Analytical Letters

Ryabov, Alexander D.; Ivanova, Marina; Gnedenko, Boris B.; Valunas§, R.

doi: 10.1080/00032719408000294pmid: N/A

Abstract A simple procedure is described for co-immobilization of glucose oxidase and dimethylaminomethylferrocene in a sodium alginate gel on the surface of pyrolytic graphite electrode. The film is electrochemically active and the peak current is a function of D-glucose concentration with the apparent Michaelis-Menten constant Km = (1.2±0.3) × 10−2 M. The optimal concentration range for biosensoric applications in 0.001–0.010 M. §On leave from the Institute of Applied Enzymology FERMENTAS, Vilnius, Lithuanian Republic.

Bogdanovskay, V. A.; Fridman, V. A.; Tarasevich, M. R.; Scheller, F.

doi: 10.1080/00032719408000295pmid: N/A

Abstract Electrocatalytic reduction of hydrogen peroxide by peroxidase immobilized throughits adsorption at carbon black was studied by using the rotating disk electrode technique. The reaction mechanism was proposed on the basis of experimental data concerning the influence of various parameters on the reaction rate: H2O2 concentration, the electrode rotation speed, solution pH, inhibitors and activators. The mechanism was found to be similar to that of peroxidase catalysis in the bulk of the solution, the electrode acting as aromatic reducer substrate. The results obtained on inhibition and activation of H2O2 electroreduction allows us to give recommendation on the electroanalytical detection of CN−, F− ions and bensotriasol.

Simonian, A. L.; Badalian, I. E.; Berezov, T. T.; Smirnova, I. P.; Khaduev, S. H.

doi: 10.1080/00032719408000296pmid: N/A

Abstract Amperometric flow-injection analytical system for quantitation of low L-lysine concentration was described. L-lysine-α-oxidase from Trichoderme sp. was immobilized by covalent linking on silica gel. The shift in oxygen concentration during enzymatic reaction was detected with a Clark membrane electrode. The rate of oxygen consumption was linearly dependent on L-lysine concentration over the 0,20 - 5,5 mM. Response time was 14 s, the total assay time about 2 min. The influences of pH, ionic strength and nature of the buffer on enzyme catalytic activity were tested. The analysis conditions were optimized. The immobilized L-lysine-α-oxidase retained the catalytic activity for about 5 months.

Karyakin, Arkady A.; Gitelmacher, Olga V.; Karyakina, Elena E.

doi: 10.1080/00032719408000297pmid: N/A

Abstract A first generation amperometric glucose biosensor based on Prussian Blue modified electrodes was developed. Besides exception of noble metals (platinum as usual) the developed biosensor possessed high sensitivity. Linear response dependence on analyte concentration was observed in a range of 10−6 − 5·10−3 M glucose. The current density produced by addition of 10−6 M glucose was 0.18 μ A/cm2. Hydrogen peroxide produced via enzyme reaction was detected by electroreduction. Owing to that reason the biosensor response became independent of the presence of reductants (ascorbate for example). The developed amperometric biosensor was expected to obey requirements for non-invasive diagnostics. There are not principle limits of using other oxidases for Prussian Blue based amperometric biosensor development. Thus one can develop such biosensors for cholesterol, alcohol, glycerol, amino acids ets.

Karyakina, Elena E.; Neftyakova, Lylia V.; Karyakin, Arkady A.

doi: 10.1080/00032719408000298pmid: N/A

Abstract Application of polyaniline semiconductor films to potentiometric biosensor development provides certain advantages comparing with the known systems. Using self-doped polyaniline instead of common polymer as pH transducer the stable potentiometric response of 70 mV/pH was obtained. Taking as an example glucose biosensor we showed that polyaniline based electrode possessed three-four fold increased potential shift than glucose-sensitive field-effect transistor did. One can increase the sensitivity of potentiometric biosensor using thick ion-exchange membranes (in our case Nafion) in order to concentrate product near electrode surface. Such sensor possessed higher response time.

Shekhovtsova, Tatyana N.; Chernetskaya, Svetlana V.

doi: 10.1080/00032719408000299pmid: N/A

Abstract New test method and test device for the mercury (II) determination at the pg/mL level were developed based on the mercury inhibitory action on horseradish peroxidase immobilized on solid supports – in the cells of the polystyrene plate and on the chromatographic paper. The reactions of o-dianisidine, 3,3′,5,5′-tetramethylbenzidine and o-phenylenediamine oxidation by hydrogen peroxide were used as the indicator reactions. The mercury inhibitory effect increased in the presence of thiourea. Under the elucidated optimal conditions the calibration curves for the mercury determination showed a linear relationship between the peroxidase inhibition degree and the mercury concentration in the range of 0,1–1000 pg/mL. The mercury detection limits were 0,1–10 pg/mL in dependence on the concrete indicator reaction. The analysis completed in 15 min. The proposed test device was applied to the mercury determination in underground waters of Moscow region. The mercury content obtained was coincident with that obtained by atomic-fluorescent method with cold vapour.

Osipov, Alexander P.; Gaponova, Natalia K.; Dzantiev, Boris B.

doi: 10.1080/00032719408000300pmid: N/A

Abstract New high-sensitive visually controlled membrane-type analytical methods are proposed for quantitation of nicotineamide adenine dinucleotide and alkaline phosphatase in water solutions. The methods are based on using nitrocellulose membrane as a solid matrix on which the components of one-enzyme cofactor regeneration system are being immobilised by adsorption. In the presence of substances to be assayed, the end colored product is being adsorbed on the matrix as a result of enzymatic cyclic NAD/NADH regeneration in the active site of the matrix-bound alcohol dehydrogenase and some chemical successive reactions. Its colored intensity is a measure of the concentration of the analysed substances in solution. The general principle of NAD or alkaline phosphatase determination is successive immobilisation of separate components of the system (N-(6′-aminohexyl)salicylamide and horse liver alcohol dehydrogenase) on the matrix by adding their solutions to the wells of a specially designed cell with the membrane bottoms. In the case of alkaline phosphatase, the enzyme acted on NADPH as on a substrate. The reaction product, NAD was detected in the subsequent reaction of coenzyme regeneration. The other components of the amplifying system were added in substrate solutions at the stage of the alcohol dehydrogenase reaction. The lower detection limits for NAD and alkaline phosphatase were 3 × 10−9 M and 1 × 10−14 M respectively, the volume of the test sample − 20 μl, the time of assay − 5 min. The working concentration ranges were from 3 × 10−9 to 1 × 10−7 M and from 1 × 10−14 to 1 × 10−10 M levels for NAD(H) and alkaline phosphatase, respectively.

Gazaryan, I. G.; Loginov, D. B.; Lialulin, A. L.; Shekhovtsova, T. N.

doi: 10.1080/00032719408000301pmid: N/A

Abstract Peroxidases of different origin — horseradish peroxidase isozyme C, alfalfa and peanut cationic peroxidases, tobacco leaves and novel fungal anionic peroxidases – were used to determine phenol and its analogues. Phenol and resorcinol were shown to be the inhibitors of the peroxidase activity towards o—dianisidine for all the enzymes tested, whereas pyrogallol and hydroquinone caused an appearance of a lag—period on a kinetic curve. The duration of a lag—period was proportional to the effector concentration and could be used to determine it. The novel fungal peroxidase from Phellinus igniarius exhibited the highest sensitivity towards phenols and they could be determined at the 10–6 – 10–7 M concentration levels.

Kudryasheva, N. S.; Kratasyuk, V. A.; Belobrov, P. I.

doi: 10.1080/00032719408000302pmid: N/A

Abstract The physical-chemical regularities of aromatic compounds' effects in luciferase toxicity biotesting have been studied. The structures and physical-chemical characteristics of the toxicants and of the bioluminescent emitter were taken into account. The inhibition constants of bioluminescence intensiy (I) were calculated and interpreted from the viewpoint of the energy (electron) transfer processes. The induction period (P) and the increase of the time of the maximum light intensity (tM) which take place in the quinones' presence, have been shown to deal with hydrogen transfer processes. The values of I, P and tM have been shown to be connected with a size of the quinones' aromatic and aliphatic parts. P- and tM-dependencies on quinone's redox potential have been demonstrated.

Brovko, L. Yu.; Dementieva, E. I.; Aronova, E. A.; Yevseev, P. V.; Ugarova, N. N.

doi: 10.1080/00032719408000303pmid: N/A

Abstract Bioluminescent method for β-galactosidase assay is proposed with sensitivity as high as 0.25 fmol/1 with the help of bioluminogenic substrate – firefly luciferin derivative. Method was applied to immunoassay of foot-and-mouth disease viral antigen and biotinylated DNA-probe analysis with the help of β-galactoside labelled conjugates. Methods proved to be very sensitive, rapid and simple in performance. Photographic detection and reprobing of the samples are possible.