A new electrochemiluminescent detection system equipped with an electrically heated carbon paste electrode for CE

An electrochemiluminescent (ECL) detection system in CE with an electrically heated carbon paste electrode (CPE) was developed. This CPE could be heated by a 100 kHz alternating current (ac) generated from a function generator, and the temperature of the electrode (Te) could be controlled. To evaluate the feasibility and reliability of this system, the electrochemically generated Ru(bpy)(3) (3+)-based ECL reaction was used for detection of triethylamine (TEA) and tri-n-propylamine (TPrA). Ru(bpy)(3) (2+) was added into the separation buffer solution with precolumn mode. Effects of several important factors were investigated to acquire the optimum conditions. Under the optimum conditions, the heated electrode has been shown to provide advantages by the measurement of ECL intensity in CE at elevated Te. Compared with the conventional electrode at the room temperature, using heated CPE could improve peak shape and gain good reproducibility with lower detection limits and wider linearity ranges. Compared with the room temperature, the linear ranges and detection limits (S/N = 3) for TEA and TPrA were improved about one magnitude when the Te was 39 degrees C. In contrast, the RSD was lower than for the electrode at room temperature.     

High electrochemiluminescence intensity of the Ru(bpy)3 2+/oxalate system on a platinum net electrode

A new method for enhancing the electrochemiluminescence (ECL) intensity of the Ru(bpy)₃ ²⁺/ oxalate system is presented. When a platinum net was used as a working electrode and a platinum foil as an auxiliary electrode, the ECL intensity of the system was enhanced greatly. In addition, a cathodic peak appeared at 0.18 V (vs. SCE) on a platinum net electrode, and ECL of the system was observed at 0.18 V.     

Kinetic study of paracetamol on prolidase activity in erythrocytes by capillary electrophoresis with Ru(bpy)(3) (2+) electrochemiluminescence detection

We explored the CE with (bpy) (2+) (3) electrochemiluminescence detection for the kinetic study of drug-enzyme interaction. Effects of four nonsteroidal anti-inflammatory drugs including aspirin, paracetamol, sodium salicylate and phenacetin on prolidase (PLD) activity in erythrocytes were investigated. Aspirin enhanced PLD activity whereas the other three had inhibiting effects. This may reveal their different effects on the collagen biosynthesis and catabolism that influence tumor invasiveness. Kinetic study of paracetamol on PLD showed that the value of Michaelis constant K(m) for PLD was 1.23 mM. The mechanism of PLD inhibition by paracetamol is noncompetitive inhibition, and the inhibitor constant K(i) value obtained in our research was 9.73 x 10(3) microg/L.     

"Proof-of-principle" concept for ultrasensitive detection of cytokines based on the electrically heated carbon paste electrode

The proof-of-principle of the integration of electrically heated carbon paste electrode with immunoassay as a potential alternative for ultrasensitive detection of cytokines was demonstrated.     

A new electrochemiluminescent detection system equipped with an electrically controlled heating cylindrical microelectrode

A new electrochemiluminescent (ECL) detection system equipped with an electrically controlled heating cylindrical microelectrode (HME) was developed in this paper. The cylindrical microelectrode made of platinum wire (25 μm in diameter, 6 mm in long) was used as the working electrode of the ECL detection system, the temperature of the electrode could be controlled electrically. The Ru(bpy)₃²⁺-ECL and Ru(bpy)₃²⁺-C₂O₄²⁻-ECL systems were used to evaluate this ECL detection system. The detection limit for oxalate was found to be 3.0 × 10⁻⁴ mol/L when T_e (temperature of the HME) was 22 °C, and found to be 3.0 × 10⁻⁶ mol/L at 80 °C, which indicates that the detection limit can be improved greatly at higher T_e, based on which, it is possible to establish a more sensitive method for measurement of ECL by using a heated microelectrode.     

Ru(bpy)_3~(2+)-C_2O_4~(2-)-PtE体系的两条电致化学发光通道

运用电位分辨电致化学发光 (PRECL)手段发现Ru(bpy) 2 + 3 C2 O2 -4 PtE体系在预氧化的多晶铂电极上存在两个发光通道 ,这两个通道分别位于 1.2 2V和 1.40V处 .对影响两发光通道的条件进行了研究 ,比较了几种经过不同预处理方式 (直接抛光、阳极极化和阴极极化的电极以及S吸附电极 )以及体系中不同C2 O2 -4 浓度 ,pH ,溶解氧和溶解二氧化碳对两PRECL峰形、峰强度的影响 .提出第二个ECL发光峰的机制为C2 O2 -4 直接电极氧化产物CO2 -·(或C2 O4 -·)的催化发光 .     

Nanoscale-enhanced Ru(bpy)3(2+) electrochemiluminescence labels and related aptamer-based biosensing system

A unique multilabeling at a single-site protocol of the Ru(bpy)(3)(2+) electrochemiluminescence (ECL) system is proposed. Nanoparticles (NPs) were used as assembly substrates to enrich ECL co-reactants of Ru(bpy)(3)(2+) to construct nanoscale-enhanced ECL labels. Two different kinds of NP substrates [including semiconductor NPs (CdTe) and noble metal NPs (gold)] capped with 2-(dimethylamino)ethanethiol (DMAET) [a tertiary amine derivative which is believed to be one of the most efficient of co-reactants of the Ru(bpy)(3)(2+) system] were synthesized through a simple one-pot synthesis method in aqueous media. Although both CdTe and gold NPs realized the enrichment of ECL co-reactants, they presented entirely different ECL performances as nanoscale ECL co-reactants of Ru(bpy)(3)(2+). The different effects of these two NPs on the ECL of Ru(bpy)(3)(2+) were studied. DMAET-capped CdTe NPs showed enormous signal amplification of Ru(bpy)(3)(2+) ECL, whereas DMAET-capped gold NPs showed a slight quenching effect of the ECL signal. DMAET-capped CdTe NPs can be considered to be excellent nanoscale ECL labels of the Ru(bpy)(3)(2+) system, as even a NP solution sample of 10(-18) M was still detectable after an electrostatic self-assembly concentration process. DMAET-capped CdTe NPs were further applied in the construction of aptamer-based biosensing system for proteins and encouraging results were obtained.     

Ru(bpy)^2^+~3-C2O^2^-~4-PtE体系的两条电致化学发光通道

运用电位分辨电致化学发光(PRECL)手段发现Ru(bpy)^2^+~3-C2O^2^-~4-PtE体系在预氧化的多晶铂电极上存在两个发光通道,这两个通道分别位于1.22V和1.44V处,对影响两发光通道的条件进行了研究,比较了几种经过不同预处理方式(直接抛光、阳极极化和阴极极化的电极以及S吸附电极)以及体系中不同C2O^2^-~4浓度,pH,溶解氧和溶解二氧化碳对两PRECL峰形、峰强度的影响。提出第二个ECL发光峰的机制为C2O^2^-~4直接电极氧化产物CO^-^.~2(或C2O^-^.~4)的催化发光。     

The excited-state absorption of Ru(bpy)2+3 reexamined

The excited-state absorption of Ru (bpy)₃²⁺ ( RBY ) in the range 240 to 2200 nm is reported, extending the range and improving the resolution of previous measurements. The excitation power dependence of the excited-state populations are quantified and absorption measurements made in H₂O and D₂O solutions at 300 K and in poly (vinyl-alcohol) (PVA) films at 20 K. No evidence is found for an intervalence charge-transfer type transition in the near IR, but the Ψ→ χ ligand excitation transition is clearly seen near 11000 and 9000 cm⁻¹ in solution and in PVA respectively. The visible and UV excited-state spectra are similar in the two environments and differences are attributed to the effects of photoselection in PVA. The Ψ→ χ transition shows a marked shift in passing from a rigid to a fluid medium, indicating the possibility of a change in ligand geometry.     

Chemiluminescence of Ru(bpy)3 2+* in the reaction of electron transfer from Ph3CNa to Ru(bpy)3 3+ in a solution

Conditions for the generation of the Ru(bpy)₃ ³⁺ complex in organic solvents (Me₃CN or MeNO₂) in the presence of small amounts of H₂SO₄ were found. Chemiluminescence was observed in the reaction of Ru(bpy)₃ ³⁺ with Ph₃Na in a THF-MeCN mixture. The chemiluminescence emitter was identified as Ru(bpy)₃ ^2+*. This emitter forms in the excited state in the elementary reaction of electron transfer from the Ph₃C⁻ anion to Ru(bpy)₃ ³⁺. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 2, pp. 292–294, February, 1999.     

Chemiluminescence of Ru(bpy)3Cl2 complex in heterogeneous systems

Conclusions The excitation of the Ru(bpy)₃Cl₂ complex, deposited on a solid support, was observed in a chemiluminescent reaction involving hydroperoxides.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 10, pp. 2365–2368, October, 1981.     

Redox-switchable direction of photoinduced electron transfer in an Ru(bpy)3(2+)-viologen dyad

Quenching of the 3MLCT excited state of [Ru(bpy)3]2+ (bpy=bipyridine) by the reduction products (MV*+ and MV0) of methyl viologen (MV2+) was studied by a combination of electrochemistry with laser flash photolysis or femtosecond pump-probe spectroscopy. Both for the bimolecular reactions and for the reactions in an Ru(bpy)3(2+)-MVn+ dyad, quenching by MV*+ and MV0 is reductive and gives the reduced ruthenium complex [Ru(bpy)3]+, in contrast to the oxidative quenching by MV2+. Rate constants of quenching (kq), and thermal charge recombination (krec) and cage escape yields (phi(ce)) were determined for the bimolecular reactions, and rates of forward (kf) and backward (kb) electron transfer in the dyad were measured for quenching by MV2+, MV*+, and MV0. The reactions in the dyad are very rapid, with values up to kf = 1.3 x 10(12) s(-1) for *Ru(bpy)3(2+)-MV*+. In addition, a long-lived (tau = 15 ps) vibrationally excited state of MV*+ with a characteristically structured absorption spectrum was detected; this was generated by direct excitation of the MV*+ moiety both at 460 and 600 nm. The results show that the direction of photoinduced electron transfer in a Ru(bpy)3-MV molecule can be switched by an externally applied bias.     

联吡啶和邻菲咯啉混配的钌配合物的核磁共振氢谱分析

合成了Ru(bpy)2(phen)(PF6)2 和Ru(bpy)(phen)2(PF6)2 (bpy和phen分别为2,2′-联吡啶和1,10 -邻菲咯啉)两种电化学发光物质,以 1HNMR谱研究这两种配合物的立体结构,利用 1H - 1HCOSY(同核相关谱)核磁共振技术详细分析并归属了它们的氢谱峰。     

Enhanced anodic Ru(bpy)3(2+) electrogenerated chemiluminescence by polyphenols

Anodic Ru(bpy)₃²⁺ electrogenerated chemiluminescence (ECL) can be enhanced by polyphenols in alkaline solution. Spin trapping-electron spin resonance (ESR) experiments verified that reactive oxygen species (ROS) were generated during the electrolysis of Ru(bpy)₃²⁺ in alkaline solution, and oxidation of quercetin enhanced Ru(bpy)₃²⁺ ECL at anodic potential by producing additional ROS. This ECL enhancement can be used to analyze real sample and evaluate antioxidant activity of polyphenols.     

联吡啶钌电化学发光研究进展

联吡啶钌电化学发光在免疫分析、核酸分析、共反应物分析和适配子传感器等方面具有广泛的应用前景,成为在诸多电化学发光体系如9,10-二苯基蒽、光泽精、联吡啶钌、过氧化草酸酯、鲁米诺、石墨烯和量子点等之中近年来国际上研究最多的电化学发光体系之一.本综述对已发表的绝大多数联吡啶钌电化学发光成果加以归纳总结,简要介绍联吡啶钌电化学发光的概况,并尝试展望其今后的研究趋势.     

钌联吡啶单配体双取代基效应

对钌联吡啶配合物及其单配体的4,4′ 双取代衍生物, 用量子化学密度泛函(DFT)方法在B3LYP/LanL2DZ水平上进行计算.探讨一些强的推电子基团(如－OCH3)和强的拉电子基团(如－NO2)的取代基效应对配合物的电子结构与相关性质,如配位键长、光谱性质等的影响规律,为该类配合物的合成,光、电、催化和生化作用机理分析提供理论参考.     

Cathodic electrochemiluminescence and reversible electrochemistry of [Ru(bpy)3]2+/1+ in aqueous solutions on tricresyl phosphate-based carbon paste electrode with extremely high hydrogen evolution potential

Many cathodic electrochemiluminescence (ECL) systems require very negative potentials; it is difficult to achieve stable cathodic ECL in aqueous solutions because of hydrogen evolution and instability of intermediates. In this study, tricresyl phosphate-based carbon paste electrode (CPE) was used to achieve cathodic ECL. It exhibits no obvious hydrogen evolution even at a potential up to ?1.6 V and dramatically stabilizes electrogenerated [Ru(bpy)₃]⁺. Therefore, a reversible wave of [Ru(bpy)₃]^2+/1+ in aqueous solutions at carbon electrode has been observed for the first time, and cathodic ECL of [Ru(bpy)₃]²⁺/S₂O ₈ ^2? has been achieved. Under the optimum conditions, the plots of the ECL versus the concentration of S₂O ₈ ^2? are linear in the range of 10^?6 to 10^?2 M with the detection limit of 3.98?×?10^?7 M. Common anions have no effect on the ECL intensity of the [Ru(bpy)₃]²⁺/S₂O ₈ ^2? system. Since CPEs have been widely used, CPEs with high hydrogen evolution potential are versatile platforms for electrochemical study and cathodic ECL study.     

Modulated potential electrogenerated chemiluminescence of luminol and Ru(bpy) 3 2+

Chemiluminescence emission intensity is modulated by modulating the potential of a working electrode which is used to generate a key species in the electrogenerated Chemiluminescence (ECL) reaction. The emission is monitored synchronously using a lock-in amplifier. The reactions used in the characterization are luminol with hydrogen peroxide and tris(2,2-bipyridyl)ruthenium (II) (or Ru(bpy) ₃ ²⁺ ) with oxalate. Modulation widths of ± 50 mV yield maximum signals for luminol when centered at 0.45 V (vs Ag/AgCl) and for Ru(bpy) ₃ ²⁺ when centered at 1.05 V. The resulting signal decreases with increasing modulation frequency and shows that luminol/H₂O₂ is a faster ECL system than Ru(bpy) ₃ ²⁺ /oxalate. Working curves for luminol and for oxalate have essentially the same linear range and slope with the modulated potential approach as with a DC electrode potential. This approach provides capability for differentiating the analytical signal from constant background emission or stray light.     

The enhanced electrogenerated chemiluminescence of Ru(bpy)3(2+) by glutathione on a glassy carbon electrode modified with some porphine compounds

It has been found that the electrochemical activity of glutathione was increased greatly at the glassy carbon electrodes modified with 5,10,15,20-tetraphenylporphine ruthenium(II) carbenyl (RuTPP), meso-tetraphenylporphine copper(II) complex (CuTTP) and hemin. It has been also found that glutathione would enhance the electrogenerated chemiluminescence (ECL) of Ru(bpy)3(2+) at a hemin glassy carbon electrode; the enhanced ECL intensity was linear with the concentration of glutathione in the range of 1 x 10(-7)-1 x 10(-4) mol l-1, based on which method for determination of glutathione has been developed. The detection limit of glutathione was 2 x 10(-8) mol l-1, and the relative standard deviation for 1 x 10(-6) mol l-1 glutathione was 2.7%. The mechanism for this ECL system has been proposed.