Long‐lived electrochemiluminescence of ruthenium (II) complexes/tri‐n‐propylamine in aqueous solutions

Although the clinical use of immunoassays based on the oxidative‐reduction electrochemiluminescence (ECL) of tris(2,2′‐bipyridine)ruthenium (II)/tri‐n‐propylamine has been a great success, elucidation of the ECL generation mechanism still remains unsatisfactory. We report here our experimental observations of long‐lived luminescence that remains detectable for several seconds after termination of electrochemical heterogeneous oxidation. Long‐lived luminescence was observed in both a surfactant‐free buffer and a surfactant‐containing broadly used commercial buffer under different conditions. The slow decay of emission seems to have been unnoticed in previous ECL mechanistic studies. Within the frame of the reaction schemes so far proposed, its origin is inconclusively ascribed to the reductive‐oxidation process of ruthenium (II) complex, that is Ru(bpy)₃²⁺ → Ru(bpy)₃¹⁺ → Ru(bpy)₃²⁺* → Ru(bpy)₃²⁺ with the involvement of the tri‐n‐propylamine‐derived radical cation. It is anticipated that long‐lived ECL will suggest a research approach to separate some homogeneous reactions from the complicated reaction system and therefore help to resolve the mechanistic mystery.     

Investigations of the kinetic energy parameters of irradiated (La)‐doped phosphate glass

The current study characterizes and analyzes glow curves obtained from phosphate glass doped with different concentrations of lanthanum. Kinetic parameters of the glow curves obtained from beta‐irradiated phosphate glass samples doped with lanthanum were determined using a newly designed deconvoluted software. The obtained results from the analyses indicated that the glow curves of the phosphate glass samples were composed of five overlapping peaks. The activation energies of the five electron traps were located between 0.622 and 1.133 eV. The obtained kinetic parameters were evaluated using the designed software and another two methods and all revealed good agreement. The first three traps displayed non‐first‐order behaviour, while the two deep traps obeyed nearly first‐order kinetics.     

New bioluminescence pyrophosphate assay for high‐sensitivity detection of food‐borne pathogens

Traditional methods of identifying food‐borne pathogens are time consuming and laborious, so innovative methods for their rapid identification must be developed. Testing for bioluminescence pyrophosphate is a convenient and fast method of detecting pathogens without complex equipment. However, the sensitivity of the method is not as high as that of other methods, and it has a very high detection limit. In this study, the method was optimized to improve its sensitivity. The shortcomings of the method were first identified and corrected using dATPαS instead of dATP for the polymerase chain reaction (PCR), therefore reducing the background signal. Also, when the DNA template extracted from the food‐borne pathogens was purified, the new bioluminescence pyrophosphate assay had a limit of detection of <10 copy/μl or 10 colony‐forming units/ml, and its sensitivity was higher than that of fluorescent real‐time quantitative PCR. Moreover, a single copy of a food‐borne pathogen could be detected when a single DNA template was included in the PCR. Salmonella was detected in and isolated from 60 samples of broiler chicken, and the accuracy of the results was verified using a culture method (GB 4789.4–2010). These results showed that the new bioluminescence pyrophosphate assay has the advantages of an intuitive detection process, convenient operation, and rapid measurements. Therefore, it can be used for the rapid detection of pathogenic bacteria and probiotics in various fields.