摘要:

An amperometric biosensor for the determination of phenols is proposed using a crude extract of sweet potato(Ipomoea batatas (L.) Lam.)as an enzymatic source ofpolyphenol oxidase(PPO;tyrosinase; catechol oxidase; EC 1.14.18.1). The biosensor is constructed by the immobilization of sweet potato crude extract with glutaraldehyde and bovine serum albumin onto an oxygen membrane. This biosensor provides a linear response for catechol, pyrogallol, phenol and p-cresol in the concentration ranges of 2.0×10−5-4.3×10−4mol L−1, 2.0×10−5-4.3×10−4mol L−1, 2.0×10−5-4.5×10−4mol L−1and 2.0×10−5-4.5×10−4mol L−1, respectively. The response time was about 3–5 min for the useful response range, and the lifetime of this electrode was excellent for fifteen days (over 220 determinations for each enzymatic membrane). Application of this biosensor for the determination of phenols in industrial wastewaters is presented.

ISSN:0003-2719    

DOI:10.1080/00032719708002304

出版商:Taylor & Francis Group    

年代:1997

数据来源: Taylor

摘要:

Determination of donor identity and commonality of origin among paraffin embedded tissues and slides becomes important when criminal or civil action is taking place. Determining the identity of the specimens' donor can be facilitated by forensic DNA identity testing. Previous work has shown that PCR based identity testing is feasible on fixed, paraffin-embedded tissues and slides. The use of differential staining and other contrast enhancing procedures may alter the ability to recover template DNA for PCR based identity testing. Using sections on slides that had been treated with a variety of different stains/immuno-probes (Hematoxylin and Eosin, Gridely's Silver Method for Reticulum, Grocott's Methenamine Silver, immunofluorescent staining,IN-SITUhybridization, etc.) the ability to perform PCR based identity testing was evaluated. Samples were also subjected to a destaining procedure to remove stains that potentially could interfere with the DNA extraction or PCR process. Destaining was found to improve the ability to amplify some stained specimens. Samples were subjected to ChelexRextraction for template preparation. The process utilized and its advantages are discussed.

ISSN:0003-2719    

DOI:10.1080/00032719708002305

出版商:Taylor & Francis Group    

年代:1997

数据来源: Taylor

摘要:

The composition and the stability constant of the Al(III)-hesperidin complex were determined by suitable spectrophotometric methods and pH measurements. The formation of the complex, whose concentration stability constant log K1ranged from 3.46 at pH=4.0 to 4.54 at pH=5.0, was established. The conditions for the spectrophotometric determination of hesperidin, by means of the complex formation, were investigated. It was found that hesperidin can be determined in the range from 2.50×10−5M to 1.75×10−4M. The application to the determination of hesperidin in orange juice is demonstrated. All investigations were carried out with 70% methanolic solutions at room temperature (20°C), constant values of pH (3.7), and ionic strength (0.01).

ISSN:0003-2719    

DOI:10.1080/00032719708002306

出版商:Taylor & Francis Group    

年代:1997

数据来源: Taylor

摘要:

The simultaneous determination of the active ingredients in a multicomponent pharmaceutical product is reported. Pseudoephedrine HCl (I), guaifenesin (II) and dextromethorphan HBr (III) were separated and quantitated simultaneously in a cough syrup by HPLC using an isocratic, reverse-phase system. The column consisted of a octadecylsilane 5-micron stationary phase. The mobile phase was 45% (v/v) aqueous methanol with ammonium formate as buffer (pH 4.3). The retention times were approximately 4.50, 7.30 and 17.60 minutes for (I), (II) and (III), respectively. The method is repeatable and reproducible.

ISSN:0003-2719    

DOI:10.1080/00032719708002307

出版商:Taylor & Francis Group    

年代:1997

数据来源: Taylor

摘要:

The fluorescence enhancement of the Eu-dibenzoylmethane(DBM)- cetylpyridinium-chloride (CPC) system was studied. The fluorescence intensity of the system can be greatly increased by Gd3+in the presence of triethanolamine(TEA). The optimum conditions for enhanced fluorescence of the Eu-Gd-DBM-CPC system were examined. It was a linear function of the Eu3+concentration in the range of 1.0×10−10∼1.0×10−8mol dm−3under the optimized conditions. The detection limit was 2.6 × 1011mol dm−3in an aqueous solution at pH=7.5∼9.5.

ISSN:0003-2719    

DOI:10.1080/00032719708002308

出版商:Taylor & Francis Group    

年代:1997

数据来源: Taylor

摘要:

From the color developing reactions of various phenylenediamine derivatives (I)-(V), oxidizing agent and gold(III). the combination ofN,N-dimethyl-p-phenylenediamine (DPD)(II) and potassium persulfate in acidic media was used for a simple and sensitive spectrophotometric determination of gold(III). The calibration graph was linear in the range of 0–300 ng/10 ml gold(III) with a molar absorptivity of 1.9 × 106l mol−1cm−1at 552 nm. The proposed method had higher sensitivity than other spectrophotometric methods, and was applied to the assay of gold(III) in gold-pharmaceuticals such as sodium aurothimaleate and auranofin. The results were satisfactory.

ISSN:0003-2719    

DOI:10.1080/00032719708002309

出版商:Taylor & Francis Group    

年代:1997

数据来源: Taylor

摘要:

In the present communication a simple and rapid spectrophotometric method for the determination of titanium is described. The method is based on the reaction of Ti(IV) with a newly synthesized reagent, 6-(4-nitrophenylazo)-3,4,5-trihydroxy benzoic acid (NATHB), in ethanol medium at pH 3.2 to 4.2. The complex exhibits an absorption maximum at 495 nm and Beer's law is valid over the range of 0.04 – 1.00 μg.ml−1Ti. The molar absorptivity is 3.48 × 104dm3.mole−1. cm−1. Most of the foreign metal ions and anions do not produce any colorations with NATHB at selected conditions. Based on these results, a simple and direct spectrophotometric method with high selectivity and sensitivity was proposed. The method has been successfully applied for the determination of titanium in 5 soil and 3 standard geochemical samples.

ISSN:0003-2719    

DOI:10.1080/00032719708002310

出版商:Taylor & Francis Group    

年代:1997

数据来源: Taylor

摘要:

A catalytic-kinetic method for the determination of selenium is proposed. Brilliant cresyl blue is reduced by sodium sulphide to form a colourless product. The reaction is accelerated by ultra trace amounts of Se(IV), and can be followed by measuring the decrease in absorbance of the dye at 630 nm and 30°C. selenium can be determined in the range of 0.0001 – 0.500 μg.ml−1with a limit of detection of 3 × 10−5μg.ml−1. The relative standard deviations are 2.5, 2.2 and 2.0% for 0.10. 10.0, and 100.0 ng.ml−1of Se(IV), respectively. This method was successfully applied to the determination of selenium in waste water.

ISSN:0003-2719    

DOI:10.1080/00032719708002311

出版商:Taylor & Francis Group    

年代:1997

数据来源: Taylor

摘要:

Exposure of BPDE-DNA adducts adsorbed on two different types of filter paper to ultraviolet radiation for 60 minutes showed that the solid-matrix fluorescence of the adducts changed very little with time for the adducts adsorbed on Whatman 1PS filter paper. This indicated that tetrols which could be formed from the adducts were not readily produced under these conditions. Synchronous scanning solid-matrix phosphorescence was investigated for the detection of tetrols in the presence of BPDE-DNA adducts adsorbed on 1PS filter paper. The results showed that tetrol could be detected at sub-nanogram levels with the adducts adsorbed on the filter paper.

ISSN:0003-2719    

DOI:10.1080/00032719708002312

出版商:Taylor & Francis Group    

年代:1997

数据来源: Taylor

摘要:

A method is presented for trace-element analysis of lead and zinc by potentiometric stripping analysis (PSA) where both the glassy-carbon working electrode and the electrolyte are free of mercury. Analysis of zinc requires an activation of the glassy-carbon electrode. The activation is performed by pre-concentrating zinc on glassy carbon at −1400 mV(SCE) in a mercury-free electrolyte containing 0.1 M HCl and 2 ppm Zn2+, followed by stripping at approx. −1050 mV. A linear relationship between stripping peak areas, recorded in the derivative mode, and concentration was found in the range 0–2000 ppb.

ISSN:0003-2719    

DOI:10.1080/00032719708002313

出版商:Taylor & Francis Group    

年代:1997

数据来源: Taylor