Synergistic catalysis by gold nanoparticles and metal ions for enhanced chemiluminescence

Abstract

We studied the synergistic effect of alkali metal ions and gold nanoparticles (AuNPs) on luminol-H₂O₂ chemiluminescence (CL). It was observed that alkali metal ions can independently enhance CL in presence (synergistic effect) and absence (individual effect) of AuNPs. The usual practice of using salts for aggregation has allowed very less opportunities for uncoupling and exploring the individual effects of AuNPs and salts in CL assays. Such studies, providing an innovative insight into their individual and combined role in luminol-H₂O₂ CL enhancement, have not been attempted before. After complete aggregation of nanoparticles, further increase in salt concentration enhanced signals, proving that aggregation is not the sole reason for CL amplification. Among the studied salts and alkalis, sodium chloride showed highest increase (600% over control) in synergy. The exact mechanism of catalysis and enhancement needs further investigation. This principle has the potential to increase overall quantum yield of CL, enabling design of highly sensitive analytical techniques.