摘要:

A report on the status of the quartz crystal microbalance (QCM) technique for applications in biochemistry, food, environmental and clinical analysis is presented. With the advent of pre-coated crystals, used in a flow cell with the microprocessor controlled PZ 106 Immunobiosensor System, assays can be performed with the QCM in a manner equivalent to the SPR (surface plasmon resonance) technique both in sensitivity and selectivity.

ISSN:0003-2719    

DOI:10.1080/00032719508001422

出版商:Taylor & Francis Group    

年代:1995

数据来源: Taylor

摘要:

Three monoclonal antibodies (mab) for the determination of the pyrethroid insecticide allethrin were generated using a trans-permethric acid-bovine serum albumin conjugate as immunogen. Spleen cells of immunized BALB/c mice were fused with myeloma cells applying polyethylene glycol. Hybridoma cells were selected by HAT selection and screened for cell lines producing mab. Three stable cell lines could be isolated for further characterization and development of an indirect competitive enzyme immunoassay. The mab 3/B4-1/F8 showed a preference for S-bioallethrin, the most efficient insecticidal isomer of allethrin. The detection range lay between 1 μg/L and 250 μg/L; 50 % inhibition occurred at 46 μg/L. Cross-reactivities were 43 % for the natural pyrethrins. The mab 1/E2-5/B5 and 1/A5-7/C10 preferred bioallethrin, which is a mixture of two allethrin enantiomers. 50 % inhibition was found at 60 μg/L or 54 μg/L, respectively. The tests ranged from 9 μg/L to 170 μg/L (1/E2-5/B5) and from 6 μg/L to 160 μg/L (1/A5-7/C10). Cross-reactivities occurred for phenothrin, resmethrin and bioresmethrin.

ISSN:0003-2719    

DOI:10.1080/00032719508001423

出版商:Taylor & Francis Group    

年代:1995

数据来源: Taylor

摘要:

An enzyme immunoassay was developed for the simultaneous detection of different pyrethroid insecticides. Several polyclonal antisera were raised in rabbits using 1R trans-permethric acid coupled to bovine serum albumin (BSA) as immunogen. Antiserum D12 recognized permethrin, cyfluthrin, cypermethrin. S-bioallethrin and the metabolite 1R trans-permethric acid with similar affinities. 50 % inhibition (50 % B/B0) for permethrin occurred at 8 μg/L; linearity ranged between 0.4 and 74 μg/L. The antisera D5 and D7 were obtained from preceding blood samples, and the antibodies showed different cross-reactivities, revealing the path of affinity maturation of the antiserum.

ISSN:0003-2719    

DOI:10.1080/00032719508001424

出版商:Taylor & Francis Group    

年代:1995

数据来源: Taylor

摘要:

We have developed sensitive, non-isotopic immunoassays for cholecystokinin (CCK) by using colorimetric, time-resolved fluorometric and chemiluminometric detection. The assay is based on competition between a free CCK and biotinylated CCK-33 as tracer for rabbit anti-CCK-8 antibodies on a goat anti-rabbit IgG antibody coated microtiter plate. After separation of bound and free fractions, a solution of streptavidin-horseradish peroxidase conjugate (SA-HRP) or europium (III) ion chelate labeled SA (Eu-SA) was added to the biotinylated CCK-33 bound on the microtiter plate. The microtiter plate was washed and then the SA-HRP activity was measured by colorimetry or chemiluminometry and the Eu-SA activity was measured by time-resolved fluorometry, respectively. Detection limits of CCK-8 were 1000 pg/mL by colorimetry, 125 pg/mL by time-resolved fluorometry, and 1.95 pg/mL by chemiluminometry, respectively. Further, the sensitivity of the concentration yielding 50% inhibition value obtained by using a signal amplification method, catalyzed reporter deposition (CARD), was 135.7-fold by colorimetry, 18.5-fold by time-resolved fluorometry and 1.5-fold by chemiluminometry, better than that obtained without CARD.

ISSN:0003-2719    

DOI:10.1080/00032719508001425

出版商:Taylor & Francis Group    

年代:1995

数据来源: Taylor

摘要:

A new amperometric electrode for the assay of lactate dehydrogenase (LDH) is prepared by modifying a nanometer—sized microband gold electrode with nickel hexacyanoferrate. The amperometric determination bases on electrochemically detecting NADH produced by the enzymatic reaction of lactate with NAD+under the catalysis of LDH. The modified electrode can sensitively detect LDH at +0.55V vs. SCE with a linear response in the range of 10U / mL to 350U / mL under optimum conditions.

ISSN:0003-2719    

DOI:10.1080/00032719508001426

出版商:Taylor & Francis Group    

年代:1995

数据来源: Taylor

摘要:

An FIA method for the determination of calcium pantothenate, one of the components of vitamin B complex, is proposed. The method is based on the alkaline hydrolysis of the analyte to β-alanine and subsequent derivatization to a 1-alkylthio-2-alkylisoindole, the fluorescence of which is monitored at λex= 350 nm and λem= 455 nm. Chemical and physical variables influencing the fluorescence signal were optimized and the method was validated as regards accuracy, repeatability and reproducibility. The proposed method features a broad linear determination range (0.2–40 mg/L) and a throughput of 25 samples/h. It was applied to the determination of calcium pantothenate in multivitamin preparations with satisfactory results.

ISSN:0003-2719    

DOI:10.1080/00032719508001427

出版商:Taylor & Francis Group    

年代:1995

数据来源: Taylor

摘要:

The possibility of crown ethers: 18 - crown - 6 (18C6), benzo - 18 - crown - 6 (B18C6), dibenzo - 18 - crown - 6 (DB18C6) and cryptand 222 (222) to form complexes with the cationic species of a series of α - amino acids in the protonated form (L - leucine, L - isoleucine, L - phenylalanine, L - methionine, L - valine and L - α-alanine) has been investigated. These cationic complexes can be extracted in chloroform, as ion pair complexes using pirate anion as counterion. The extraction constants have been determined by UV - Vis absorption method and they are in the 4.2 - 5.28, 4.19 - 4.54, 3.5 - 4.25, and 4.15 - 4.49 ranges when 18C6, B18C6, DB18C6 crown ethers, and 222 cryptand, respectively are used.

ISSN:0003-2719    

DOI:10.1080/00032719508001428

出版商:Taylor & Francis Group    

年代:1995

数据来源: Taylor

摘要:

We describe here the automatic switching of the electric field for PFGE systems to simultaneously control at least two PFGE experiments. For this purpose an IBM interface card was designed, that demands the execution of a specially programmed service routine based on the interruption technique. The interface card is commanded by a software program that contains a memory resident module to report the status of the electrophoresis. The approach also allows the construction of simpler switching units than those currently used. The system facilitates the study of DNA migration under different electrode geometries without disturbing the computer routine tasks. The system was validated by running simultaneouslySaccharomyces cerevisiaechromosomes and λ Hind III restriction fragments in CHEF and TAFE systems.

ISSN:0003-2719    

DOI:10.1080/00032719508001429

出版商:Taylor & Francis Group    

年代:1995

数据来源: Taylor

摘要:

Each one of four very slightly water-soluble to practically water-insoluble, non-steroidal anti-inflammatory, antipyretic and analgesic drugs, such as indomethacin(I), aspirin(II), ibuprofen(III) and flurbiprofen(IV) were dissolved in a N-hexadecyl-N, N, N-trimethylammonium bromide (CTAB) micellar medium and the resulting solutions were titrated with a carbonate-free 2.5 mmol/L NaOH solution. The end point determined potentiometrically by the convetional manner, using the second derivative graph, while the routine analytical applications were carried out either by an automatic titration assembly or by visual titration using the selected acid-base indicator. Results for(I–IV) agreed well with those obtained by the method of the USP XXII and a statistical analysis by means of Student's t-test, as well as by the variance ratio F-test proved that between the proposed method and the official one no significant difference was observed. The method described in the present paper, is simple, precise, inexpensive and it could successfully replace the established non-aqueous techniques.

ISSN:0003-2719    

DOI:10.1080/00032719508001430

出版商:Taylor & Francis Group    

年代:1995

数据来源: Taylor

摘要:

Streptomycin reacts with ninhydrin in alkaline medium to give a violet colour having maximum absorbance at 560 nm. The reaction is specific for streptomycin with 0.1 μg/ml as minimum limit of detection. It also provides the basis for a new spectrophotometric determination of pure streptomycin and in the presence of the organic compounds. The maximum tolerable limits of these are reported. The method is successfully applied to the determination of streptomycin from pharmaceutical preparation.

ISSN:0003-2719    

DOI:10.1080/00032719508001431

出版商:Taylor & Francis Group    

年代:1995

数据来源: Taylor