Inhibition of rhodamine B-ferricyanide chemiluminescence by Au nanoparticles toward the sensitive determination of mercury (II) ions

A new high sensitive, selective, and simple method based on the inhibited effect of gold nanoparticles (Au NPs) on rhodamine B (RB)-ferricyanide (Fe(CN)63 −) chemiluminescence (CL) system has been developed for the determination of Hg2 + in environmental samples. This study is the analytical exploiting of Au NPs inhibiting effect on CL system. RB-Fe(CN)63 − causes a high emission intensity in alkaline condition but undergoes an intense extinction in the presence of Au NPs. This decreasing effect can be attributed to the energy transfer and collisions between RB molecules and Au NPs. Moreover, it is observed that the CL intensity is gradually restored in the presence of mercury (II) due to RB molecules release from the surfaces of Au NPs. Based on this effect, sensitive, and selective turn-on CL assay was developed for the determination of Hg2 +. Under the optimized conditions, CL calibration curve was drawn as a function of Hg2 + concentration, which is linear over the range of 0.013-4.67 μg L− 1 (0.067-23.3 nmol L− 1) with limit of detection (3s) and quantification (10s) of 5.42 and 18 ng L− 1, respectively. The relative standard deviations (RSD%, n = 5) were about 0.7-2.1% for the different concentrations of Hg2 +. The presented assay was satisfactorily applied to the quantification of Hg2 + in the environmental (tap, rain, and river) water samples, which shows good sensitivity and reliability in comparison with the other nanoparticle-based methods; the recoveries were 97-102%.