Deyong He

Molecularly imprinted on-line solid-phase extraction combined with flow-injection chemiluminescence for the determination of tetracycline

A molecularly imprinted polymer solid phase extraction (MISPE) method combined with flow-injection chemiluminescence (FI-CL) for the determination of residual tetracycline (TC) in fish samples is presented. The molecularly imprinted polymer (MIP) of TC was synthesized and particles of this MIP were packed into a polytetrafluoroethylene (PTFE) tube, which was connected into the sampling loop of an eight-way injection valve and served as the MISPE column for on-line selective adsorption of TC. The eluent (CH3CN : HNO3 (0.01 mol L(-1)) = 4 ratio 1, v ratio v) was used for extracting the adsorbed TC, which could be detected by its good enhancing effect on the CL reaction between Ce(iv) and rhodamine B. The CL intensity is linear to TC concentration in the range from 4 x 10(-9) to 4 x 10(-7) g mL(-1). The detection limit is 1 x 10(-9) g mL(-1) (3 sigma) and the relative standard deviation is 2.4% (n = 9). The conditions of preconcentration, extraction and CL reaction were carefully studied. The selectivity experiment shows that the selectivity and sensitivity of the CL method could be improved greatly when MIP was used as a recognition material in SPE. However, the MISPE column interacted indiscriminately with oxytetracycline (OTC) with a 49 +/- 2% binding. An intermediate differential pulsed elution (DPE) step using 3% acetic acid as eluent was employed to remove OTC and other interfering substances. The proposed MISPE-CL method has been applied successfully to the determination of TC in fish samples. At the same time, the binding characteristics of the polymer to tetracycline were evaluated by batch and dynamic methods.

A novel chemiluminescence method for determination of terbutaline sulfate based on potassium ferricyanide oxidation sensitized by rhodamine 6G

This work reports a novel flow injection-chemiluminescence (FI-CL) system for determination of terbutaline sulfate, a drug for treatment of asthma and chronic obstructive pulmonary disease (COPD). It is based on the reaction of potassium ferricyanide with terbutaline sulfate in sodium hydroxide medium sensitized by the fluorescent dye rhodamine 6G. With the peak height as a quantitative parameter applying optimum working conditions, terbutaline sulfate is determined over the range of 0.01-1.2 microg ml(-1) with a detection limit of 6.7 x 10(-3) microg ml(-1). The relative standard deviation (R.S.D.) is 3.7% for 0.1 microg ml(-1) terbutaline sulfate (n = 11). The proposed method is sensitive, simple, rapid, and was applied to determination of terbutaline sulfate in pharmaceutical preparations. The possible chemiluminescence (CL) reaction mechanism was also discussed briefly.

Chemiluminescence Microflow Injection Analysis System on a Chip for the Determination of Sulfite in Food

Abstract Based on the chemiluminescence (CL) reaction between Ce (IV) and sulfite sensed by Rh6G and Tween 80 in acid medium, a new microflow injection analysis (µFIA) system on a chip for the determination of sulfite with chemiluminescence method was described in this paper. The channels of the µFIA system etched by CO2 laser were 200 µm wide and 150 µm deep and the volume of reaction area was 1.80 µL. All reagents, including sample, were monitored by the injection pump with the rate of 50 µL/min. The linear range of sulfite concentration was 1.0–60 µg/mL with the detection limit of 0.5 µg/mL. The proposed method had good reproducibility with the relative standard deviation 3.0% (n = 7) for 20 µg/mL of sulfite and was very sensitive and simple. It had been successfully applied to the determination of sulfite in food. Supported by a grant from the Science and Technique Ministry of China (2003BA310A05).

Flow Injection Chemiluminescence Method for Determination of Ribavirin Based on Enhancement of Luminol-Persulfate Reaction

Abstract A novel flow injection chemiluminescence (FI-CL) method for the determination of ribavirin is developed based on the enhancing effect of the analyte on CL emission of luminol oxidized by sodium persulfate in alkaline solution. The CL emission is correlated with the ribavirin concentration in the range from 0.01 to 1.0 µg mL−1, and the detection limit (3σ) is 0.004 µg mL−1. The relative standard deviation is 2.8% (n = 11, 0.1 µg mL−1 ribavirin). The method was successfully applied to the determination of ribavirin in pharmaceutical preparations.