摘要:

Flow analysis methodology is presented for the determination of aqueous ethanol in concentrations between 3–340 μM. Alcohol oxidase catalyzes the production of hydrogen peroxide which is detected by luminol chemiluminescence. Adjustment of the pH to alkaline conditions and addition of the luminophore are implemented using in-line flow-through beds containing crystalline media. The requirement for a homogeneous catalyst is eliminated by electrochemical initiation of luminescence. Traditional laboratory reagents are replaced by packed beds containing immobilized enzyme, solid phase basification media, and crystalline luminol. The methodology is suitable for application in both continuous flow and flow injection analysis configurations.

ISSN:0003-2719    

DOI:10.1080/00032719708001666

出版商:Taylor & Francis Group    

年代:1997

数据来源: Taylor

摘要:

Some new PVC membrane electrodes based on Co(II), Mn(II), Ni(II), Cu(II), and Zn(II)chelates of bis-furfural-semi-o-tolidine as carriers are described. The electrodes exhibited different selectivity behaviour compared with the electrode using a classical anion exchanger such as tetraalkyl ammonium. The results showed that the Cobalt(II) chelate-based electrodes had a Nernstian response to iodide ion ranging from 1.0 × 10−1to 1.0 × 10−6mol.L−1in a phosphate buffer solution of pH 2.0 with a detection limit of 6.4 × 10−7mol.L−1and a slope of 57.8 mV/dec at 25deg;C. The response mechanism was also investigated by use of both a.c. impedance and SPQC techniques. The Co(II) chelate-based electrodes were used to determine the iodide content of a drug with satisfactory results.

ISSN:0003-2719    

DOI:10.1080/00032719708001667

出版商:Taylor & Francis Group    

年代:1997

数据来源: Taylor

摘要:

We have produced working fiber-optic-based biosensors that have detected aflatoxin B1(AFB1) in foods which were previously assayed with standard methods. In this study, we compare fiber-optic biosensor detection levels with those of a conventional ELISA. These detections require little specialized training of technicians, and as little as one hour to perform. AFB1concentrations were measured by several fiber-optic approaches based on fluorescence. We detected AFB1by its native fluorescence, and alternatively, in the competition mode with either FITC-labelled antibody or enzyme-labelled antibody. Extractions of AFB1from food sources (peanut and corn meal) were made and successfully tested using fiber-optics. Detection of 0.05 ng/mL AFB1was found with both of these sources using the native fluorescent format.

ISSN:0003-2719    

DOI:10.1080/00032719708001668

出版商:Taylor & Francis Group    

年代:1997

数据来源: Taylor

摘要:

A chemiluminescence(CL)-high performance liquid chromatography (HPLC) system, where CL detector was equipped with normal phase HPLC, was used in order to specifically detect lipid hydroperoxide in the heart of doxorubicin (DXR) administered mice. Luminol and cytochrome c were used as the luminescence reagents specific for the hydroperoxide. Phosphatidylcholine hydroperoxide was detected in the heart, indicating participation of lipid peroxidation in the DXR-induced cardiotoxicity. This system is of great use to study the DXR-induced lipid peroxidation in vivo.

ISSN:0003-2719    

DOI:10.1080/00032719708001669

出版商:Taylor & Francis Group    

年代:1997

数据来源: Taylor

摘要:

The oxidation of naltrexone (compound used in the treatment of opioid addiction) on carbon paste electrodes has been studied using voltammetric techniques under semi-infinite linear diffusion and hydrodynamic conditions. A simple “in situ” electrode pretreatment is proposed to obtain a good reproducibility of the current signal.

ISSN:0003-2719    

DOI:10.1080/00032719708001670

出版商:Taylor & Francis Group    

年代:1997

数据来源: Taylor

摘要:

Three new spectrophotometric methods. Vierordt's method, its modified version and the absorbancy ratio method have been used for the simultaneous determination of hydrochlorothiazide and amiloride hydrochloride in binary mixtures. Mean recoveries, relative standard deviations and linearity ranges in calibration graphs of the methods were compared. These three methods have been successfully applied to a commercial pharmaceutical preparation, a sugar - coated tablet containing hydrochlorothiazide and amiloride hydrochloride.

ISSN:0003-2719    

DOI:10.1080/00032719708001671

出版商:Taylor & Francis Group    

年代:1997

数据来源: Taylor

摘要:

Ephedrin hydrochloride reacts with sodium diphenyl amino sulfonate and potassium periodate to give a yellowish red colour having maximum absorbance at 470 nm. The reaction is selective for ephedrin with 1 μg/ml as visual limit of quantitation and provides a basis for a new spectrophotometric determination. The colour reaction obeys Beer's Law from 0.001 to 0.3 mg/ml of ephedrin. The standard deviation does not exceed 0.050 mg/ml. The method is successfully applied to pure and pharmaceutical preparations of ephedrin. The quantitative assessment of tolerable amounts of other drugs is also studied.

ISSN:0003-2719    

DOI:10.1080/00032719708001672

出版商:Taylor & Francis Group    

年代:1997

数据来源: Taylor

摘要:

Terbium(III) forms highly fluorescent complex with norfloxacin. The presence of surfactant can enhance greatly fluorescence intensity. In this paper, the fluorescence characteristics of complex in presence of surfactant has been investigated. It was found that norfloxacin could form stable complex with terbium in the pH 6.5–8.5 media. The fluorescence intensity of complex in SLS media is three folds more than complex itself. A new micelle enhancement spectrofluorimetry for the determination of norfloxacin has been developed. The detection limit of proposed method is 0.017 μg/ml. It has been satisfactory for the determination of trace norfloxacin in serum with 95.2%∼101.2% recoveries.

ISSN:0003-2719    

DOI:10.1080/00032719708001673

出版商:Taylor & Francis Group    

年代:1997

数据来源: Taylor

摘要:

Fluorimetry and photochemically induced fluorimetry (PIF) are proposed for the quantitative analysis of four psychotropic drugs, including ethopropazine (EPZ), levomepromazine (LPZ), thioproperazine (TPZ) and trifluoperazine (TFZ). The influence of ultraviolet (UV) irradiation time on the fluorescence excitation and emission wavelengths and intensity was investigated in aqueous buffer solutions (pH 4 – 6) at room temperature (298 K). The selected UV irradiation times were between 10 and 50 s, depending on the compound. Linear calibration graphs were established over about two to four orders of magnitude, with relative standard deviations in the range 2.0 – 5.4%. PIF limits of detection were comprised between 2.6 and 8 ng ml−1, depending on the compound. The PIF method was found to be more sensitive and more reliable than conventional fluorimetry for the phenothiazine derivatives under study. PIF was applied to the determination of these compounds in urine and pharmaceutical samples. The mean recoveries ranged from 88 to 119%.

ISSN:0003-2719    

DOI:10.1080/00032719708001674

出版商:Taylor & Francis Group    

年代:1997

数据来源: Taylor

摘要:

A reversed-phase HPLC method was developed for the simultaneous separation of diazepam and its achiral (nordiazepam) and chiral (oxazepam and temazepam) metabolites. Chromatographic resolution of the analytes was performed under isocratic conditions using a mobile phase of 0.3 M sodium perchlorate-acetonitrile (57:43, v/v) at a flow rate of 0.5 ml/min on a reversed-phase cellulose-based chiral stationary phase (Chiralcel OD-R column) with UV detection set at 210 nm. Disc solid-phase extraction was carried out for serum sample clean-up prior to HPLC separation. Recoveries were determined for diazepam, nordiazepam, and oxazepam and temazepam enantiomers from human serum at 300 ng/ml levels. The limits of detection were 25 ng/ml each for diazepam and nordiazepam, and about 25 ng/ml for each enantiomer of oxazepam and temazepam (S/N = 2). The method can be applicable to the in vivo analysis of human serum samples containing diazepam and its chiral and achiral metabolites.

ISSN:0003-2719    

DOI:10.1080/00032719708001675

出版商:Taylor & Francis Group    

年代:1997

数据来源: Taylor