A novel chemiluminescent-based nano-probe for ultra-trace quantification of dopamine in human plasma samples

An innovative chemiluminescence (CL)-based nano-probe was established for dopamine quantification by the enhancement of luminol-KMnO4 CL signal using a layered nanomaterial. The intensity of the CL signal was amplified by 18-folds using nickel-aluminum layered double hydroxide (Ni-Al LDH). The possible enhancement mechanism of the CL system in the presence of the nano-structured Ni-Al-NO3 LDH was discussed. The improved signal was diminished in the presence of dopamine owing to its inhibitory influence on the performing of the CL reaction through the intercalation between the LDH layers. As decreasing in the CL signal was proportional with dopamine concentration, so an optical nano-probe was constructed for dopamine detection. Several factors affecting the CL signal such as concentrations of the luminol, KMnO4, NaOH, and LDH were optimized. In the optimal conditions, the CL approach demonstrated a linear response in the concentration range between 0.025 and 20 mu g L-1 with a detection limit of 6.5 ng L-1. The limit of quantification, the intra- and inter-day relative standard deviations (n = 6 and dopamine concentration; 5.0 mu g L-1) were 0.022 mu g L-1, 2.7% and 4.1%, respectively. The method was efficiently employed to assess dopamine in numerous human plasma samples with relative recovery values between 97.3 and 104.6% for the spiked samples.