Huichun Zhao

Flow-injection analysis of two fluoquinolones by the sensitizing effect of terbium(III) on chemiluminescence of the potassium permanganate-sodium sulfite system

A simple, rapid and sensitive method for the determination of two fluoquinolones (FQs), enoxacin (ENX) and ofloxacin (OFLX) is described by using flow injection analysis with potassium permanganate-sodium sulfite chemiluminescence detection. The calibration graphs for ENX and OFLX are linear in the range of 8.0x10(-10)-1.0x10(-5) and 1.0x10(-9)-1.0x10(-6) mol l(-1), respectively. The 3sigma limits of detection are 2.4x10(-10) mol l(-1) for ENX and 5.6x10(-10) mol l(-1) for OFLX. The method is applied satisfactorily to the determination of the two FQs in dosage form and urine sample. The possible mechanism is also proposed.

Capillary electrophoresis-chemiluminescence determination of norfloxacin and prulifloxacin.

A capillary electrophoresis (CE)-chemiluminescence (CL) method for determining norfloxacin (NFLX) and prulifloxacin (PFLX) was developed based on the enhanced CL intensity of the cerium(IV)-sulfite-fluoroquinolone (FQ) reaction sensitized by terbium(III). The separation was conducted in buffer composed of 20 mM sodium citrate, 4 mM citric acid and 10 mM sodium sulfite at pH 6.1. The CL reagent solution consisted of 2 mM cerium(IV), 4 mM terbium(III) and 1.1 mM hydrochloric acid. NFLX and PFLX were baseline separated within 11 min with detection limits (S/N=3) of 0.057 and 0.084 microg mL(-1), respectively. The maximum intra- and inter-day relative standard deviations (R.S.D.s) of migration time of the analytes were less than 4.0% and 4.2%, respectively. The proposed method was applied to detect NFLX and PFLX in fortified urine sample and the results were comparable to high-performance liquid chromatography (HPLC)-UV method. Moreover, the high selectivity of the CL detection and the high-separation efficiency of CE render the method the potential of quick analyzing fluoroquinolones in real complex matrix.

A study on terbium sensitized chemiluminescence of ciprofloxacin and its application

Abstract A novel rapid flow injection method with chemiluminescence (CL) detection was established for the determination of ciprofloxacin (CPLX), which is an antibiotic commonly used. The method is based on CL of Ce(IV)–SO 3 2− sensitized by Tb 3+ –CPLX, and showed the intensive bands characteristic of Tb 3+ ( 5 D 4 → 7 F 5 ). The optimum conditions for CL emission were investigated. The linear relationship between the relative CL intensity and the concentration of CPLX is in the range of 9.0×10 −9 –1.0×10 −6 mol/l with a detection limit of 3.1×10 −10 mol/l. The relative standard deviation is 2.8% ( n =11) for a level of 5.0×10 −8 mol/l. The method was applied to the analysis of CPLX in human serum and urine samples with satisfactory results. The possible mechanism for this sensitized CL reaction is also discussed.

Determination of Ciprofloxacin by Flow Injection Analysis Based on Chemiluminescence System

Abstract A novel flow injection chemiluminescence (CL) method for the determination of ciprofloxacin (CPLX) was reported. The proposed method is based on luminescence produced by KMnO 4 -Na 2 S 2 O 4 -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.

Flow-injection chemiluminescence study of Ce(IV)–Na2SO3–Tb(III)–fluoquinolone antibiotic system with DNA

A novel flow injection chemiluminescence (CL) system is developed to determine DNA. According to the fact that DNA linearly quenches the CL intensity of Ce(IV)-Na(2)SO(3)-Tb(III)-fluoquinolone antibiotic (FLUQ) system, DNA concentration is determined. The calibration graphs are linear in the range of 0.04-10 microg/ml (for both natural and denatured DNA), and the 3sigma limits of detection are 7.8 ng/ml (natural DNA) and 9.5 ng/ml (denatured DNA). According to fluorescence spectrum and CL spectrum, and through studying the reaction of Ce(IV)-Na(2)SO(3)-Tb(III)-FLUQ with nucleotides and bases, we conclude that DNA counteracts the energy transfer from FLUQ to Tb(III), and this function is related to both bases and phosphate groups in DNA.

A STUDY ON TERBIUM SENSITIZED CHEMILUMINESCENCE OF PIPEMIDIC ACID AND ITS APPLICATION

ABSTRACT A flow-injection chemiluminescence (CL) analysis for determination of pipemidic acid (PPA) is developed. It is based on luminescence produced by Ce(IV)–Na2SO3 CL system sensitized by Tb(PPA)2 3+. The relative chemiluminescence intensity of the Tb3+–PPA–Ce(IV)–Na2SO3 system is proportional to the amount of PPA. The optimized experimental conditions were determined. Accordingly, chemiluminescent method for the determination of PPA is proposed. The linear range and detection limit for PPA are 3.0 × 10−9–8.0 × 10−7 mol/L and 6.7 × 10−10 mol/L, respectively. The familiar excipients such as starch and dextrine do not cause interference. So this method can be applied to the determination of PPA in tablet. The content and recovery of PPA in urine can be directly detected without the pretreatment such as separation. And the mechanism of chemiluminescence is proposed.

Europium Sensitized Chemiluminescence Determination of Pazufloxacin Mesylate in Urine and Serum

Abstract A novel chemiluminescence (CL) flow injection method for the determination of pazufloxacin mesylate (PZFX) is described. It is based on CL of a KMnO4–Na2S2O4 system sensitized by the complex [Eu(PZFX)2]3+, and shows the intensive characteristic bands of Eu3+. The optimum conditions for CL emission were investigated. Under the optimum experimental condition, the linear range is 1.0×10−8–1.0×10−6 mol/L and the detection limit is 2.6×10−9 mol/L. The method was successfully applied to the determination of PZFX in serum and urine samples. The possible mechanism for this CL system is discussed. The project was supported by National Natural Science Foundation of China (20331010) and Natural Science Foundation of Beijing (2022007).

A lanthanide sensitized chemiluminescence method of flow-injection for the determination of ulifloxacin and prulifloxacin

A lanthanide sensitized chemiluminescence method of flow-injection was developed for the determination of a new fluoroquinolone, ulifloxacin (UFX), and its prodrug prulifloxacin (PUFX). The proposed method was based on the remarkable chemiluminescence enhancement effect of UFX (PUFX) on KMnO4−Na2S2O4−Ln(III). Tb(III) ion was chosen from lanthanides because it showed the best sensitizing effect. Under optimized experimental conditions, the relative chemiluminescence intensity was in linear relationship with UFX and PUFX concentrations in the ranges of 1.0 × 10−8 − 5.0 × 10−6 M and 9.0 × 10−9 − 5.0 × 10−6 M, respectively. The minimum detectable value and relative standard deviation were 5.5 × 10−9 M, 1.5% for UFX and 7.0 × 10−9 M, 2.9% for PUFX, respectively. The proposed method was applied to the determination of UFX in spiked human serum and urine, and of PUFX in tablets with satisfactory results. The possible mechanism of chemiluminescence was also proposed.

Flow‐injection chemiluminescence determination of ofloxacin using the Ru(bpy)2(CIP)2+−Ce(IV) system and its application

This paper reports a flow-injection chemiluminescence method for the determination of ofloxacin (OFLX) using the Ru(bpy)2(CIP)2+-Ce(IV) system. Under the optimum conditions, the relative CL intensity was proportional to the concentration of OFLX in the range 3.0 x 10(-8)-1.0 x 10(-5) mol/L and the detection limit was 4.2 x 10(-9) mol/L. The proposed method has been successfully applied to the determination of ofloxacin in pharmaceuticals and human urine. The chemiluminescence mechanism of the system is also discussed.