Biomedical subjects

N Kiba

Publications and source records attributed to N Kiba.

11 recordsLinked to original sources

PubMed2001

Flow-through chemiluminescence sensor using immobilized histamine oxidase from Arthrobacter crystallopoietes KAIT-B-007 and peroxidase for selective determination of histamine.

A flow sensor with immobilized oxidases is proposed for the determination of histamine in fish meat. Chemiluminometric measurement of histamine was based on the luminol reaction with hydrogen peroxide produced by immobilized histamine oxidase (EC 1.4.3.-.) and peroxidase (EC 1.11.1.7.) within a flow cell. Histamine oxidase was found in cells of Arthrobacter crystallopoietes KAIT-B-007 isolated from soil. The oxidase and peroxidase were coimmobilized covalently on tresylated hydrophilic vinyl polymer beads and packed into transparent PTFE; the tubing was used as the flow cell. One assay for histamine was done at intervals of 2 min without carryover. The calibration curve for histamine was linear from 0.1 microM to 50 microM. The response was reproducible within 1.25% of the relative standard deviation for 115-replicate injections of 50 microM histamine. The sensor system was applied to the determination of histamine in fish meat extracts.

Amine Oxidase (Copper-Containing)↗

PubMed2001

Flow-through chemiluminescence sensor using immobilized oxidases for the selective determination of L-glutamate in a flow-injection system.

A selective and sensitive chemiluminometric flow sensor for the determination of L-glutamate in serum, based on immobilized oxidases such as glutamate oxidase (GOD), uricase (UC) and peroxidase (POD), is described herein. The principle for the selective chemiluminometric detection for L-glutamate is based on coupled reactions of four sequentially aligned immobilized oxidases, UC/POD/GOD/POD in a flow cell. The immobilized UC was employed to decompose urate, which is one of the major interfering components in serum for a luminol-H2O2 chemiluminescence reaction. The H2O2 produced from the UC reaction readily reacted with reducing components, such as ascorbate and glutathione, and then the excess H2O2 was decomposed by the immobilized POD. L-Glutamate in the sample plug was enzymatically converted to H2O2 with immobilized GOD. Subsequently, the peroxide reacts with luminol on the immobilized POD to produce chemiluminescence, proportional to glutamate concentration. The enzymes were immobilized on tresylated poly(vinyl alcohol beads). The immobilized enzymes were packed into TPFE tube (1.0 mm i.d. x 60 cm), in turn, and used as a flow cell. The sampling rate was 30 h-1. The calibration graph for L-glutamate is linear for 20 nM-5 microM; the detection limit (signal-to-noise = 3) is 10 nM.

Ascorbic Acid↗

PubMed2000

Poly(allylamine) beads as selective sorbent for preconcentration of formaldehyde and acetaldehyde in high-performance liquid chromatographic analysis.

Formaldehyde and acetaldehyde in water were determined by preconcentration with poly(allylamine) beads, derivatization with 2,4-dinitrophenylhydrazine (DPH) and analysis by HPLC. Poly(allylamine) beads (0.5 g) were used to adsorb formaldehyde and acetaldehyde at 1.2-150 microg l(-1) and 3.5-220 microg l(-1) from water (1 l). The concentration factor is 50 fold. The aldehydes were eluted and derivatized with 2 mM DPH in 0.5 M H2SO4 (10 ml). The time of analysis was 1 h. The detection limits (S/N=3) for formaldehyde and acetaldehyde were 0.6 and 2 microg l(-1), respectively.

Acetaldehyde↗

PubMed1997

Post-column enzyme reactors for chemiluminometric detection of glucose, 1,5-anhydroglucitol and 3-hydroxybutyrate in an anion-exchange chromatographic system.

A liquid chromatographic system consisting of a co-immobilized 3-hydroxybutyrate dehydrogenase-NADH oxidase reactor and an immobilized pyranose oxidase reactor in series and a chemiluminometer was developed for the simultaneous determination of glucose, 1,5-anhydroglucitol and 3-hydroxybutyrate in plasma. The enzymes were immobilized on toresylated poly(vinyl alcohol) beads. Separation was achieved on a TSK gel SAX column (40 x 4 mm I.D.) with an eluent of 50 mM NaOH containing 30 mM sodium butyrate. The hydrogen peroxide produced was detected by measuring the chemiluminescence emitted on admixing with luminol and potassium hexacyanoferrate(III). The calibration curves were linear from 0.8 to 500 microM (7 ng-4 micrograms) for glucose, from 0.8 to 400 microM (7 ng-3 micrograms) for 1,5-anhydroglucitol and from 1 to 700 microM (5 ng-4 micrograms in a 50-microliter injection) for 3-hydroxybutyrate. The sample throughput was four per hour. The reactors were stable for at least ten days.

3-Hydroxybutyric Acid↗

PubMed1996

Postcolumn co-immobilized leucine dehydrogenase-NADH oxidase reactor for the determination of branched-chain amino acids by high-performance liquid chromatography with chemiluminescence detection.

A liquid chromatographic system with a co-immobilized leucine dehydrogenase-NADH oxidase reactor is described for the determination of branched-chain amino acids such as I-leucine, I-isoleucine and I-valine. The enzymes were simultaneously immobilized on tresylate-containing poly(vinyl alcohol) beads. The separation was achieved by means of an ODS column with elution with phosphate buffer (pH 7.5). The hydrogen peroxide produced was detected chemiluminometrically via a luminol-hexacyanoferrate(III) reaction. The system gave a linear response from 0.3 to 300 mu M for each amino acid and the detection limit was 0.1 mu M.

Amino Acid Oxidoreductases↗

PubMed1993

Simultaneous determination of glucose and 1-deoxyglucose in serum by anion-exchange chromatography with an immobilized pyranose oxidase reactor.

A liquid chromatographic system for the determination of glucose and 1-deoxyglucose in serum using an immobilized pyranose oxidase reactor and chemiluminescence detection is described. Separation was achieved on a TSK gel SAX column (2 cm x 4 mm I.D.) with an eluent of 0.1 M sodium hydroxide solution. Serum was diluted 30-fold with 0.1 M NaOH. Sample solution (50 microliters) was injected into the system. The hydrogen peroxide produced was detected by measuring the chemiluminescence emitted on admixing with luminol and potassium hexacyanoferrate (III). The calibration graphs were linear from 1 to 600 microM glucose and from 0.6 to 400 microM 1-deoxyglucose; the detection limits for glucose and 1-deoxyglucose were 0.5 and 0.3 microM, respectively. The sample throughput was 10/h. The immobilized enzyme reactor was stable for at least 2 months.

Anions↗

PubMed1989