摘要:

In this paper, the determination ofAlexandrium affinein sea water was performed using piezoelectric immunosensors. In addition, we report a novel method of immobilizing antibodies on the quartz crystal immunosensors using plasma-polymerized ethylenediamine film. The films formed on the quartz crystals are extremely thin, homogeneous and incorporate amino groups. Sensors produced using this method show higher sensitivity than sensors made using conventional immobilization methods for example polyethylenimine or γ-aminopropyltrimethoxysilane.

ISSN:0003-2719    

DOI:10.1080/00032719608001478

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor

摘要:

An enzyme sensor for the detection of sulfonylurea herbicides inhibiting acetolactate synthase II (ALS) was developed using an oxygen electrode. ALS, which has an oxygen consumption side reaction, was entrapped in the matrix of PVA-SbQ polymer, and the enzyme membrane was attached to the electrode. The inhibition of side oxygen reaction of ALS II is measured as decreased consumption of O2monitored by an oxygen electrode. Preliminary results show that 10−6M herbicide concentration can be determined by this method.

ISSN:0003-2719    

DOI:10.1080/00032719608001479

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor

摘要:

L-cysteine can be modified onto a silver electrode by covalent binding through the sulphur to give very stable and long-lived chemically modified electrodes(CMEs). Hemoglobin(Hb) exhibits an excellent voltammetric response at the resulting CMEs. Linear sweep voltammetric(LSV) measurements of Hb on the CMEs reveal the existence of a linear relationship between the cathodic peak current and the concentration of Hb in the range of 5 X 10−7- 1 X 10−5mol/L. The detection limit is about 2 X 10−7mol/L. The relative standard deviation of results is 4.5% for 10 successive determinations at 2 X 10−6mol/L. Other proteins and chemicals present in samples do not interfere in the assay.

ISSN:0003-2719    

DOI:10.1080/00032719608001480

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor

摘要:

We determined serum bretylium levels using a bretylium-selective electrode, constructed by incorporating sodium tetrakis[3,5-bis(2-methoxyhexafluoro-2-propyl)phenyl]borate as an ion-exchanger and 2-fluoro-2′-nitrodiphenyl ether as a solvent mediator in a poly(vinyl chloride) membrane matrix. The detection limit was 0.4 μM and the sensitivity completely covered the bretylium concentration range (2-12 μM) required for antiarrhythmic therapy. The results correlated well with those obtained by conventional gas chromatographic analysis. The potentiometric procedure is simple, rapid, economical and, thus, useful for therapeutic drug monitoring in a clinical setting.

ISSN:0003-2719    

DOI:10.1080/00032719608001481

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor

摘要:

A new reliable semi-automatic procedure for enzyme immobilization in uniform calcium alginate beads is introduced, and a simple, low-cost measuring kinetic technique for enzymatic analysis is presented. Immobilized glucose oxidase, in calcium alginate beads, was used to catalyze the glucose oxidation reaction. The reaction was monitored photometrically at 460nm, by means of an indicator reaction based on the oxidation of o-dianisidine by hydrogen peroxide, in the presence of peroxidase. Under optimum conditions, the enzyme-gel beads show a good behaviour for at least two months and for at least 20 consecutive measurements on the same sample. The method was applied to the determination of glucose in foodstuffs like honey, artificial beverages, ice-cream toppings, and the results were compared with those obtained by two standard methods.

ISSN:0003-2719    

DOI:10.1080/00032719608001482

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor

摘要:

Various crown ethers have been electropolymerized onto a platinum electrode for the determination of catechol and catecholamines by static potentiometry and potentiometric-flow injection analysis(FIA). The response mechanism of this modified electrode was investigated by scanning electron microscopy (SEM), electron dispersive X-ray analysis (EDAX), and electron spectroscopy for chemical analysis(ESCA). However, these studies were not conclusive with respect to possible mechanisms, and, therefore, nuclear magnetic resonance (NMR) studies were carried out on similar soluble crown ethers to determine the mode of interaction. As the crown ether resonances were shifted to higher fields by the added catechol in D2O but not d6-DMSO, it is postulated that the crown ether and catechol associate via interactions between hydrophobic surfaces. Hydrophilic ascorbic acid showed no NMR shifts which is consistent with its lack of potentiometric response. The EDAX and ESCA results indicated that there was also an interaction of catechol with the crown itself but the NMR shows that this interaction is a secondary effect in the overall electrode response.

ISSN:0003-2719    

DOI:10.1080/00032719608001483

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor

摘要:

Urinary calculi containing triamterene were described since 1979. We have studied calculi, obtained from an anuric patient, by surgery. This paper describes the advanced techniques that were used, such as infrared spectroscopy, nuclear magnetic resonance, mass spectrometry associated with thin-layer chromatography or gas chromatography, to show the presence of unusual compounds. Six metabolites are found, among them pure triamterene (96%), hydroxy-triamterene, and a particular metabolite containing glucuronic acid.

ISSN:0003-2719    

DOI:10.1080/00032719608001484

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor

摘要:

A simple and sensitive method for the spectrophotometric determination of bio-active compounds (drugs and non-nutritive sweeteners) containing reactive functional groups, viz., aromatic primary amine (drugs: Dapsone, Sulphamethoxazole), aromatic secondary amine (drug: Pindolol), aliphatic secondary amine (non-nutritive sweetener: Cyclamate), acid hydrazide (drug: Isoniazid) and thiol (drug: Captopril), is proposed. The method involves the addition of excess of sodium nitrite to the compound in the presence of 0.25 M hydrochloric acid solution and the unreacted nitrous acid is determined by the measurement of corresponding decrease in the absorbance of cresyl fast violet acetate (Δmax: 555 nm), the most suitable one out of several dyes tested. This method was applied for the determination of bio-active compounds in commercial samples. (drugs: pharmaceutical formulations; non-nutritive sweetener (cyclamate): foodstuffs). The newly proposed method enabled the determination of the bio-active compounds in microgram quantities (0.1 - 0.5 μg/ml). Standard deviation values evaluated through replicate determinations were found to be < 0.5 mg per dose (RSD : 0.5 - 1.2%). The common excipients do not effect the determination of the drugs in pharmaceutical formulations. Many of the usually occurring additives in food stuffs are tolerated to a very high level in the determination of cyclamate in beverages, syrup, ice candy and ice cream. The validity of the method was tested against the reference method. Recoveries to the tune of 99.2 - 101.1% were observed by adopting this method.

ISSN:0003-2719    

DOI:10.1080/00032719608001485

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor

摘要:

A mathematical method that avoids spectral interferences in creatinine determination in plasma by the Jaffé reaction is proposed. The experimental conditions are studied and the accuracy and precision of the method are tested against two reference methods. The proposed method provides good results and it is suitable for creatinine determination in plasma.

ISSN:0003-2719    

DOI:10.1080/00032719608001486

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor

摘要:

A rapid, sensitive and simple procedure has been developed for determination of argininosuccinate (ASA). The assay is based upon the enzymatic cleavage of ASA in the presence of excess of argininosuccinate lyase (ASAL), HPLC separation and UV-detection of fumarate formed. The calibration curve, obtained using standards, derives from a linear correlation between the reaction rate and ASA concentration. The range of HPLC detection corresponds with the level of normal excretion of argininosuccinate in urine from the patients with argininosuccinate lyase deficiency (ASLD).

ISSN:0003-2719    

DOI:10.1080/00032719608001487

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor