摘要:

A flow injection analysis study of the potentiometric selectivity of bis[4(5)-tert-butylbenzo]-21-crown-7 (D(tBB)21C7) for cesium over the other alkali metal cations and three alkaline earth cations has been conducted. A PVC matrix membrane containing D(tBB)21C7 as an ionophore was coated on the tip of a silver wire incorporated in a flow cell. No selectivity for cesium over rubidium and only low selectivity over potassium were noted. However, very high selectivities for cesium over sodium, lithium, strontium, calcium, and magnesium were observed. Selectivity of D(tBB)21C7 in the solvent extraction of alkali metal cations was determined by the picrate extraction method. The percent extraction into deuteriochloroform decreased in the order cesium, rubidium > potassium » sodium » lithium. Thus good agreement was observed between the responses of D(tBB)21C7 towards alkali metal cations in polymeric membrane electrodes and in solvent extraction.

ISSN:0003-2719    

DOI:10.1080/00032719308017422

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor

摘要:

A heterogeneous on line electrochemical enzyme immunoassay has been developed for the antiasthmatic drug theophylline using a flow injection analysis system containing a protein A immunoreactor to separate antibody bound and unbound theophylline-alkaline phosphatase. In this assay the antibody, label and sample are sequentially immobilised onto the protein A immunoreactor. The antibody-protein A and antibody-protein A label/sample reaction takes place at near neutral pH, and the complexes are eluted at acid pH. p-Aminophenyl phosphate (PAPP) and p-aminophenol (PAP) have been used as the detection system. Experimental variations such as flow rate and reactant concentration have been studied and serum theophylline has been determined by this method and good r.s.d values and % recoveries have been achieved.

ISSN:0003-2719    

DOI:10.1080/00032719308017423

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor

摘要:

It is reported an application of a biosensor based technology employing Surface Plasmon Resonance (SPR) for studies of molecular interaction in real time. An inhibition immunoassay for the detection of the herbicide atrazine has been developed. The biospecific interface is a sensor chip to which an atrazine derivative has been covalently bound. Monoclonal antibodies (Mabs) against atrazine are mixed with the sample containing herbicide, then the solution reacted with the biospecific interface. As the interaction between free antibodies and the immobilized derivative of atrazine bound to the surface proceeds, the SPR response changes inversely related to the atrazine concentration. A detection limit of 0.05 ppb of atrazine in water can be reached; the concentration range is 0–1 ppb, the analysis time is 15 minutes. After each measure the sensor chip surface can be regenerated. The analysis has been performed with standard solutions (buffer) in distilled and tap water.

ISSN:0003-2719    

DOI:10.1080/00032719308017424

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor

摘要:

A recently developed shallow-well microtiter plate, made from a specially formulated polymer that binds proteins, peptides and nucleic acids rapidly and efficiently, has been investigated for use in solid-phase immunoassays as well as for protein and phospholipid assays. The assay uses quantitation of the color intensity of a dye on the solid phase by means of a simple desk-top scanner coupled to a computer which allows the gray-scale density of the color to be easily and accurately measured. Consequently, this approach is independent of the absorption spectrum of the dye used.

ISSN:0003-2719    

DOI:10.1080/00032719308017425

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor

摘要:

A series of novel pseudo-affinity gels using synthetic, immobilized pyridinium ligands have been prepared. These gels exhibit extraordinarily high protein binding capacity and selectivity. Initial applications of these gels were directed toward the purification and quantitative, rapid determination of immunoglobulins. The results showed that these pseudo-affinity gels functionally mimic, to a high degree of similarity, the behavior of immobilized Protein A or G for immunoglobulins purification. In contrast to the labile nature of protein-based affinity gels, these immobilized pyridinium gels can withstand harsher treatments, such as prolonged exposure of the gels to proteolytic enzymes, organic solvents, acid or base and high temperatures.

ISSN:0003-2719    

DOI:10.1080/00032719308017426

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor

摘要:

A flow injection system was developed for the determination of glucose based on fiber optic chemiluminescence measurements. The hydrogen peroxide produced from the glucose oxidase catalyzed reaction was quantified by measuring the intensity of luminol chemiluminescence in the presence of excess ferricyanide. Glucose oxidase was immobilized on aminopropyl glass using glutaraldehyde and packed in a reactor. The chemiluminescence was transported to the detector using an optical fiber. The system responds linearly to glucose in the concentration range 0.20 mM up to 2.5 mM, with a relative precision of 5%. Several fruit juices were analyzed for their glucose content and the results were compared with a standard AOAC procedure.

ISSN:0003-2719    

DOI:10.1080/00032719308017427

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor

摘要:

A solid-state fibre-optic luminescent oxygen sensor was used for flow-through measurements. It acts as a transducer in a new flow-cell enzyme sensor arrangement. This arrangement comprises a flow path, sample injector, microcolumn with the immobilized enzyme, oxygen membrane and fibre-optic connector joined together to form an integral unit. Laccase enzyme was used as a recognition system which provided specific oxidation of the substrates with the dissolved oxygen being monitored. The assay procedure was optimized and performance of the new system studied. The sensor was applied to the determination polyphenol content in tea, brandy, etc. (quality control test). The sensitivity to some important phenolic compounds was tested with the view of industrial wastewater control applications.

ISSN:0003-2719    

DOI:10.1080/00032719308017428

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor

摘要:

Plasticized thin films of polyurethane (PU) mixed with poly(vinyl chloride)(PVC) or a terpolymer of poly(vinyl chloride)/(vinyl acetate)/(vinyl alcohol) (PVA) are examined as membrane matrices for the preparation of reversible optical ion sensors. Optical sensors for Na+, NH4+, Cl−and ClO4−are prepared by casting thin films of the polymer mixtures (PU/PVC (1:1 wt) and PU/PVA (4:1 wt)) containing appropriate ion carriers and pH chromophores on glass slides. The optical response properties of these membranes is essentially the same as conventional pure PVC membranes reported in the literature. However, significantly enhanced membrane adhesion to glass or silicon wafer surfaces is observed using the polyurethane based matrices, making them more suitable than PVC for use in the development of solid-state optical ion sensing devices.

ISSN:0003-2719    

DOI:10.1080/00032719308017429

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor

摘要:

A novel non-isotopic receptor binding technique for the detection of benzodiazepines is described. A benzodiazepine labeled with europium chelate was prepared and employed as a labeled ligand, and time-resolved measurements of the long lifetime fluorescence of europium chelate allowed avoidance of interference due to proteins in the receptor preparation. Experimental results demonstrate a sigmoid inhibition curve, with binding of the labeled ligand inhibited by comparable concentrations of the unlabeled drug. The proposed assay may provide a simple procedure for the measurement of benzodiazepines in biological systems and a useful tool in the screening of natural substances for new classes of benzodiazepine-like compounds.

ISSN:0003-2719    

DOI:10.1080/00032719308017430

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor

摘要:

A high performance liquid chromatographic (HPLC) method is described for the determination of xylazine in equine plasma. The drug and internal standard (pindolol) were separated on a 5 μm cyanopropyl-modified column (250 × 4.6 mm i.d.) using a buffer-acetonitrile mixture containing an ion pairing reagent. The drug and internal standard were isolated from plasma by liquid extraction into ethyl acetate. The method was validated over the concentration range 50–2000 ng/ml in plasma; the reproducibility, expressed as the mean co-efficient of variation was less than 5.0% for both between-day and within-day replicate determinations. The method was linear over the concentration range studied. No interferences were observed from endogenous plasma components and the limit of detection was 20 ng/ml. The method was successfully applied to the determination of xylazine in equine plasma in a crossover study design for pharmacokinetic measurements.

ISSN:0003-2719    

DOI:10.1080/00032719308017431

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor