摘要:

This paper recommends a simple and convenient procedure for the determination of copper(II) in the presence of large amounts of manganese. An aqueous solution of hydroxylamine hydrochloride and diluted sulphuric acid was used for dissolution and reduction of MnO2. The copper(II) was complexed with an ethanolic 0.05% PAN solution in the pH range of 2 - 3 in aqueous medium. The absorbances of copper-PAN complexes are measured at 550 nm where molar absorptivity is 2.10 L.mol−1.cm−1.

ISSN:0003-2719    

DOI:10.1080/00032718708064573

出版商:Taylor & Francis Group    

年代:1987

数据来源: Taylor

摘要:

When analyzing an insulating organic ponder the application of an external potential difference to the sample holder results in shifts of different Magnitudes for the XPS lines of the sample and that of the sample holder. The same effect is observed when the bias voltage is applied to a metallic substrate covered with a very thin polymer layer. This technique permits the separation of the sample signals from that of the sample holder or the substrate.

ISSN:0003-2719    

DOI:10.1080/00032718708064574

出版商:Taylor & Francis Group    

年代:1987

数据来源: Taylor

摘要:

A simple indirect atomic absorption spectrophotometric method is described for the determination of hydroxide ions. The method is based on the reduction of silver ions which takes place when hydroxide sample is treated with silver (I) solution in presence of manganese(II) ions. The unconsumed silver is determined by atomic absorption spectrophotometry. The effects of a number of factors have been studied and the method was employed for the determination of free alkali in paper samples.

ISSN:0003-2719    

DOI:10.1080/00032718708064575

出版商:Taylor & Francis Group    

年代:1987

数据来源: Taylor

摘要:

A simple, sensitive and alternative method for the spectrophotometric determination of iron(III) has been established. The procedure is based on the formation of iron-azide complexes in 60% (v/v) tetrahydrofuran/ water medium. The high sensitivity obtained in this method is due to the use of an interesting absorption band not previously reported in the literature. In the recommended conditions, absorbances for the ferric complexes are measured at 400 nm where the molar absorptivity is 1.52 × 1041 mol−1cm−1. The organic solvent used increases the sensitivity and the stability of the measurements. The precision is shown by the average deviation of about 0.3%. This system obeys Beer's law and is suitable for iron(III) determination in the concentration range from 0.6 to 3.2 mg 1−1(ppm). The best experimental conditions were determined studying the different factors involved. The influence of various diverse ions was also studied.

ISSN:0003-2719    

DOI:10.1080/00032718708064576

出版商:Taylor & Francis Group    

年代:1987

数据来源: Taylor

摘要:

An improved sparger unit, part of a commercially available purge and trap concentrator, has allowed for the determination of volatile organics in very “dirty” landfill leachates and septic samples. The loss of volatile organics is minimized during transfer steps by using the same glass tube for sample collection, for storage and for the analytical sparging operation. Chemometrics was used to compare the sparging efficiency of the original and the improved sparger unit.

ISSN:0003-2719    

DOI:10.1080/00032718708064577

出版商:Taylor & Francis Group    

年代:1987

数据来源: Taylor

摘要:

A new spectrophotometric procedure is described for the determination of ppm concentrations of adrenaline. The procedure is based on formation of Tris(O-phenanthroline)iron(II) complex (ferroin) upon reaction of adrenaline with an iron(III)-O-phenanthroline mixture in slightly acidic medium. The ferroin complex is then spectrophotometrically measured at 510 nm. In addition to being facile and rapid, the procedure is sufficiently selective and accurate, being particularly suitable for the assay of adrenaline in pharmaceutical formulations; the standard deviation didnot exceed 0.64%.

ISSN:0003-2719    

DOI:10.1080/00032718708064578

出版商:Taylor & Francis Group    

年代:1987

数据来源: Taylor

摘要:

A method using reversed-phase ion-pair high-performance liquid chromatography with electrochemical detection for the simultaneous determination of biogenic amines and metabolites has been developed. Two mobile phases one free of involatile substances have been compared for the separation of vanillylmandelic acid, 3,4-dihydroxy-phenylalanine, 3-methoxy-4-hydroxyphenylglycol, 3,4-dihydroxyphenylacetic acid, norepinephrine, 5-hydrozyindoleacetic acid, epinephrine, homovanillic acid, dopamine, serotonin, and 3-methoxytyramine. The present method can be applied to the analysis of brain, cerebrospinal fluid and plasma. Minimal sample preparation for brain and cerebrospinal fluid is required before injection into the liquid chromatograph. Molecular sieve chromatography and organic extraction is used for plasma cleanup for homovanillic acid determination. The procedure offers an attractive possibility for routine analysis of biogenic amines and their metabolites.

ISSN:0003-2719    

DOI:10.1080/00032718708064579

出版商:Taylor & Francis Group    

年代:1987

数据来源: Taylor

摘要:

The ability of flowers and blossoms to convert biochemical substrates into volatile products is utilized for the development of biosensors using such plant tissues as catalytic components. It is shown that both minced and intact tissue portions from carnation and chrysanthemum flowers can be coupled with potentiometric ammonia gas sensing electrodes to prepare sensors for urea and some amino acids with good response properties. Surprisingly different response and selectivity patterns are found among species of flowers and for the structural subelements of a single type of flower.

ISSN:0003-2719    

DOI:10.1080/00032718708064580

出版商:Taylor & Francis Group    

年代:1987

数据来源: Taylor

摘要:

A simple and sensitive spectrophotometric method for the determination of D-glutamate has been developed. The method is based on the racemization of D-glutamate with glutamate racemase (EC 5.1.1.3) and the simultaneous dehydrogenation of L-glutamate with L-glutamate dehydrogenase (EC 1.4.1.3). NADH produced was determined either by the measurement of absorbance at 340 nm or by the colorimetric measurement of a formazan formed at 515 nm. A linear relationship has been obtained between the absorbance and the amount of D-glutamate (0.01-0.2 μmol). Enantioselective determination was also possible by measuring L-glutamate with L-glutamate dehydrogenase before the addition of glutamate racemase.

ISSN:0003-2719    

DOI:10.1080/00032718708064581

出版商:Taylor & Francis Group    

年代:1987

数据来源: Taylor

摘要:

An HPLC method for the analysis of nitrofurantoin (NTR) in human urine has been developed and evaluated. This method is based on a selective extraction and reverse-phase chromatography which results in chromatograms with 2400 to 2500 theoretical plates for NTR and the internal standard (Furazolidone). The method is highly reproducible and has been validated over the range of 2 to 400 mcg/ml. A significant factor in the assay of nitrofurantoin, not common to most drugs, is that urine concentrations can exceed the aqueous solubility of the compound. Thus, special consideration in the handling of samples is needed to assure accuracy and reproducibility in the analysis. This method requires the pipetting of samples into precise aliquots prior to freezing and storage.

ISSN:0003-2719    

DOI:10.1080/00032718708064582

出版商:Taylor & Francis Group    

年代:1987

数据来源: Taylor