摘要:

Real-time biospecific interaction analysis (real time BIA) based on Surface Plasmon Resonance (SPR) has been used to measure the concentration of β2-microglobulin (β2-μ) and Ig E, used as a model system, simultaneously in buffer and plasma. The method relies on specific binding of β2-microglobulin and Ig E to a sensor chip surface where the monoclonal antibodies anti-β2-microglobulin and anti-Ig E were covalently immobilized. The primary binding of the analytes to the surface is followed by the injection, in sequence, of secondary antibodies, each one specific for a different epitope of β2-microglobulin and Ig E, respectively. The binding between the antibodies and the analytes is recorded as an increase in the SPR signal expressed in Resonance Units (RU). The SPR signal is directly related to the amount of β2-microglobulin and Ig E bound to the surface, and depends upon the concentration of the analytes in the sample. The analysis was performed in buffer and serum to show any non-specific binding due to serum proteins. The concentration range 0.35-5.55 nM for both analytes is covered, with good precision and close correlation with an independent standard concentration measurement.

ISSN:0003-2719    

DOI:10.1080/00032719508002669

出版商:Taylor & Francis Group    

年代:1995

数据来源: Taylor

摘要:

The potential use of plasma-deposition techniques for the preparation of recognition coatings for mass sensors was investigated. Ethylenediamine and 4-vinylpyridine plasma-produced coatings and solution-deposited coatings from commercially available polyethyleneimine and poly(4-vinylpyridine) on quartz crystal microbalances (QCMs) were examined for the detection of acetic acid and other vapors. Freshly prepared QCM plasma-deposited recognition coatings from both ethylenediamine and 4-vinylpyridine were found to be very sensitive to acetic acid vapors. However the sensitivity decreased rapidly with time. Aging effects with solution deposited polymers films were noted as well. It was concluded that plasma-deposition of recognition coatings has great potential in the preparation of recognition coatings. In addition to well known advantages of the use of plasmas for surface film preparation or modification, the technique offers a one-step process of synthesizing and depositing high molecular weight films from volatile compounds not polymerizable by conventional means. A major disadvantage is that the chemical nature of the resulting coating is not easily predictable. However, careful choice of carrier gas and recognition film precursor can do much to simplify the design of effective recognition coatings.

ISSN:0003-2719    

DOI:10.1080/00032719508002670

出版商:Taylor & Francis Group    

年代:1995

数据来源: Taylor

摘要:

A fluorescent artificial receptor previously synthesized in our group, is shown to be able to bind metal ions after dimerization. The monomer is a urea macrocyclophane: (13,21-Bis(methoxycarbonyl)-1,9,17-trioxo-2,8,16,18-tetraaza[9.3]metaorthocyclophane. The dimer is used to quantify Zn(II) through the fluorescence signal change observed upon complexation. This change can be related either to the decrease of the monomer or to the increase of the dimer forms. The response is linear for a Zn(II) concentration range between 5 and 50 μM. Specificity for Zn(II), examplified by comparison with Cd(II). was found acceptable.

ISSN:0003-2719    

DOI:10.1080/00032719508002671

出版商:Taylor & Francis Group    

年代:1995

数据来源: Taylor

摘要:

A novel strategy for preparation of solid-phase reactors is proposed. The reagent “impregnates” the inner wall of a pump tubing. The reactor is of the open-tubular type; however, the pressure of pump cylinders establish a close contact immobilized reagent-sample solution providing a high reactivity degree. The procedure is applied to iodine immobilization for fluorimetric determination of emetine, the calibration graph is linear over the range 0.1 - 100 ug ml of emetine and is applied to determination of emetine chlorhydrate in pharmaceutical formulations.

ISSN:0003-2719    

DOI:10.1080/00032719508002672

出版商:Taylor & Francis Group    

年代:1995

数据来源: Taylor

摘要:

This paper describes a potentiometric method for the determination of Cu2+in 0.1mol/L HAc-NaAc −1.0mol/L NaCl buffer, pH 5.00, using a carbon paste electrode, whose linear range is 1.0 × 10−6∼1.0×10−3mol/L with 61mV/decade of calibration slope. It exhibits high selectivity and desired reproducibility.

ISSN:0003-2719    

DOI:10.1080/00032719508002673

出版商:Taylor & Francis Group    

年代:1995

数据来源: Taylor

摘要:

A liquid membrane electrode prepared with mexiletine - dipicrylamine ion - pair complex, dissolved in nitrobenzene as solvent was studied for analytical performances. The linear response covers the range from 10−1- 10−5M mexiletine solution with a slope of 51.62mV/decade (pH range 4 to 8.0). The detection limit is 2.16 × 10−6M. The electrode showed fast response, good reproducibility and stability. The selectivity of the electrode is good. There are two strong interfering ions: ephedrine and vitamine B1. The compression excipients (Mg2+and polyvinylpyrolidone) do not interfere. An indirect potentiometric method was used to determine mexiletine as active substance with an average recovery of 100.05% and a standard deviation of 1.48% and mexiletine from drugs with an average recovery of 99.12% and a standard deviation of 1.28%. It can be also used for dissolution test. The method proved that the release of the active principle of the film coated mexiletine tablets in simulated gastric fluid followed the Fick - Higuchi model. The apparent first - order rate constants for disintegration and dissolution were calculated.

ISSN:0003-2719    

DOI:10.1080/00032719508002674

出版商:Taylor & Francis Group    

年代:1995

数据来源: Taylor

摘要:

The utility of amphiphilic pyrrole monomers to elaborate stable organic-phase polymers containing enzyme is described. Four amphiphilic pyrrole monomers differing in the size of their ammonium groups were applied to the immobilization of a preadsorbed enzyme-monomer coating.

ISSN:0003-2719    

DOI:10.1080/00032719508002675

出版商:Taylor & Francis Group    

年代:1995

数据来源: Taylor

摘要:

We describe the effect of preparation conditions during electropolymerization such as enzyme concentration in the deposition solution and film thickness on the analytical performance of the resulting polypyrrole / glucose oxidase (PPy/GOD) film. The responses of the resulting PPy/GOD biosensor to glucose and ascorbate were characterized and optimized. It was found that the enzyme concentration and the film thickness have the equivalent effects on the response of the resulting biosensor and that several optimal sets of the two parameters exist. The investigations regarding the response characteristic and the suppression of interference clearly indicate that the performance of biosensor could be significantly improved by making the film thick at low enzyme concentration.

ISSN:0003-2719    

DOI:10.1080/00032719508002676

出版商:Taylor & Francis Group    

年代:1995

数据来源: Taylor

摘要:

Flame atomic absorption spectrometry (AAS) has been used to measure magnesium (Mg2+) and potassium (K+) contents of wistar rat myocardium and skeletal muscle. Ten to twenty mg of tissue was homogenized in 10 mM hydrochloric acid, centrifuged, and the clear supernatant was diluted three-fold in deionized distilled water before determination of Mg2+and K+concentrations. The calibration curves of both ions were linear from 0.25 to 2.0 mg/L for Mg2+and from 1.5 to 15.0 mg/L for K+. The mean values (±SD) of Mg2+and K+contents for the analyzed cardiac muscle were 371.97±12.16 mg/Kg of wet tissue with a coefficient of variation (CV) of 3.3%, and 4571.02±359.74 mg/Kg with CV of 7.9%, respectively. Those for various skeletal muscles varied between 323.35-420.60 mg/Kg Mg2+, with CV ranging from 3.2% to 8.7%, and 4883.84-8156.68 mg/Kg K+, with CV ranging from 4.4% to 10.1%. The within-day CV were 2.8% to 3.8% for Mg2+and 3.2% to 5.9% for K+, whereas day-to-day CV were 6.2% to 10.2% for Mg2+and 8.7% to 10.5% for K+. Recoveries were 92.7% to 104.9% for Mg2+, and 93.2% to 106.1% for K+. Values for Mg2+ obtained by the proposed method were significantly different from those obtained by a published tissue digestion method, those for K+were not significantly different.

ISSN:0003-2719    

DOI:10.1080/00032719508002677

出版商:Taylor & Francis Group    

年代:1995

数据来源: Taylor

摘要:

A poly(methyldiallylamine-chlorohydrin) polymer was used to surface modify microporous PVDF (polyvinylidene fluoride), PTFE (polytetrafluoroethylene), and UPE (ultra high molecular weight polyethylene) membranes. These membranes were used to covalently bond hydrophilic charged carbohydrate molecules. The surfaces were characterized in terms of the structural variations of the monomer units. Immobilization occurs by a two-step process whereby strong imagewise electrostatic forces bring nucleophile (charged carbohydrate conjugate) and electrophile (membrane surface desorptive media groups) into close proximity for a pH triggered reaction to covalently bond the carbohydrate. The immobilization potential of the surfaces is described by the chlorohydrin and epoxy groups available for reaction, and is inversely proportional to the amount of alkali employed during membrane surface modification. Conjugation of complex carbohydrate mixtures to a charged fluorophore, followed by electrophoresis, transfer to the membrane surface, and immobilization produced covalently bonded bands, enabling carbohydrate structural analysis in highly desorptive media.

ISSN:0003-2719    

DOI:10.1080/00032719508002678

出版商:Taylor & Francis Group    

年代:1995

数据来源: Taylor