A turn-off-on near-infrared photoluminescence sensor for sequential detection of Fe3+ and ascorbic acid based on glutathione-capped gold nanoclusters

Many reports have suggested that near-infrared (NIR) fluorescent probes are one of the most promising molecules for improving the sensitivity of fluorescence sensing and imaging. Herein, gold nanoclusters with excellent near-infrared photoluminescence (PL) were synthesized by a simply hydrothermal treatment of hydrogen tetrachloroaurate(III) trihydrate and glutathione (GSH). The NIR PL of GSH-capped gold nanoclusters (GSH-AuNCs) can be significantly quenched by Fe 3+ , which follows a dynamic quenching mechanism. However, the NIR PL of the GSH-AuNCs/Fe 3+ system can be recovered after the addition of ascorbic acid (AA). The decrease and increase of NIR PL intensities of GSH-AuNCs were linearly correlated with the concentration of Fe 3+ and AA, respectively. Therefore, a turn-off-on NIR PL sensing strategy can be constructed for sequential detection of Fe 3+ and AA with the linear range of 0.7–180 μM and 0.5–120 μM, respectively. The proposed NIR PL sensor exhibits excellent sensing performance and has been applied to the determination of Fe 3+ and AA in real samples with satisfactory results.