He Zhike

Chemiluminescence determination of thiourea using tris (1,10-phenanthroline)-ruthenium (II) KMnO4 system

The light emission produced by thiourea in oxidation process by permanganate in acidic solution in the presence of Ru(phen)23+ is used to determine 1.0×10−5 −1.0×10−5 mol/L thiourea. The limit of detection is 9.8×10−9 mol/L and the relative standard deviation is 1.1% for a 1.0×10−5 mol/L thiourea solution (n=10). The method was applied satisfactorily to the determination of thiourea.

Chemiluminescence determination of tetracycline and oxytetracycline in pharmaceutical preparations using Ru (bipy)3 2+-cerium (IV) system

A new chemiluminescence (CL) method for the determination of tetracycline and oxytetracycline is developed, based on the CL reaction of tetracycline and oxytetracycline with Ru (bipy)32+ and Ce (IV). In sulfuric acid medium, the CL emission is generated upon continuous oxidtion of Ru(bipy)32+ by cerium (IV). The emission intensity is greatly enhanced when tetracycline and oxytetracycline are introduced into the reaction system after acid degradation. Under the optimum conditions, the calibration curves are linear over the range of 8.0×10−8∼4.0×10−6 mol/L for tetracycline and of 2.0×10−7∼4.0×10−5 mol/L for oxytetracycline, with the detection limits are 4.2×10−8 mol/L for tetracycline and 1.5×10−7 mol/L for oxytetracycline, respectively. The proposed method was used for the determination of tetracycline and oxytetracycline in pharmaceutical formulations with good results.

Determination of some carbonyl carboxylic acids using chemiluminescent reaction of Ru(bipy)3 2+−Ce(IV)

A coupled chemiluminescence method for the determination of some carboxylic acids was developed, based on their enhancement the chemiluminescence light emission of the reaction of tirs (2,2′-bipyridine) ruthenium(II) and Ce(IV) in sulfuric acid medium. The conditions for their determination were optimized. The following detection limits were obtained: oxalic acid, 2.67×10−8 mol/L; propandioic acid, 1.20×10−6 mol/L; pyruvic acid, 1.35×10−8 mol/L; citric acid, 5.10×10−8 mol/L; barbituric acid, 2.48×10−7 mol/L. The proposed method was successfully applied to determination of oxalic acid. The coupled chemiluminescent reaction mechanism and rate equation are proposed.

Investigation of Ru （ phen ）3^2＋-Hydrazine-Ce（IV） Chemiluminescence System and Its Analytical Application

It was observed that hydrazine could enhance the chemiluminescence (CL) intensity of tris-(1,10-phenanthroline) ruthenium(II) (Ru (phen)32+)-Cerium (IV) (Ce(IV)) system, based on which, a novel CL system, Ru(phen)32+-Hydrazine-Ce(IV), was established. This CL system was investigated and employed to detect hydrazine. Under the optimum experimental conditions, the linear range and detection limit of the proposed method are 2.0×10−6–2.0×10−3 g ·L−1 and 1.8×10−6 g·L−1, respectively. For 1.5×10−5, 1.5×10−4 and 1.2×10−3 g·L−1 hydrazine, the relative standard deviation (RSD) is 2.9%, 2.2% and 3.1%, respectively (n=11). The proposed method has been used to detect the content of hydrazine in the synthetic samples with satisfactory results.

Optical Properties of Ru（bipy）2 （dppx）^2＋ in Different Environments

The emission spectra of Ru(bipy)2 (dppx)2+ in different environments has been studied. It was found that the solvent polarity and the ability of donating and transferring proton are the important factors in predicting luminescence intensity in different systems. The increasing content of water in the organic solutions of Ru(bipy)2 (dppx)2+ leads to decrease in emission intensity that follows the Perrin sphere of quenching model. The effect of base content of DNA on the fluorescence spectra of Ru (bipy)2 (dppx)2+ has also been studied.

Sensitive determination of DNA by RLS enhancement of metal ions

The interactions between metal ions and DNA have been studied by the resonance light scattering (RLS) spectra. In the acidic condition, the RLS signals of metal ions, especially the transition metal ions in group IB and IIB, were increased by DNA. And it is found that the enhancement of RLS signals is linear to the concentration of DNA, so the RLS method for DNA determination was proposed in the presence of Cu2+. On the optimum conditions, the linear range and the detect limit of ctDNA is 4×10−8–4×10−6 g· mL−1 and 1. 13×10−8 g·mL−1, respectively. The proposed method is successfully applied to determine the extracted plasmid DNA ofBacillus subtilis DB104.

HPLC determination of ascorbic acid using luminol-Cu (II) chemiluminescence-application to the analysis of juice beverage.

The chemiluminescence (CL) of luminol-Cu (II) was applied to HPLC determination of ascorbic acid, which was separated by a C18 reverse-phase column with a mobile phase of 0.25 mol/L HAc. The eluted ascorbic acid was mixed with 0.3 mmol/L luminol and 0.05 mol/L CuSO4. The light emission from the reaction of Cu(II) oxidized ascorbic acid and luminol was detected by a modified luminometer. The detection limit was 3.6×10−6 mol/L for ascorbic acid at aS/N ratio of 3, and the linear calibration range was 2×10−4–2×10−3 mol/L. The relative standard deviation for 5 replicate injections of 1×10−3 mol/L ascorbic acid was calculated as 4.3%. The method was successfully applied to determination of ascorbic acid in juice beverage.

Studies on the interaction of DNA and Ru (1,10-phenanthroline)2− (dipyrido[3,2−a:2′,3′−c]phenazine)2+

The interaction of Ru(phen)2(dppz)2+(phen=1,10-phenanthroline,dppz=dipyrido[3,2−1:2′,3′−c]phenazine) and the calfthymus DNA were studied with fluorescence and ultraviolet visible absorption spectroscopy. The ultraviolet visible absorption spectrum of Ru(phen)2(dppz)2+ calfthymus DNA, and their interaction demonstrated that Ru(phen)2(dppz)2+ intercalated into the double helix of DNA via the ligand dppz. Fe(CN)64− and NaCl can not quench the fluorescence of Ru(phen)2(dppz)2+-DNA, which was in agreement with the intercalation mode.