摘要:

An amperometric procedure for the measurement of magnesium(II) has been developed using the enzyme hexokinase in solution and glucose oxidase immobilized onto a preactivated polymeric support. The reaction of hexokinase was monitored following the decrease in current due to the glucose consumption by the enzyme in the presence of the ATP-Mg2+complex. The reaction rate was dependent on the concentration of magnesium(II) in solution. Concentrations of hexokinase and ATP were optimised. Measuring the current change in the 1-3 min interval after the start of the reaction magnesium(II) can be determined in the 4 × 10−5to 10−3M range. Other divalent cations tested showed no interference. The magnesium(II) content of 5 pharmaceutical products was measured with the amperometric and compared to a spectrophotometric procedure. The results correlated well.

ISSN:0003-2719    

DOI:10.1080/00032719608000417

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor

摘要:

A solid surface room temperature phosphorescence optosensing method has been developed for the determination of terbium(III) based on the adsorption of its binary complex with 1,4-bis (l'-phenyl-3′-methyl-5′-pyrazolone-4′-) butanedione-(1,4) (BPMPBD) onto the hydrogen form of a strong cation exchange resin packed in a flow cell in an aqueous flow system. The phosphorescence intensity is a linear function of the concentration of terbium in the range of 8x10−9M-6x10−7M, and the detection limit is 3x10−9M terbium. The response mechanism was also studied. The present optosensor has been used for the determination of trace amounts of terbium in synthetic samples with satisfactory results.

ISSN:0003-2719    

DOI:10.1080/00032719608000418

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor

摘要:

The use of iodinated Bolton-Hunter reagent (IBHR) - labelled avidin and of IBHR-labelled biotin in immunoassays for the measurement of human IgG is investigated. The IBHR label is detected using the reaction between cerium(IV) and antimony(III). The results are compared to those obtained for immunoassays using IBHR-labelled antibodies or enzyme-labelled antibodies.

ISSN:0003-2719    

DOI:10.1080/00032719608000419

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor

摘要:

The hydroxyl groups carrying supports, Sepharose Cl-4B and Fractogel HW75F, were facilely activated under anhydrous conditions using bis(4-nitrophenyl) carbonate (BPNPC), a stable and readily available compound. The activation time at room temperature can be as short as 0.5 hour. The activated supports can be stored at 4°C for at least one month without any loss of coupling capacity. Amines can be coupled to the activated support at pH 7 to 10. Coupling of Protein A to BPNPC activated supports yielded immobilized Protein A affinity supports having a high IgG binding capacity. For example, the Protein A-Sepharose and Protein A-Fractogel prepared by using the BPNPC activation method were able to bind, respectively 13 - 14 mg and 8 - 9 mg human IgG with phosphate buffer saline as the loading buffer. In contrast the use of a high yield binding buffer increases the binding capacity of the two affinity supports to 25 - 28 mg and 22 mg respectively.

ISSN:0003-2719    

DOI:10.1080/00032719608000420

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor

摘要:

A polarographic enzyme-immunoassay for Hepatitis B Surface Antigen(HBsAg) has been established, in which horseradish peroxidase(HRP) is used as the labeled enzyme, o-phenylenediamine(OPD) as the substrate, and the enzyme-generated product,2,2′-diaminoazobenzene (DAA). is detected by linear-potential scan polarography. Under optimal conditions, the second derivative current of DAA is linear with the concentration of HBsAg from 0.1 to 5 ng/mL. The correlation coefficient(r) is 0.9994. The detection limit is 0.05ng/mL and the relative standard deviation is 6.7%(8 replicates). The sensitivity of the assay is about 20-fold higher than that of ELISA. The assay has been successfully applied for minute determination of HBsAg in both human serum and the negative control serum from ELISA kits.

ISSN:0003-2719    

DOI:10.1080/00032719608000421

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor

摘要:

The research on the reaction of the metal complex (BPR-Zn2+) as spectrum probe for protein in alkaline medium was conducted in this paper. The experiments indicate that the ternary complex between BPR-Zn2+complex and protein could be used as a method for protein determination. The reaction conditions, interference materials and sample were studied. A dual-wavelength method is applied to obtain the binding number of spectroscopic probe bound on molecular protein and the reaction mechanism was studied.

ISSN:0003-2719    

DOI:10.1080/00032719608000422

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor

摘要:

The hemoglobin concentration in diluted whole blood has been amperometrically measured using a toluidine blue O covalently modified microcylinder carbon fiber electrode. The modified electrode was prepared by modifying the surface of carbon fiber by cyclic voltammetric oxidation to form a lot of -COOH groups, and then covalently linking toluidine blue O (TBO) by acylation. The surface morphology and stability of the TBO modified electrode are discussed. The electrochemical behaviour of the modified electrode was studied by cyclic voltammetry. The number of H+participating in the surface electrode process and some kinetic parameters in various pH solutions were determined. The TBO modified microelectrode showed significant electrocatalytic activity for the oxidation of hemoglobin(HB) in pH 5.4 solution. The amperometric response to HB increased linearly with increasing concentration from 8.0x10−6to 8.0x10−4M. The obtained HB concentration correlated well with that obtained using a reference procedure.

ISSN:0003-2719    

DOI:10.1080/00032719608000423

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor

摘要:

Metallothionein-II (MT-II) and Cu, Zn-superoxide dismutase (Cu, Zn-SOD) interacted with mercury were detected by a new method utilizing isoelectric focusing-agarose or -polyacrylamide gel electrophoresis (IEF-AGE or IEF-PAGE) and nondestructive one-dimensional synchrotron radiation X-ray fluorescence (SR-XRF) analysis. When MT-II reacted with mercuric chloride, an obvious change of isoelectric point (pI = 3.7 - 4.7) for the intact form to alkaline pI (9.4) was observed. This marked migration of MT-II by the metal was blocked by addition of glutathione, suggesting that sulfhydryl functions participate in the pI variation. In contrast, interaction of Cu, Zn-SOD with mercury did not cause any changes of its pI although the metal bound tightly to Cu, Zn-SOD after electrophoresis; however, the enzyme activity was drastically suppressed. These observations indicate that combination of electrophoresis with SR-XRF analysis is an useful technique for detecting structural or functional alteration of protein attributable to the binding of the mercury.

ISSN:0003-2719    

DOI:10.1080/00032719608000424

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor

摘要:

Waste waters polluted with toxic metals can be successfully purified by precipitation of the metals from an alkalinised solution containing iron(II) as ferrite sludge with magnetic properties. The magnetic ferrites obtained by this treatment can be disposed or reutilised with smaller risk for the environment since metals contained in the ferrite are less available. A Taguchi experimental design has been applied to the optimisation of the ferrite precipitation process, the aim being to achieve the maximum purification of the solution and the best magnetic characteristics of the ferrite. Four control factors at three levels were explored. (Fe(II) concentration)/(total metal concentration) ratio, temperature, treatment duration and pH, and assigned to the columns of a L9(34) orthogonal array. A noise factor (potassium permanganate) at three concentration levels was also introduced to simulate the uncontrollable variability of the waste water composition. Optimal heavy metal removal (>99%) and magnetic susceptibility of the ferrite were attained when waste water samples where treated for 2 hours at 50 °C and pH 10 in the presence of iron(II) sulphate in a ratio [Fe(II)] / [total metal] of 15. Ferrites obtained by the optimised procedure have been characterised by X-Ray Diffractometry and X-Ray Fluorescence Spectroscopy, confirming that the solid has a magnetite structure and contains all the metals initially in solution.

ISSN:0003-2719    

DOI:10.1080/00032719608000425

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor

摘要:

A method has been established for enrichment of trace amounts of copper in aqueous solutions on an activated carbon column. Copper was quantitatively retained on a chromatographic column packed with activated carbon, after complexation with 1-nitroso-2-naphthol or hexamethylene dithiocarbamate and elution with 2 M HCl in acetone. The developed method was used for the determination of trace amounts of copper in water samples with good results. (Recoveries between 95-101%, relative standard deviations 3-5%)

ISSN:0003-2719    

DOI:10.1080/00032719608000426

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor