THE STUDY OF LUMINOL-H_2O_2-IO_4^--S^(2-)CHEMILUMINESCENCE SYSTEM AND ITS APPLICATION

This paper reports a new chemiluminescence system i.e.luminol- H_2O_2-IO_4^- catalyzed by sulphide ion(S^(2-)).Based on this catalysis,a new chemiluminescence(CL)method for the determination of trace S^(2-)is pro- posed.The detection limit is 0.2μg/LS^(2-),the linear dynamic range is 5μg to 100βμg/L S^(2-)and the variation coefficient at an sulphide concentration of 100μg/L S^(2-)is 4.5%(n=10).The method has been satisfactory applied to the determination of trace sulphide ion in water.

A Capillary Electrophoresis Detection Scheme for Water-soluble Vitamins Based on Luminol-BrO^- Chemiluminescence System

A novel chemiluminescence detection scheme has been developed for detecting water-soluble vitamins following capillary electrophoresis (CE) separation. This detection was based on the inhibitory effect of vitamins on the CL reaction between luminol and BrO- in basic aqueous solution. Detection of vitamins was accomplished with a boratebased background electrolyte at pH 9.2. The luminol was used as a component of the separation carrier electrolyte.

Determination of Ciprofloxacin by Flow Injection Analysis Based on Chemiluminescence System

A novel flow injection chemiluminescence （CL） method for the determination of ciprofloxacin （CPLX） was reported. The proposed method is based on luminescence produced by KMnO4-Na2S2O4-Tb^3＋-CPLX chemiluminescence （CL） system. The effects of some critical experimental conditions were discussed and the optimization of working conditions was investigated. The linear dynamic range is 3.00 × 10^-8 - 9.00 × 10^-7 mol ·L-1 and the detection limit for CPLX is 4.40 × 10^-9 mol·L^-1. This method was applied to the determination of CPLX in tablet, urine, and serum samples and the recoveries of real sample analyses were in the range from 110 ± 4 to 104 ± 4.

Spectral analysis in ultraweak emissions of chemi-and electrochemiluminescence systems

Investigation of ultraweak emissions in the processes of chemiluminescence, CL, and electrochemiluminesce, ECL, requires special techniques of their recording and spectral analysis. From among the hitherto proposed methods of detection of the emission spectra of these processes, that of the cut-off filter was most sensitive. The usefulness of this method in interpretation of the CL and ECL systems of the quantum yields in the range 1×10^-9-1×10^-11 containing ions and complexes of Eu（Ⅲ）, Tb（Ⅲ） and Dy0ID was shown. Exceptional character of the emission bands of lanthanide ions, being a result of the f-f electron transitions and in particular their low FWHM, permitted the appli- cation of the cut-off filter method to their analysis. The results obtained for CL and ECL on the basis of analysis of ultraweak emission proved to be successful in analytical applications. The systems containing Eu（Ⅲ） ions hydrated or complexed with organic ligands enabled inferring changes in the coordination sphere of the ions.

Highly sensitive trivalent copper chelate-luminol chemiluminescence system for capillary electrophoresis chiral separation and determination of ofloxacin enantiomers in urine samples

A simple,fast and sensitive capillary electrophoresis（CE） strategy combined with chemiluminescence（CL） detection for analysis of ofloxacin（OF） enantiomers was established in the present work.Sulfonated p-cyclodextrin（β-CD） was used as the chiral additive being added into the running buffer of luminol-diperiodatocuprate（Ⅲ）（K[Cu（HIO6）2],DPC） chemiluminescence system.Under the optimum conditions,the proposed method was successfully applied to separation and analysis of OF enantiomers with the detection limits（S/N=3） of 8.0 nM and 7.0 nM for levofloxacin and dextrofloxacin,respectively.The linear ranges were both 0.010-100 μM.The method was utilized for analyzing OF in urine;the results obtained were satisfactory and recoveries were 89.5-110.8%,which demonstrated the reliability of this method.This approach can also be further extended to analyze different commercial OF medicines.

Assay of Cysteine in Human Serum with Quinine-Ce^(4+) Chemiluminescence System

A sensitive and selective chemiluminescence (CL) method was developed for the determination of cysteine. This method is based on that the weak CL of cysteine oxidized with cerium (IV) can be greatly enhanced by quinine, and the total cysteine in human serum can be detected through simply diluting with water, showing a simpler analytical characteristic.

Luminol-K_3Fe(CN)_6 chemiluminescence system for the determination of glipizide

A rapid and sensitive flow-injection chemiluminescence（CL） method for the determination of glipizide was developed on the basis of finding that glipizide can enhance the CL intensity of the luminol-K3Fe（CN）6 system.In optimum condition,the increased CL intensity was directly proportional to the concentration of glipizide in the range from 4.0×108 g/mL to 1.0×106 g/mL and the detection limit was 1.0×108 g/mL glipizide.The relative standard deviation（RSD） of the developed method was 2.1% with 11 repeated measurements of 1.0×107 g/mL glipizide.The developed method has been successfully applied to the analysis of glipizide in its pharmaceutical preparations.

An optimized, sensitive and stable reduced graphene oxide–gold nanoparticle-luminol-H_2O_2 chemiluminescence system and its potential analytical application

The chemiluminescence （CL） performance of luminol is improved using reduced graphene oxide/gold nanoparticle （rGO-AuNP） nano-composites as catalyst. To prepare this catalyst, we propose a linker free, one-step method to in- situ synthesize rGO-AuNP nano-composites. Various measurements are utilized to characterize the resulting rGO-AuNP samples, and it is revealed that rGO could improve the stability and conductivity. Furthermore, we investigate the CL signals of luminal catalyzed by rGO-AuNP. Afterwards, the size effect of particle and the assisted enhancement effect of rGO are studied and discussed in detail. Based on the discussion, an optimal, sensitive and stable rGO-AuNP-luminon- H202 CL system is proposed. Finally, we utilize the system as a sensor to detect hydrogen peroxide and organic compounds containing amino, hydroxyl, or thiol groups. The CL system might provide a more attractive platform for various analytical devices with CL detection in the field of biosensors, bioassays, and immunosensors.

Study on Quenching Effect of Holmium (Ⅲ) Ion in Chemiluminescence System of Luminol H_2O_2-Cr(Ⅲ) by Flow Injection Technique

A new chemiluminescence (CL) analytical method for determination of rare earth Ho(Ⅲ) ion is reported. It is based on the quenching effect of Ho(Ⅲ) ion on CL intensity of Luminol H 2O 2 Cr(Ⅲ) system. The detection limit is 3×10 -8 mol/L, the linear range is from 1×10 -7 to 1×10 -4 mol/L; the relative standard deviation is less than 3% (for 2×10 -7 mol/L Ho, n=11). The method was applied to determination of Ho(Ⅲ) in pure samples with satisfactory results.

Determination of Biotin in Pharmaceutical Formulations by Potassium Permanganate-luminol-CdTe Nanoparticles Chemiluminescence System

A sensitive flow-injection chemiluminescence method was developed for the determination of biotin in the pharmaceutical formulations.The affinity between avidin and biotin was used to adsorb biotin on the polystyrene,with subsequent quantification of biotin based on its ability to enhance the chemiluminescence（CL） signal generated by the redox reaction of potassium permanganate-luminol-CdTe nanoparticles CL system.The investigations prove that apart from 3-aminophthalate,the CdTe quantum dots（QDs） play both catalytic and emitter roles.Under optimum conditions,the linear range for the determination of biotin was 0.01―25 ng/mL with a detection limit of 7.3×10-3 ng/mL（S/N=3）.The relative standard deviation of 5 ng/L biotin was 2.06%（n=7）.The proposed method was used to determine the biotin concentration in the pharmaceutical formulations and the recovery was between 96.4% and 104%.The proposed method is simple,convenient,rapid and sensitive.

Luminol-potassium permanganate chemiluminescence system for the determination of three anthracycline antibiotics

Objective To establish a flow-injection chemiluminescence method for the determination of doxorubicin,epirubicin and mitoxantrone and study its reaction mechanism.Methods In alkaline medium,chemiluminescence of luminol-potassium permanganate system could be inhibited obviously by anthracycline antibiotics.Combined with flow-injection technique,a new chemiluminescence method for determining the anthracycline antibiotics was set up.The chemiluminescence mechanism of the luminol-potassium permanganate system was also discussed.Results Under optimal conditions,the good linear ranges of doxorubicin,epirubicin and mitoxantrone were 5.0×10-9-1.0×10-6g/mL,1.0×10-9-1.0×10-5g/mL and 3×10-9-1.0×10-6g/mL,respectively.The detection limits of doxorubicin,epirubicin and mitoxantrone were 3.0×10-9g/mL,5.0×10-8g/mL and 2.0×10-9g/mL,respectively.During eleven repeated inter-day and intra-day precision tests of 1.0×10-6g/mL samples,the relative standard deviations corresponded to reference values of 3.0%,2.8% and 2.1%.Conclusion The developed method is sensitive,accurate,rapid and of low cost.It can be applied to determine doxorubicin hydrochloride,epirubicin hydrochloride and mitoxantrone hydrochloride in injection preparations.

A Novel Flow Injection Chemiluminescence System for the Determination of Reserpine

A novel flow injection cheminescence (FICL) system for the determination of reserpine is presented in this paper. It is based on the CL reaction of reserpine, IO - 4 and H 2O 2 in H 2SO 4 medium. The CL intensity was correlated with concentration of reserpine in the range of 1.0×10 -6～1.0×10 -4 g/mL with a detection limit of 1.35×10 -7 g/ mL. The relative standard deviation is 2.63% for 11 measurements of 2×10 -5 g/mL reserpine standard solution. The method has been applied to the determination of reserpine in pharmaceutical preparations and the results are in good agreement with that of the standard method.

Flow injection chemiluminescence determination of meloxicam using potassium permanganate and formaldehyde system

A simple, rapid and sensitive flow injection chemiluminescence （FI-CL） method has been developed for the determination of meloxicam. The method is based on the CL-emitting reaction between meloxicam and potassium permanganate in a hydrochloric acid medium, enhanced by formaldehyde （HCHO）. Under optimum conditions, calibration curve over the range of 1.0-20.0μg/mL was obtained. The proposed method was successfully applied to the determination of meloxicam in capsules with no evi- dence of interference from common excipients. The detection limit of this method was 25.6 ng/mL. The relative standard deviation was 2.1% for 10.0 μg/mL meloxicam. The sample throughput was found to be 120 samples/h.

Chemiluminescence Determination of Molybdenum by on-Line Reduction with a Flow Injection System

The chemiluminescence (CL) reaction between lucigenin (Lu) and molybdenum (III) produced by a Jones reductor was investigated using a flow injection system. On the basis of this, a novel method for the determination of trace amount of molybdenum has been established. The emission intensity was linear with molybdenum concentration in the range of 0.1-1000 ng/mL; the detection limit was 0.02 ng/mL molybdenum; the relative standard deviation was less than 2% for the determination of 0.1 ng/mL molybdenum (n=11). The method has been applied successfully to the analysis of trace molybdenum in water and steel samples.

Flow-injection chemiluminescence determination of tryptophan using galangin-potassium permanganate-polyphosphoric acid system

A high sensitive flow-injection chemiluminescence （FI-CL） method for the determination of tryptophan has been developed. The method is based on the chemiluminescence reaction of galangin-potassium permanganate-tryptophan in polyphosphoric acid （PPA） media. Under the optimized conditions, tryptophan was determined in the range 0.05-10 μg/mL with the detection limit （3tr） of 5.0 × 10^-3 μg/mL. The relative standard deviation （RSD） was 1.0% for 11 replicate determinations of 1.0 μg/mL tryptophan. Three synthetic samples were determined selectively with recoveries in the range from 99.6% to 102.0% in the presence of other amino acids.

Chemiluminescence determination of melamine with Luminol-K_3Fe(CN)_6 system

A sensitive chemiluminescence（CL） method was developed for determining melamine in urine and plasma samples based on the fact that melamine can remarkably enhance the chemiluminescence of Luminol-K3 Fe（CN）6 system in alkaline medium. The determination conditions were optimized. Under optimum conditions, the chemiluminescence intensity had a good linear relationship with melamine in the range of 9.0 × 10^-9 - 7.0 × 10^-6 g/mL with a correlation coefficient of 0. 9992. The detection limits （3o） were 3.54 ng/mL for urine sample and 6.58 ng/mL for plasma sample. The average recoveries of melamine were 102.6% for urine sample and 95.1% for plasma sample. Melamine in samples was extracted with liquid-liquid extraction procedures and the assay results coincided very well with that determined with flow injection chemiluminescence method. The method provides a reproducible and stable approach for sensitive detection and quantification of melamine in urine and plasma samples.

Flow injection chemiluminescence determination of loxoprofen and naproxen with the acidic permanganate-sulfite system

A novel flow injection chemiluminescence（CL）method for the determination of loxoprofen and naproxen was proposed based on the CL system of KMnO4 and Na2SO3 in acid media.The CL intensity of KMnO4-Na2SO3 was greatly enhanced in the presence of loxoprofen and naproxen.The mechanism of the CL reaction was studied by the kinetic process and UV-vis absorption and the conditions were optimized.Under optimized conditions,the CL intensity was linear with loxoprofen and naproxen concentration in the range of 7.0×10^-8-1.0×10^-5g/mL and 2.0×10^-7-4.0×10^-6g/mL with the detection limit of 2.0×10-8g/mL and 3.0×10-8g/mL（S/N=3）,respectively.The relative standard deviations were 2.39% and 1.37% for 5.0×10^-7g/mL naproxen and 5.0×10^-7g/mL loxoprofen（n=10）,respectively.The proposed method was satisfactorily applied to the determination of loxoprofen and naproxen in pharmaceutical preparations.

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, hased on the CL reaction of tetracycline and oxytetracycline with Ru(bipy)_3~2+ and Ce(IV). In sulfuric acid medium, the CL emission is generated upon continuous oxidation of Ru(bipy)_3~2+ 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 X 10^-8^-4. 0 X 10^-6 mol/L for tetracycline and of 2. 0 X 10^-7~4. 0 X 10^-5 mol/L for oxytetracycline, with the detection limits are 4. 2 X 10^-8 mol/L for tetracycline and 1. 5 X 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 trace silver in waste water by 9,10-dimethylacridinium fluorosulfonate-K_2S_2O_8 chemiluminescence system

A new highly sensitive method for determination of trace silver in waste water with 9,10- dimethylacridinium fluorosulfonate (DAFA)-K_2S_2O_3, system was suggested. In the basic aqueous so- lution, trace of silver (I) showed strongly catalytic effect on the chemiluminescence system with the pre- sence of 2,2'-bipyridine. The range of the linear relationship between light intensity and concen- tration of silver (I) is 1.0×10^(-3)mol / L to 6.0×10^(-6) mol / L. The detection limit is 8.0×10^(-9)mol / L, and the RSD for 5.0×10^(-8) mol / LAg (I) is 6.5％ (n=13). In the existence of potassium fluoride, the selectivity is higher. Combining the treatment with nitric acid, the method is applied to determine some environmental waste water and the results are similar to atomic absorption spectroscopy.

Carbon dots-peroxyoxalate micelle as a highly luminous chemiluminescence system under physiological conditions

Chemiluminescence(CL) has been widely used for bioanalysis owing to its high sensitivity, low background and simplicity. However, most of the CL systems need acidic/alkaline conditions or organic solvent to enhance their luminescent efficiency, and the non-physiological conditions can usually lead to the misfunction of biomolecules during biosensing. Herein, we report a highly luminous CL system under physiological conditions based on carbon dots-bis(2-carbopentyloxy-3,5,6-trichlorophenyl) oxalate(CDsCPPO) micelles, and further used it in biosensing application. In the CL system, the amphiphilic surfactant packed CPPO and hydrophobic CDs together to form CDs-CPPO micelles. Such micelles solution not only isolated the CPPO from water to prevent its hydrolysis but also made the close proximity between CPPO and CDs, thus significantly enhancing the CDs quantum yield. The CL quantum yield was calculated to be 5.26 × 10^(-4) einsteins/mol, about 200-fold higher than that of the most commonly used luminol CL system. The oxidases(e.g., glucose oxidase) were tested to be susceptible to the organic solvent and non-physiological p H. Hence, the CL system was used for the detection of oxidase substrates(exemplified by glucose) in serum samples, and the limit of detection was as low as 8.4 nmol/L. The highly luminous CL system that can work under physiological conditions is promising for biosensing applications.