银纳米粒子探针等离子共振散射光谱法测定抗坏血酸

利用抗坏血酸(VC)还原银氨溶液生成具有强烈等离子体共振散射特性的银纳米粒子，导致体系共振光散射信号的增强，散射最大峰位于544 nm。 在最佳条件下，体系的共振散射强度与抗坏血酸浓度在0.2~7.0 μmol/L范围内呈线性关系，相关系数为0.9988，检出限为8.1 nmol/L。 抗坏血酸的氧化产物能与银纳米粒子相互作用使之分散均匀且保持稳定，因此该体系不需要添加稳定剂或分散剂。 以此建立了用银纳米粒子为探针的测定抗坏血酸的高灵敏、简捷的共振散射新方法。 同时讨论了最佳反应条件和其它影响因素。 该方法用于ＶＣ片及饮料中抗坏血酸的测定，加标回收率在94.5%~97.0%之间。 结果表明，方法具有操作简单，灵敏度高和回收率较好等优点。

Detection of Ascorbic Acid Using the Plasmonic Resonance Light Scattering Method Based on Silver Nanoparticle Probe

A resonance light scattering detection method of ascorbic acid is reported based on the formation of silver nanoparticles(NPs). Ascorbic scid(vitamin C,VC)) could reduce Ag(NH3)+2 to form the silver nanoparticles, resulting in strong plasmon resonance light scattering(PRLS) signals characterized at 544 nm, which could be measured using a common spectrofluorometer. It is found that the PRLS intensities were proportional to the ascorbic acid concentrations in the range of 0.2~7.0 μmol/L with R2=0.9988 and detection limit(3σ/k) of 8.1×10-9 mol/L. The presence of a physically adsorbed layer of the product of the redox reaction on the surface of colloidal silver could prevent irreversible aggregation of silver NPs. The conditions of the reaction and the interference of the common ions are investigated. For the determination of ascorbic acid in VC tablets and beverage samples, the recovery was within the range of 94.5%~97.0%. Results suggested that the method possessed easy of implementation, high sensitivity, and better recovery, and so on.