摘要:

A Mini Review of recent advances in piezoelectric immunobiosensors is presented. First a review of the theory and history of the technique is given, followed by a critical survey of the use of this method in various fields of analysis.

ISSN:0003-2719    

DOI:10.1080/00032719908542975

出版商:Taylor & Francis Group    

年代:1999

数据来源: Taylor

摘要:

A cell based biosensor for phenolic substances has been developed. The set up is based on a flow injection system with an expanded bed column with immobilisedPseudomonascells. The cells were immobilised on glass particles pretreated with poly (ethylene diamine). The system responds to a range of phenolic substances. Storage and operational stabilities are good. The expanded bed concept makes the system reliable also when treating samples with particulate matter.

ISSN:0003-2719    

DOI:10.1080/00032719908542976

出版商:Taylor & Francis Group    

年代:1999

数据来源: Taylor

摘要:

The interactions of nile blue sulphate (NBS) with nucleic acids, including calf thymus DNA, fish sperm DNA and yeast RNA, were characterized with resonance light-scattering (RLS) measurements by using a common spectrofluorometer. Accordingly a method for the determination of nucleic acids at nanogram levels was established. At pH's of 7.20∼7.60 and ionic strengths lower than 0.012, the interactions of NBS with nucleic acids result in three characteristic RLS peaks at 293.4 nm, 349.4 nm and 560.4 nm. Mechanism study shows that these peaks are ascribed to the long range assembly of NBS on the molecular surface of nucleic acids, which depends on pH, ionic strength and the stranded structure of nucleic acids. A Scatchard plot was constructed by using the RLS data, yielding the assembly number and assembly constant being 6.4 and 7.13x106mol−11 for NBS assembly on the molecular surface of calf thymus DNA. The same parameters are 6.6 and 4.58x106mol−11 for the assembly on that of fish sperm DNA, 3.9 and 1.67x106mol−11 on that of yeast RNA, respectively. Linear relationships were found between the enhanced RLS intensity at 293.4 nm and nucleic acid concentration. If 1.2x10−5mol I−1NBS was employed, 0∼0.80 μg ml−1calf thymus DNA and fish sperm DNA, 0.20∼0.60 μg ml−1yeast RNA can be determined with the determination limits being 3.2 ng ml−1for calf thymus DNA, 11.5 ng ml−1for fish sperm DNA and 38.3 ng ml−1for yeast RNA, respectively. Four synthetic samples were determined with satisfaction.

ISSN:0003-2719    

DOI:10.1080/00032719908542977

出版商:Taylor & Francis Group    

年代:1999

数据来源: Taylor

摘要:

The fluorescence quenching of the Tb-BPMPHD-CTMAB by nucleic acids is reported. The maximum fluorescence quenching was obtained at pH5.5, with maximum excitation and emission wavelengths at 300 and 543nm, respectively. Under optimal conditions, the differential value of fluorescence intensity between the absence and presence of nucleic acids was proportional to the concentration of nucleic acids over the range of 4.0x10−8∼ 1.0x10−5g/ml for fsDNA and 2.5x10−8∼ 6.15x10−6g/ml for yRNA, respectively. The corresponding detection limits are 9.0ng/ml for fsDNA and 5.0ng/ml for yRNA. The method was applied to the determination of DNA (or RNA) in synthetic samples. The results obtained were satisfactory.

ISSN:0003-2719    

DOI:10.1080/00032719908542978

出版商:Taylor & Francis Group    

年代:1999

数据来源: Taylor

摘要:

A method for protein determination using eosin Y is described. Eosin Y reacts with proteins under acidic conditions and forms an intense pink proteineosin Y complex with an absorbance maximum of 535-545nm. The color produced from this reaction is stable and its absorbance increases proportionally over a wide range of protein concentrations (standard assay, 50-1000μg/ml of BSA; microassay, 1.25-50μg/ml of BSA). The eosin Y method can be performed at room temperature without further incubation after vortex mixing. The assay has advantages such as (i) simple procedures, (ii) stable dye-protein color with no precipitation of dye-protein complex for at least 72h, (iii) good reproducibility and (iv) rapid reaction. The characterization of the eosin Y method extends its best application to a routine protein determination in solution.

ISSN:0003-2719    

DOI:10.1080/00032719908542979

出版商:Taylor & Francis Group    

年代:1999

数据来源: Taylor

摘要:

A rapid and simple method for monitoring the growth ofThiobacillus ferrooxidansis put forward by using a series piezoelectric quartz crystal (SPQC). The SPQC was applied to continuously determine the variation of frequency shift during the culture ofThiobacillus ferrooxidans, with a conductive electrode as the probe. The frequency shift as a function of time agrees with a typical 'S - shape' model, a piezoelectric sensor responding well to the growth ofThiobacillus ferrooxidans. The fundamentals for determination of the bacterial growth activity using the SPQC is also described; the frequency shift is only dependent on the electrical conductivity of the solution and the dielectric constant.

ISSN:0003-2719    

DOI:10.1080/00032719908542980

出版商:Taylor & Francis Group    

年代:1999

数据来源: Taylor

摘要:

A micellar electrokinetic chromatographic method which permits the separation of very similar compounds such as ethinylestradiol (ETE), gestodene (GTD), (-)norgestrel (LEV) and β-estradiol valerate (EST) from synthetic mixtures is described. The study was carried out at 25°C and 20 kV, using a 15 mM borate buffer (pH 9.2), 15 mM sodium dodecylsulfate (SDS) and 26% acetonitrile-water as background electrolyte. The analysis takes about 12 minutes.

ISSN:0003-2719    

DOI:10.1080/00032719908542981

出版商:Taylor & Francis Group    

年代:1999

数据来源: Taylor

摘要:

A careful study of the parameters affecting the chemiluminescent reaction of TCPO (bis(2,4,6-trichlorophenyl)oxalate) and 2-NPO (bis(2-nitrophenyl)oxalate) with hydrogen peroxide, in the presence of imidazole (used as buffer and catalyst) and the fluorophore 3-AFA (3-aminofluoranthene), was carried out in acetonitrile/water medium. The data are reported in terms of the time (tImax) required for the relative maximum chemiluminescence intensity (Imax) and the area (A) under the curve of intensity νs. time. At controlled acidity and high unprotonated imidazole concentration ([IMI] = 1x10−2mol.L−1), the Imaxand tImaxvalues do not depend on the acetonitrile/water ratio. The CL intensity is maximum at around pH 6.0 (higher buffer capacity). For 1x10−2< [IMI] < 1x10−4mol.L−1, the area is largest when [IMI] = 1x10−3mol.L−1and linearly dependent on the hydrogen peroxide concentration (10−5− 10−3mol.L−1). The area is also enhanced by increasing the fluorophore concentration. The acidity controls the unprotonated imidazole and H+concentration. Several errors can arise from quantitative analyses carried out without control of the HIMI+and IMI concentrations.

ISSN:0003-2719    

DOI:10.1080/00032719908542982

出版商:Taylor & Francis Group    

年代:1999

数据来源: Taylor

摘要:

This paper shows the benefits of optimizing the wavelength range and number of factors used in the simultaneous spectrophotometric determination of several analytes in the same sample by use of partial least-squares regression. The optimization criterion used for this purpose is based on the relative standard error of prediction (RSEP), which represents the overall error for a series of mixtures containing different amounts of the analytes; the optimum wavelength range and number of factors are chosen to be those leading to the lowest RSEP value. The ensuing method was applied to the simultaneous determination of the diuretics spironolactone and althiazide at concentrations between 2 and 20 μg · mL−1in synthetic samples, where the drugs were quantified with errors less than 5% (spironolactone) and 2.5% (althiazide), and relative standard deviations below 3.5 and 0.8%, respectively. Both drugs were also determined in a pharmaceutical preparation, with recoveries of 100.76% (spironolactone) and 95.86% (althiazide) relative to their nominal contents, and relative standard deviations of 1.1 and 3.5%, respectively. The proposed method for the analysis of the pharmaceutical preparation was validated by HPLC.

ISSN:0003-2719    

DOI:10.1080/00032719908542983

出版商:Taylor & Francis Group    

年代:1999

数据来源: Taylor

摘要:

A novel algorithm of wavelet transform, called the on-line wavelet transform, which can be used in on-line processing of signals of an instrumental analysis, is proposed. And application of the on-line wavelet transform in denoising of high performance liquid chromatograms was investigated. Results showed that the noise in chromatograms was cleanly removed by the method, peak position after the on-line de-noising dose not change, and the linearity of calibration curves of concentration versus peak area remained and even was improved. Quantitative determination of three mixed samples were investigated with five standard samples; the recoveries were between 94.0-105.0%.

ISSN:0003-2719    

DOI:10.1080/00032719908542984

出版商:Taylor & Francis Group    

年代:1999

数据来源: Taylor