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An electrochemiluminescence (ECL) method for determination of zinc ion has been developed based on the enhanced effects of zinc ion on the ECL system of Ru(phen) 3 2+ and phenanthroline (phen). The ECL intensity gradually increased with increasing zinc ion concentration under optimal condition. A linear regression equation (I ECL = 213.6lg[Zn 2+ ] + 7003.6; r = 0.99689, n = 5) was obtained over 1.0 × 10 −10 –1.0 × 10 −6 mol L −1 zinc ion, and the detection limit was as low as 1.0 × 10 −10 mol L −1 . For detection of 1.0 × 10 −10 , 1.0 × 10 −8 , and 1.0 × 10 −6 mol L −1 spiked zinc ion, the recovery ratio ranged from 101% to 103%, and the relative standard deviations were 2.10%, 0.97%, and 3.20%, respectively. These results demonstrated that the proposed method was effective and showed good reproducibility. [ABSTRACT FROM AUTHOR]

• A modified film electrode was first used for single-electrode electrochemiluminescence. • Ru(phen) 3 2+ modified CNT/graphene electrode has excellent long-term stability. • Dopamine can significantly quench electrochemiluminescence of triethylamine at Ru(phen) 3 2+ modified CNT/graphene electrode. • Sensitive visual detection of dopamine is achieved with a smartphone. A single-electrode electrochemical system (SEES) has been developed by attaching a plastic sticker with 24 holes onto tris(1,10-phenanthroline)ruthenium (Ru(phen) 3 2+) modified carbon nanotube (CNT)/graphene film electrode for the first time. The Ru(phen) 3 2+ modified CNT/graphene film electrode was fabricated by using CNT/graphene ink with the addition of Ru(phen) 3 2+. The immobilization of Ru(phen) 3 2+ is achieved through the π-π stacking interaction between Ru(phen) 3 2+ and CNT/graphene. The potential difference between the ends of cells in SEES is induced upon applying voltage because of the resistance of the Ru(phen) 3 2+ modified CNT/graphene film electrode, and triggers Ru(phen) 3 2+ electrochemiluminescence (ECL) reaction. By using a smart phone as the detector, visual ECL analysis of multiplex samples was achieved on this newly developed system. Dopamine (DA) can quench triethylamine ECL at Ru(phen) 3 2+ modified CNT/graphene film electrode, enabling visual DA detection. The visual DA detection demonstrates a good linearity in the range of 10−3–10 μM and 50–500 μM. The limit of detection is calculated as 1.9 nM at a signal-to-noise ratio of 3. The ECL system also exhibits excellent long-term stability after storage in the ambient environment for 60 days by comparing the ECL response with its original signal. [ABSTRACT FROM AUTHOR]

The concept and realization of microfluidic total analysis systems (microTAS) have revolutionized the analytical process by integrating the whole breadth of analytical techniques into miniaturized systems. Paramount for efficient and competitive microTAS are integrated detection strategies, which lead to low limits of detection while reducing the sample volume. The concept of electrochemiluminescence (ECL) has been intriguing ever since its introduction based on Ru(bpy)32+ by Tokel and Bard [1] (J Am Chem Soc 1853:2862–2863, 1972), especially because of its immense sensitivity, nonexistent auto-luminescent background signal, and simplicity in experimental design. Therefore, integrating ECL detection into microTAS is a logical consequence to achieve simple, yet highly sensitive, sensors. However, published microanalytical devices employing ECL detection focus in general on traditional ECL chemistry and have yet to take advantage of advances made in standard bench-top ECL strategies. This review will therefore focus on the most recent advancements in microfluidic ECL approaches, but also evaluate the potential impact of bench-top ECL research progress that would further improve performance and lower limits of detection of micro analytical ECL systems, ensuring their desirability as detection principle for microTAS applications. [ABSTRACT FROM AUTHOR]

Abstract: Carbon quantum dots (CDs) with an average size of less than 10nm were prepared by ionic liquid-assisted electrochemical exfoliation of graphite electrode, and developed as photoluminescence (PL) and electrochemiluminescence (ECL) probes for efficient detecting Ru(bpy)3 2+ in the solution based on the quenching of the PL emission of CDs and enhanced ECL of Ru(bpy)3 2+, respectively. The PL and ECL probes exhibited a detection limit of 0.72 and 0.43μM, respectively. The PL and ECL properties of CDs and Ru(bpy)3 2+ will provide a new route to study the novel materials and broaden the use of them in analyte detection. [Copyright &y& Elsevier]

Considering of the basic properties and also the two nitrogen atoms in the structure, hydrazine hydrate was employed to be an amine additive candidate, to build a Ru(bpy)/hydrazine electrochemiluminescence (ECL) system, and ECL of Ru(bpy) has been employed for the determination of hydrazine hydrate in the paper. The result demonstrated that the logarithmic ECL increasing (ΔECL = ECL − ECL) versus the logarithmic concentration of hydrazine hydrate is linear over a concentration range of 1.0 × 10 to 1.0 × 10 mol/L, on both glassy carbon and Pt electrodes in a pH 9 phosphate buffer. The hydrazine hydrate detection limit was down to 1.0 × 10 mol/L, comparatively lower than other detection methods. To check its applicability, the proposed method was applied to the determination of hydrazine hydrate added into a tap water sample with good reproducibility and stability. All these provide a possibility to develop a novel ECL detection method for hydrazine in water. [ABSTRACT FROM AUTHOR]

Abstract: In this study, a thin-film glucose electrochemiluminescence (ECL) biosensor was developed. Ru(bpy)3 2+ was doped in alcohol-free low-volume shrinkage mesoporous silica sol–gel with PEG-400 as the template, and glucose dehydrogenase (GDH) was immobilized in polymer Resydrol. NADH, which is produced by the reaction of co-enzyme NAD+ and glucose catalyzed by glucose dehydrogenase, reacts with immobilized Ru(bpy)3 2+ to generate ECL emission. Among the three types of design including two-layer, mixed and sandwich configuration, the sandwich configuration showed the best sensitivity with the calibration range of 25–2000μM and the limit of detection of 0.5μM in a flow injection analysis of glucose. The alcohol-free mesoporous sol–gel and the sandwich design made the biosensor potentially applicable in flow-injection analysis of samples. [Copyright &y& Elsevier]

Abstract: A novel and highly sensitive electrochemiluminescence (ECL) assay based on magnetic beads separation/collection process and thymine–Hg2+–thymine (T–Hg2+–T) coordination chemistry has been designed to detect Hg2+ ions in aqueous solution. In this protocol, two amine-terminated complementary DNA probes with five thymine–thymine (T–T) mismatches were introduced. One was coupled with carboxyl-modified magnetic beads and the other was labeled with tris (2, 2-bipyridine) ruthenium (II) (TBR). The couple of DNA probes, in the presence of Hg2+, can form double-stranded structure via the Hg2+-mediated coordination of T–Hg2+–T base pair. Therefore, they can be collected on the surface of electrode using a magnetic field. On the electrode, TBR labels and tripropylamine (TPA) could react to emit photons, which were detected by a custom-built ECL system. The detection limit for Hg2+ in this assay is 5nM, which is below the upper limit of Hg2+ for drinkable water mandated by United States Environmental Protection Agency (EPA), 10nM. To the best of our knowledge, this is the first example of ECL assay applying to detect Hg2+ with highly sensitivity and selectivity. [ABSTRACT FROM AUTHOR]

Efficient quenching electrochemiluminescence (ECL) of the [image omitted]/tripropylamine (TPrA) system by a novel quencher Caffeic acid (CA) has been investigated. The quenching behaviors can be observed with a 100-fold excess of CA over [image omitted]. The mechanism of quenching is believed to involve energy transfer from the excited-state [image omitted] to the electro-chemical oxidation of CA, which was formed at the electrode surface. Photoluminescence experiments coupled with bulk electrolysis support formation of the oxidation product of CA upon electrochemical oxidation. [ABSTRACT FROM AUTHOR]

An electrochemiluminescence–polymerase chain reaction (ECL–PCR) method for point mutation detection has been developed. The target is amplified using a tris (bipyridine) ruthenium (TBR)-labeled forward and a biotinylated reverse primer. The amplification products are digested with specific restriction enzyme, then captured onto streptavidin-coated paramagnetic beads, and detected by measuring the ECL signal of the TBR label. The established technique was further applied to detect a specific point mutation in H-ras oncogene in T24 cell line. The results show that the system has a low detection limit of 100 fmol and a linear range of more than 3 orders of magnitude for H-ras amplicon; the two genotypes can be reliably discriminated. In summary, the mutant specific ECL–PCR method can be used to detect a point mutation that creates or destroys a restriction site in any gene. It is useful in single nucleotide polymorphism (SNP) and mutation detection due to its safety, high sensitivity and simplicity. [Copyright &y& Elsevier]

Abstract: Phase-modulated electrochemiluminescence (ECL), induced by modulating the applied potential, is reported for thin films of the metallopolymer, [Ru(bpy)2PVP10]2+, where bpy is 2,2′-bipyridyl and PVP is Poly 4-vinyl pyridine. Using a frequency of 0.25Hz and an amplitude of 60mV, a detection limit of 5μM was obtained for oxalate which is a factor two lower than that obtained using a static DC potential. Significantly, the modulation technique shows higher sensitivity with a slope equal to 15.6intensity units mM−1 which is an order of magnitude larger than the unmodulated signal. The phase-modulated approach significantly increases the ECL signal-to-noise ratio, allows ECL measurements to be recorded under ambient light conditions and decreases the measurement time. [Copyright &y& Elsevier]