摘要:

This paper reports the potentiometric measurement of ascorbic acid in the solution of 0.10 mol/L NaOH-0.1 mol/L NaCl using carbon paste (the mixture of spectroscopic graphite powder and di-iso-octyl phthalate) electrode(room temperature 15°C), with the linear range 7.0 × 10−7× 4.0 × 10−5mol/L, average response slope 95mV/decade and detection limit 1 × 10−7mol/L. Phenol, sulfite, Mn2+and so on pose no interference to the measurement of ascorbic acid. This method is characterized by fine selectivity, reproducibility and accuracy. The potential response behavior is caused chiefly by chemisorption of ascorbic acid to the surface of the carbon.

ISSN:0003-2719    

DOI:10.1080/00032719508000370

出版商:Taylor & Francis Group    

年代:1995

数据来源: Taylor

摘要:

A miniaturized thermal flow injection analysis biosensor has been coupled with a microdialysis probe for continuous subcutaneous glucose monitoring. Thermal biosensors are based on the principle of measuring the heat evolved during enzyme catalysed reactions. The system presented here consists of a miniaturized thermal biosensor with a small column containing coimmibolized glucose oxidase and catalase. The analysis buffer passes through the column at a flow rate of 60μL/min via an 1μL sample loop which is connected to a microdialysis probe.

ISSN:0003-2719    

DOI:10.1080/00032719508000371

出版商:Taylor & Francis Group    

年代:1995

数据来源: Taylor

摘要:

The biocatalytic activity of catalase in non-aqueous environments is exploited for developing an organic-phase amperometric biosensor. The catalase is immobilized within the Eastman-AQ film on the glassy carbon surface. Various experimental variables influencing the response of the t-butyl hydroperoxide substrate are explored for optimum performance.

ISSN:0003-2719    

DOI:10.1080/00032719508000372

出版商:Taylor & Francis Group    

年代:1995

数据来源: Taylor

摘要:

Opioid peptides morphiceptin (Tyr-Pro-Phe-Pro-NH2), [D-Ala2, D-Leu5]-enkephalin (Tyr-D-Ala-Gly-Phe-D-Leu, DADLE) and [D-Thr2]-Leu-enkephalin-Thr (Tyr-D-Thr-Gly-Phe-Leu-Thr, DTLET) containing tyrosine has been studied in the reaction with mushroom tyrosinase immobilized on Clark-type oxygen electrode. A 4–6-times higher response is observed for tyrosine compared to peptides. The detection limit of the tyrosinase-modified electrode for DADLE, morphiceptin and DTLET was 6 μM, 9 μM and 16 μM, respectively.

ISSN:0003-2719    

DOI:10.1080/00032719508000373

出版商:Taylor & Francis Group    

年代:1995

数据来源: Taylor

摘要:

A modified spectrophotometric method for serum glutamic-oxaloacetic transaminase (SGOT) assay was developed. A crude cell-free extract fromStreptomyces aureofacienswhich showed a high level of malate dehydrogenase (MDH) activity (E.C. 1.1.1.37) was used as the enzymatic indicator. The lyophilized microbial preparation was used without previous purification and was quite stable under refrigeration for one year. Serum sample assays using both the method utilizing the crude cell extract and an enzymatic commercial kit showed good correlation.

ISSN:0003-2719    

DOI:10.1080/00032719508000374

出版商:Taylor & Francis Group    

年代:1995

数据来源: Taylor

摘要:

The molecular imprinting technique was applied for the preparation of a polymer selective for sialic acid. To evaluate its binding ability the molecularly imprinted polymer obtained was used as a stationary phase in liquid chromatography. The polymer showed pH-dependent characteristics for binding: an optimum specificity to sialic acid at pH 8.1 and a higher affinity with group selectivity forcis-diol containing sugars at higher pH.

ISSN:0003-2719    

DOI:10.1080/00032719508000375

出版商:Taylor & Francis Group    

年代:1995

数据来源: Taylor

摘要:

We carried out the determination of cytochrome C, in solution and in the adsorbed state, using differential pulse voltammetry (DPV). The results obtained with DPV were compared with those obtained using cyclic voltammetry (CV). The influence of the nature of the electrodic material and of the different promoters was shown. It was also demonstrated that the electron transfer in solution and in the adsorbed state is quasi-reversible.

ISSN:0003-2719    

DOI:10.1080/00032719508000376

出版商:Taylor & Francis Group    

年代:1995

数据来源: Taylor

摘要:

In a recent series of papers1–3the use of dye-containing liposomes as a component of immunochemical field assay methods for the detection and measurement of environmental contaminants has been demonstrated. These assays produce a colored measurement zone on a plastic-backed nitrocellulose strip, with the amount of color in the zone being proportional to the amount of analyte present in the test sample. The color in this zone has been measured using scanning densitometry of the strips. While giving a quantitative measurement, such a system is not field-portable and cannot differentiate between multiple colors in the measurement zone. The human eye is also limited in the case of mixed colors. In this report, the use of a ColortronTM32-band digital color sensor for the quantitation measurement is demonstrated. This instrument is designed for inexpensive color analysis in the desktop publishing industry, but the fact that it can be used as a portable scanning reflectometer means that it has great potential for the spectral analysis of colors produced on a solid surface as analytical signals. As it is a scanning reflectometer rather than a single wavelength instrument, it can discriminate and quantitate a mixture of dyes, and thus has the potential to become part of a field-portable, multianalyte assay system.

ISSN:0003-2719    

DOI:10.1080/00032719508000377

出版商:Taylor & Francis Group    

年代:1995

数据来源: Taylor

摘要:

A simple, sensitive and accurate spectrophotometric procedure has been described for determination of three antihistaminic drugs, loratadine (I), dimethindene maleate (II), and clemastine hydrogen fumarate (III). The procedure is based on the interaction of each of these drugs with p-chloranilic acid (P-CA) in methylene chloride to give a stable highly coloured chromogen exhibiting maximum absorbance at 530 nm. Optimization of different experimental parameters as well as the stoichiometry of the reaction have been studied. Conformity to Beer's Law enables determination of these drugs in concentration ranges of 40–320 μg. ml−1, 40–240 μg. ml 40–400 μg. ml−1for drugs I,II and III respectively. The validity of the suggested procedure was checked by applying the standard addition technique using different pharmaceutical dosage forms. Results revealed high accuracy and good reproducibility, when compared with reference methods.

ISSN:0003-2719    

DOI:10.1080/00032719508000378

出版商:Taylor & Francis Group    

年代:1995

数据来源: Taylor

摘要:

A modified high-performance liquid chromatographic method for the quantitative determination of 6-methoxy-2-naphthylacetic acid (6-MNA), a major metabolite of nabumetone, in human serum was developed and validated. The composition of the mobile phase in Daigneault & Ferslew's method was changed in this study to improve the separation of 6-MNA from serum components. The volume ratio of acetonitrile to 1.5% acetic acid solution was changed from 60: 40 to 25: 75 in this study. As a result of the modification, the separation of 6-MNA from 2-naphtol (internal standard) and serum components was greatly improved. At a flow rate of 3.0 ml/min of the mobile phase, retention times of 6-MNA and 2-naphtol were 13 and 9 min, respectively. The detection limit was 1 μg/ml. Intra- and interday variations of the assay were <10.0 and <7.28%, respectively. Intra- and interday relative errors were <7.82 and <6.76%, respectively. 6-MNA in human serum could be determined successfully after oral administration of nabumetone (1g). Thus, the modified UV-HPLC method was confirmed to be applicable to the pharmacokinetic study of 6-MNA after oral administration of nabumetone to human subjects.

ISSN:0003-2719    

DOI:10.1080/00032719508000379

出版商:Taylor & Francis Group    

年代:1995

数据来源: Taylor