Lanhua Chen

Development of Cloud Point Extraction for Simultaneous Extraction and Determination of Platinum and Palladium Using Inductively Coupled Plasma Optical Emission Spectrometry in Platinum-Palladium Spent Catalysts

A new on-line cloud point extraction system coupled to inductively coupled plasma optical emission spectrometry was designed for simultaneous extraction, preconcentration and determination of trace amounts of platinum and palladium in platinum-palladium spent catalysts. This was based on the complexation of the metal ions with 1,8-diamino-4,5-bis(hydroxyamino)anthraquinone reagent in the presence of non-ionic surfactant of Triton X-114. After phase separation, the surfactant-rich phase was diluted with concentrated HNO3 (70%, w/w); the analytes concentrations were determined by inductively coupled plasma-optical emission spectrometry. Several factors influencing the instrumental conditions and extraction were evaluated and optimized. Under the optimum conditions, the enhancement factors of the proposed method were 35.4 and 29 for platinum and palladium, respectively. The detection limits were 0.3 and 0.45 µ g L−1. Finally, the developed method was successfully applied to the extraction and determination of platinum and palladium in platinum-palladium spent catalysts samples and satisfactory results were obtained.

A Direct Chemiluminescence Method for the Determination of Prulifloxacin Using Tris-(4,7-Diphenyl-1,10-Phenanthrolinedisulfonic Acid) Ruthenium(II)–Cerium(IV) System

Abstract A simple, rapid, injection chemiluminescence method is described for the determination of prulifloxacin, a commonly used antibiotic. A strong chemiluminescence signal was detected when a mixture of the analyte and tris-(4,7-diphenyl-1,10-phenanthrolinedisulfonic acid)ruthenium(II) was injected into cerium(IV) sulfate. The chemiluminescence signal is proportional to the concentration of prulifloxacin in the range 4.0 × 10−8–9.0 × 10−6 mol L−1. The detection limit is 1.0 × 10−8 mol L−1, and the relative standard deviation is 2.2% (n = 11) for the determination of 8.0 × 10−7 mol L−1 prulifloxacin. The proposed method was successfully applied to the determination of prulifloxacin in pharmaceutical preparations in capsules, spiked serum, and urine samples.

Flow-Injection Chemiluminescent Determination of Piroxicam Using Tris (2,2′-bipyridyl) Ruthenium(II)—Potassium Permanganate System

Abstract A rapid and sensitive chemiluminescence method using flow-injection has been developed for the determination of an analgesic agent drug, piroxicam. The method is based on the chemiluminescence reaction of piroxicam with an acidic potassium permanganate and Ru(bipy)3 2+. The chemiluminescence intensity is greatly enhanced when quinine sulfate is used as a sensitizer. After optimization of the different experimental parameters, a calibration graph was obtained over a concentration range of 3.0 × 0−8–3.0 × 0−5 mol L−1 with the detection limit of 1.0 × 0−8 mol L−1. The relative standard deviation is 1.5% (n = 11) for the determination of 8.0 × 10−7 mol L−1 piroxicam. The proposed method was successfully applied to commercial tablets, spiked serum, and urine samples.

Chemiluminescence method for the determination of piroxicam by the enhancement of the tris-(4,7-diphenyl-1,10-phenanthrolinedisulphonic acid) ruthenium(II) (RuBPS)-cerium(IV) system and its application.

A simple, rapid chemiluminescence (CL) method was described for the determination of piroxicam, a commonly used analgesic agent drug. A strong CL signal was detected when cerium(IV) sulphate was injected into tris-(4,7-diphenyl-1,10-phenanthrolinedisulphonic acid) ruthenium(II) (RuBPS)-piroxicam solution. The CL signal was proportional to the concentration of piroxicam in the range 2.8 x 10(-8)-1.2 x 10(-5) mol/L. The detection limit was 2 x 10(-8) mol/L and the relative standard deviation (RSD) was 3.7% (c = 7.0 x 10(-7) mol/L piroxicam; n = 11). The proposed method was applied to the determination of piroxicam in pharmaceutical preparations in capsules, spiked serum and urine samples with satisfactory results.

Highly Sensitive Spectrofluorimetric Determination of Trace Amounts of Superoxide Dismutase Using a Prulifloxacin-Terbium(III) Probe

Abstract A new spectrofluorimetric method was developed for determining superoxide dismutase. The interactions between prulifloxacin (PUFX) –Tb3+ complex and superoxide dismutase had been studied by using UV-Vis absorption and fluorescence spectra. Using prulifloxacin–Tb3+ as a fluorescence probe, under optimum conditions, superoxide dismutase could remarkably enhance the fluorescence intensity of the prulifloxacin–Tb3+ complex at λ = 545 nm, and the enhanced fluorescence intensity was in proportion to the concentration of superoxide dismutase. Optimum conditions for the determination of superoxide dismutase were also investigated. The dynamic range for the determination of superoxide dismutase was 0.032 to 22.56 µg mL−1, and the detection limit (S/N = 3) was 1.5 ng 4 mL−1. This method was simple, practical, and relatively free of interference from coexisting substances and could be successfully used to determine superoxide dismutase in the plant and blood samples. The mechanism of fluorescence enhancement of prulifloxacin–Tb3+ complex by superoxide dismutase was also discussed.

Enoxacin—Tb3+ Complex as an Environmentally Friendly Fluorescence Probe for Coenzyme A and Its Application

Abstract A new spectrofluorimetric method was developed for the determination of trace amounts of coenzyme A using enoxacin–Tb3+ as a fluorescent probe. In the presence of periodic acid (H5IO6), coenzyme A could remarkably enhance the fluorescence intensity of the Tb3+–enoxacin complex at 545 nm at pH 5.4. The optimal conditions for the determination of coenzyme A were also investigated. This method could be successfully applied to assess coenzyme A in injection and biological samples. Moreover, the enhancement mechanism of the fluorescence intensity of the coenzyme A–Tb3+–enoxacin system in the presence of H5IO6 was also discussed.

Determination of Coenzyme II Using Balofloxacin–Terbium(III) as a Fluorescence Probe by Spectrofluorometry

Abstract A new spectrofluorometric method was developed for determination of coenzyme II. We studied the interactions between balofloxacin–terbium(III) complex and coenzyme II by using ultraviolet–visible absorption and fluorescence spectra. While balofloxacin–terbium(III) was used as a fluorescence probe, under the optimum conditions, coenzyme II could remarkably enhance the fluorescence intensity of the balofloxacin–terbium(III) complex at λ = 545 nm, and the enhanced fluorescence intensity was in proportion to the concentration of coenzyme II. Optimum conditions for the determination of coenzyme II were also investigated. The dynamic range for the determination of coenzyme II was 6.0 × 10−8 to 6.0 × 10−6 mol L−1, and the detection limit (3σ/k) was 3.5 × 10−8 mol L−1. This method was simple, practical, and relatively free interference from coexisting substances and could be successfully applied to determination of coenzyme II in synthetic samples. The mechanism of fluorescence enhancement of balofloxacin–terbium(III) complex by coenzyme II was also discussed.