摘要:

Recently there has been an increasing demand to produce systems for the detection of specific DNA sequences that are amenable to non-specialised laboratories. This demand has led to many innovative and novel approaches to DNA analysis which may collectively be termed ′new DNA technology′. Here, we review these advances in relation to their applicability for the production of a DNA biosensor. The present state of the art is described and future possibilities are considered.

ISSN:0003-2719    

DOI:10.1080/00032718708078036

出版商:Taylor & Francis Group    

年代:1987

数据来源: Taylor

摘要:

Isolated acetylcholine receptors from Torpedo nobiliana are used as recognition elements for phencyclidine (PCP), a potent hallucinogen with high affinity for the ion channel site associated with the receptor, in a novel enzyme-amplified receptor assay. A fixed amount of PCP labelled enzyme competes with free PCP for a limited number of receptor sites resulting in changes of observed enzyme activity proportional to free drug concentration. The proposed concept combines the use of receptors with an enzyme amplification step to yield an exceptionally simple and convenient assay.

ISSN:0003-2719    

DOI:10.1080/00032718708078037

出版商:Taylor & Francis Group    

年代:1987

数据来源: Taylor

摘要:

We developed and assembled a new multifunction valve for flow injection analysis. With the valve many types of injection mode could be performed and its fundamental characteristics were investigated. Especially when using the valve, a new injection mode could be performed, where many sample zones and reagent zones are injected serially or simultaneously. Although the reproducibility and the precision was slightly worse than those of other 6-way valves, the valve had many unique functions.

ISSN:0003-2719    

DOI:10.1080/00032718708078038

出版商:Taylor & Francis Group    

年代:1987

数据来源: Taylor

摘要:

A miniaturized Flow Injection system for the assay of urea in undiluted whole blood is described. Based on the optical determination of ammonia, the system incorporates a flow cell combining gas diffusion and optosensing, the separating barrier between the donor and accepting streams consisting of a sandwich of a hydrophobic gas permeable membrane and a hydrophilic membrane between which is contained a gel of covalently immobilized urease. The sample urea content is quantified by the colour change of an acid-base indicator contained within the acceptor stream. Within the physiological range the measurement is not affected by variations in the pH value, the buffering capacity or the hematocrit level of the sample solution, nor is it, due to the geometric construction of the flow cell, prone to interferences owing to the colour of the sample solution itself. The system is stable for a t least one week of continuous use.

ISSN:0003-2719    

DOI:10.1080/00032718708078039

出版商:Taylor & Francis Group    

年代:1987

数据来源: Taylor

摘要:

A photoreduction - fluorescence technique has been developed for the quantitative analysis of several dinitroaniline derivative herbicides. The photoreduction of anthraquinone - 2.6 - disulfonate by dinitroanilines generates highly fluorescent dihydroxyanthracene-2,6disulfonate, in a 20 : 80 vol/vol acetonitrile-water mixture at room temperature. Optimal irradiation times for obtaining a convenient, sensitized fluorescence signal are relatively short, ranging between 2 and 4 min.

ISSN:0003-2719    

DOI:10.1080/00032718708078040

出版商:Taylor & Francis Group    

年代:1987

数据来源: Taylor

摘要:

Colourless silver (I)-gelatin complex is quantitatively reduced by formaldehyde to yellov/ silver sol in the presence of 10 U NaQH at room temperature. The determination of formaldehyde at microgram level is possible at 440 nm in the presence of methanol, ethanol, acetone and also in the presence of various reducing agents. The molar absorptivity of the 4 -1 -1 solution is 2.16 × 10 lit mol cm with a relative standard deviation of 0.105%, a confidence limit (for 10 determinations)of 0.9 ± 0.0006 and Sandell sensitivity 1.38 × 10 μg cm−2.

ISSN:0003-2719    

DOI:10.1080/00032718708078041

出版商:Taylor & Francis Group    

年代:1987

数据来源: Taylor

摘要:

A method is presented for the trace analysis of molybdenum (VI) in standard steel sample, plant tissues, animal tissues, and natural waters. The method is based on the extractive separation of molybdenum from complex matrices by chelating it with a new reagent N-p-methoxypheny1-2-furylacrylohydroxamic acid (MFHA) into isoamyl alcohol followed by spectrophotometric determination, Eight other new hydroxamic acids were studied for the same purpose and MFHA was chosen as it was the most sensitive of these as well as the other hydroxamic acids reported previously, The method enables rapid and reliable analysis of molybdenum at ppb lelvels in environmental matrices.

ISSN:0003-2719    

DOI:10.1080/00032718708078042

出版商:Taylor & Francis Group    

年代:1987

数据来源: Taylor

摘要:

A new method for determining microquantities of zinc using o-nitrosophenol as reagent is described. The prepararion of the reagent in the laboratory is also described, because it is not available for sale. The formed complex, after additional pyridine, can be extracted with organic solvent (toluene) and zinc can be determined spectrophotometrically by measuring the absor-bance of the organic layer at 482 nm. The optimum range of concentration was found to be 0.04 μg to 0.8 μg/ml in the final dilution. By masking zinc using cyanide and thiosulphate and selective demasking by the addition of hydrated chloral, Zn can also be determined in the presence of larger amounts of interferences.

ISSN:0003-2719    

DOI:10.1080/00032718708078043

出版商:Taylor & Francis Group    

年代:1987

数据来源: Taylor

摘要:

4-DBIH and 2-HNIH react with As(III) and Sb(III) respectively, in CH3COOH medium to form colored complexes stable in presence of EDTA. As(III) and Sb(III) do not react with 2-HNIH and 4-DBIH respectively, and the Sb(III)-2-HNIH complex is extractable into isoamyl alcohol. These behaviours were used for the spectrophotometry determination of As (III) and Sb(III) in presence of several cations.

ISSN:0003-2719    

DOI:10.1080/00032718708078044

出版商:Taylor & Francis Group    

年代:1987

数据来源: Taylor

摘要:

A new, simple and selective spot test reaction For aromatic aldehyde detection is described. The sample is treated with 2-picoline methiodide in the presence of piperidine as catalyst. The maximum sensitivity is obtained by evaporating the reactants to near dryness in a boiling water-bath. The colored products varied between orange and pink. Aldehyde samples as small as 1.0. ug can be detected successfully. Interference of other carbonyl containing compounds is tolerated.

ISSN:0003-2719    

DOI:10.1080/00032718708078045

出版商:Taylor & Francis Group    

年代:1987

数据来源: Taylor