取决于聚集方法。使用透射和扫描电子显微镜表征聚-
L-赖氨酸对聚集过程的影响。借助
SERRS,使用
罗丹明染料可获得低至 6.87 × 10–18 mol dm–3 的灵敏度。这对应于任意时刻光束中的分子少于 200 个,表明灵敏度等于或大于荧光的灵敏度。通过使用预共振希夫碱 (
SERRS) 和 2-羟基-1- 来研究
金属配合物的形成,对使用
SERRS 与表面增强拉曼散射 (
SERS) 来追踪表面上小于单层覆盖的吸附物反应性进行了比较。
萘醛激发共振(
SERS)。在前一种情况下,观察到表面上远低于单层覆盖率的复合物形成,并表征了表面和本体复合物之间的差异。在后者中再次观察到复合物形成,但谱带很宽并且污染、光分解和选择性问题明显。