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Here, we developed a novel electrochemiluminescence resonance energy transfer (ECL-RET) approach between Ru(bpy)32+and Au nanorods (NRs) for sensitive determination of H2O2. Au NRs were synthesized through silver ion-assisted seed-mediated method which exhibited an obvious absorption peak at about 627 nm. They were modified at glassy carbon electrode (GCE) surface which showed a significant ECL quenching efficiency about 56.5% due to the ECL-RET process. This Au NRs modified electrode was then utilized to measure the concentration of H2O2on the basis of the significant quenching effect of H2O2on Ru(bpy)32+ECL. Results demonstrated that the decrement of ECL intensity at Au NRs modified electrode had ~ 6.6-fold enhancement as compared with that at bare electrode.

Electrochemical oxidation with boron-doped diamond (BDD) had been well established as an outstanding technology for wastewater treatment. In this study, BDD technology was initially used to degrade direct blue 71 (DB71) dye under galvanostatic conditions. The main and joint effects of three operating parameters (supporting electrolyte concentration, applied current density and flow rate) on oxidation performance were estimated by Box-Behnken design. Among the variables, sulfate concentration displayed the most unique roles in DB71 degradation. The optimum operating conditions obtained by response surface methodology were: 2.0 mM Na2SO4, applied current density of 7.75 mM cm−2and flow rate of 600 mL min−1, which gave a decolorization percentage of 100%, a mineralization percentage of 50.2%, as well as an energy consumption of 3845 kWh kg−1TOC and a mineralization efficiency of 8.7% at 120 min of electrolysis. In addition, based on the quantum chemistry calculation and identified reaction intermediates detected by LC/MS analysis, a plausible degradation sequence of DB71 in BDD anode cells was also proposed. The results obtained were expected to offer useful guidance for the application of BDD technology as powerful and green option for treating DB71 pollutants.

A novel buoyant force-propelled micromotor is designed by decorating bimetallic catalysts (Ag and Pt NPs) on glassy carbon bead matrix for high efficient removal of organic pollutant via advanced oxidation processes. The micromotor floats to the top of solution when enough number of bubbles are accumulated on its surface and then sinks to the bottom after the evolution of bubbles. Owing to the excellent catalytic effect of Ag and Pt NPs, oxygen bubble generation and evolution frequencies are improved, leading to the ultra-fast movement of micromotor in H2O2solution with a long lifetime of 6 h and a highest speed of ca. 12 mm/s. Meanwhile, active radical species are produced in the reaction of Ag NPs and H2O2. As a result, the synergy effect of vigorous intermixing and peroxidase mimics activity of Ag NPs speeds up the degradation significantly. In order to improve the decontamination efficiency, key factors that affect the motion performance and the generation of ROS, including H2O2, sodium dodecyl sulfate, buffer solution and the amount of micromotors, are discussed using response surface methodology. Taking methylene blue (MB) as pollutant model, the degradation rate increased from 32.47% to 90.42% after the deposition of Pt NPs on Ag micromotor, indicating the excellent catalytic effect of the bimetallic catalysts modified micromotor. Possible degradation pathway of MB was proposed, based on the results of quantum chemistry calculation and LC/MS analysis. Overall, the ultra-high traveling speed and the excellent catalytic effect make it to be a promise candidate for environmental remediation.

Abstract: An electrochemiluminescent (ECL) biosensor was constructed for selective assay of alanine aminotransferase (ALT) based on the enzymatically catalyzed oxidation of pyruvate by pyruvate oxidase (PYOD). The composite of potassium ferricyanide and carbon nanotube was adopted to pre-functionalize the basal platinum electrode while the potassium ferricyanide acted as the activator of PYOD. The ALT catalyzed the reaction of L-alanine and α-ketoglutarate to produce pyruvate which could be further enzymatically oxidized by PYOD to yield H2O2 to intensify the ECL of luminol. The biosensor showed rapid response for real-time measurement of ALT in the linear concentration range from 0.00475 to 350 U/L (r = 0.993) with a relatively standard deviation of 2.5% (C ALT = 47.5 U/L, n = 6). The biosensor was applied to assay the ALT in rat serum with average recovery of 90.5%.