摘要:

An analog-computer-DSC procedure has been outlined for determining the kinetic parameters EAand A for chemical reactions involved in the thermal decomposition of the amino acid, phenylalanine.

ISSN:0003-2719    

DOI:10.1080/00032717108058630

出版商:Taylor & Francis Group    

年代:1971

数据来源: Taylor

摘要:

A commercial acid concentration meter containing an N-type silicon anode and stainless cathode has been used to selectively measure hydrofluoric acid in mixtures containing nitric, phosphoric and sulfuric acids. At very high weight ratios of acid to HF (> 10:1) a suppression in HF response was noted for all acids examined. At lower ratios or higher HF values only nitric acid influences HF response with a sensitizing or catalytic effect not appreciably dependent on HNO, concentration.

ISSN:0003-2719    

DOI:10.1080/00032717108058631

出版商:Taylor & Francis Group    

年代:1971

数据来源: Taylor

摘要:

During sweep polarography in dimethylformamide (DMF) both Al (III) and Be (II) perchlorates produce well defined peaks which can be used for analytical purposes. The extent of solvolysis with time of the perchlorates in this medium was measured. In the presence of a complexing agent such as fluoride ions the rate of solvolysis is much lower and can be neglected. Therefore it is suitable to perform amperometric titration of Al(III) and Be (II) ions with fluoride.

ISSN:0003-2719    

DOI:10.1080/00032717108058632

出版商:Taylor & Francis Group    

年代:1971

数据来源: Taylor

摘要:

An analysis of the potentiometric titration curves for the silver-cyanide system indicates two possible approaches to the determination of cyanide ion at low levels. Both involve an indirect measurement of the silver ion in equilibrium with argentocyanide complex. These procedures are considerably more sensitive than the conventional method using a “silver iodide” cyanide responsive electrode.

ISSN:0003-2719    

DOI:10.1080/00032717108058633

出版商:Taylor & Francis Group    

年代:1971

数据来源: Taylor

摘要:

The polarography of copper(II) and copper(I) in acetonitrile-water mixtures, to which cysteamine or cystamine was added, has been studied. Copper(II) is rapidly reduced to copper(I) by cysteamine. Copper(I) forms several complexes with cystamine and cysteamine including Cu2(S-CH2-CH2-NH2).

ISSN:0003-2719    

DOI:10.1080/00032717108058634

出版商:Taylor & Francis Group    

年代:1971

数据来源: Taylor

摘要:

Tellurium has been determined at milligram and submilligram levels in the presence of uranium by a strictly instrumental photon activation121analysis procedure. The 575 keV gamma ray of Te was measured. At a decay time of three weeks, this gamma ray peak was interference-free. As little as 0.4 mg of tellurium was determined and the method evidences that sensitivity would increase with irradiation time.

ISSN:0003-2719    

DOI:10.1080/00032717108058635

出版商:Taylor & Francis Group    

年代:1971

数据来源: Taylor

摘要:

Neutron activation analysis was used for the determination of Na, Al, CI, K, Ca, Sc, Mn, Cu, Br, and La in the tobacco, mainstream smoke condensate, paper, and dropped ash of the Kentucky Reference Cigarette (IRI). The procedure requires no sample transfers prior to activation and no radiochemical separations before counting.

ISSN:0003-2719    

DOI:10.1080/00032717108058636

出版商:Taylor & Francis Group    

年代:1971

数据来源: Taylor

摘要:

Blank corrections in polarization measurements with single beam spectrofluorometers are straightforward and permit characterization of polarization spectra of samples having quantum yields of less than 0.01. Few samples require no such correction. Problems in determining what is a suitable blank are discussed. Such blanks have unfortunately been ignored in many studies, and dual phototube instruments have been advocated in which it is difficult to apply such corrections. G, the grating correction factor, is shown to vary sharply with emission wavelength, in contrast to other reports, but is independent of slit width. Therefore, a calibration curve of G vs. emission wavelength may be obtained for a given instrument, thus avoiding the need to determine G for each sample.

ISSN:0003-2719    

DOI:10.1080/00032717108058637

出版商:Taylor & Francis Group    

年代:1971

数据来源: Taylor

摘要:

An indirect method for the determination of OsO4, in the p.p.m. region is possible by measuring the decrease in fluorescence of the 4,6-bismethylthio-5-aminopyrimidine when OsO4, is added. At liquid N2temperatures 10 p.p.b. OsO4, can be detected. The OsO4, to ligand ratio was found to be 2:3. For 1 p.p.m. OsO4, 10 p.p.m. Ir+3, 1 p.p.m. Fe+3and less than 1 p.p.m. Ru+3and Pd+2can be tolerated. The fluorescent system is not affected by pH in the 3–12 ranges. It is suggested that the decrease in fluorescence results from a complexation reaction with the first site of reaction being the NH2. group. With increasing OsO4, concentration, oxidation appears to occur which produces a black product. This oxidation was not observed at p.p.b. concentrations of Os.

ISSN:0003-2719    

DOI:10.1080/00032717108058638

出版商:Taylor & Francis Group    

年代:1971

数据来源: Taylor

摘要:

A method for determining total hydrogen bonded to carbon has been developed, employing the 1st overtone of the C-H stretch which occurs in the near infrared spectral region. Six different hydrocarbons have been employed; all gave satisfactory results. Mixtures can be studied with an accuracy of approximately 10%. The method should find application in the study of pollution by organic materials.

ISSN:0003-2719    

DOI:10.1080/00032717108058639

出版商:Taylor & Francis Group    

年代:1971

数据来源: Taylor