摘要:

A technique is presented for the determination of trace concentrations of copper (II) in natural water samples by cathodic stripping voltammetry of a film of copper-catechol complex ions adsorbed on the hanging mercury drop electrode. The peak height of the copper-catechol reduction peak is linearly dependent upon the copper (II) concentration between 10−10and 10−7M. The detection limit of the technique is below 10−10M copper (II) for a collection time of 3 minutes, but the sensitivity can be further increased four-fold by collecting for 15 minutes. The sensitivity is reduced by high concentrations of competing trace metals and of surfactants, which necessitate the use of standard additions to the sample.

ISSN:0003-2719    

DOI:10.1080/00032718408065362

出版商:Taylor & Francis Group    

年代:1984

数据来源: Taylor

摘要:

In 1 M ammonium nitrate supporting electrolyte, alternating current polarography of the α and β forms of molybdosilic acids yielded a single common peak. That peak provides a means for the determination of silicon in silicate solutions. The dynamic range of the method extends from 0.6 to 20 μg.mL−1of silicon.

ISSN:0003-2719    

DOI:10.1080/00032718408065363

出版商:Taylor & Francis Group    

年代:1984

数据来源: Taylor

摘要:

The adsorption of carbon monoxide and carbon dioxide on smooth Pt-Rh alloy has been studied by potentiodynamic technique. It is shown that the main products of CO and CO2adsorption on Pt-Rh alloys (15% Rh and below) are similar to products obtained on Pt electrodes.

ISSN:0003-2719    

DOI:10.1080/00032718408065364

出版商:Taylor & Francis Group    

年代:1984

数据来源: Taylor

摘要:

A polarographic procedure was developed which permits the analysis of powdered cupric and cuprous oxides in the presence of metallic copper. To determine CuO, Cu2O and metallic copper content in the sample two weight aliquots were used. The first aliquot was dissolved in medium of 50 % ethanol + 3 M hydrochloric acid + saturated ascorbic acid solution. Insoluable metallic copper was determined polarographically after its' separation and additional dissolving in concentrated nitric acid.

ISSN:0003-2719    

DOI:10.1080/00032718408065365

出版商:Taylor & Francis Group    

年代:1984

数据来源: Taylor

摘要:

Simplex optimization was used to optimize the temperature programmed gas chromatographic separation of octane, 2-methyltetrahydrofuran, butylcyclohexane, and ethylbenzene. The initial temperature and the programming rate were the factors studied and a 5 minute time constraint was placed on the system. The Chromatographic Response Function (CRF) used by Deming and Morgan1was used as an operational measure of performance. Further experiments in the region of the optimum and regression analysis of the data obtained were carried out to further understand the factor effects.

ISSN:0003-2719    

DOI:10.1080/00032718408065366

出版商:Taylor & Francis Group    

年代:1984

数据来源: Taylor

摘要:

A piezoelectric quartz crystal coated with tetrabutyphosphoniun chloride was found to be a good detector for acetoin. The coating is sensitive in the ppb range and completely reversible. The response curve is linear over a concentration range of 8-120 ppb. The detector can be tuned to give a satisfactory response in 30 seconds.

ISSN:0003-2719    

DOI:10.1080/00032718408065367

出版商:Taylor & Francis Group    

年代:1984

数据来源: Taylor

摘要:

The technique of sodium removal from acid solutions with Hydrated Antimony Pentoxide (HAP) has been used as a separation and preconcentration step in the determination of trace elements in many matrices. In trying to understand the mechanism of the sodium retention process the studies have revealed that although the retained sodium is difficult to elute, it can undergo an exchange process with dilute solutions of NaCl in hydrochloric acid. Hydrogen ions play a role in this exchange process.

ISSN:0003-2719    

DOI:10.1080/00032718408065368

出版商:Taylor & Francis Group    

年代:1984

数据来源: Taylor

摘要:

Increased use of instrumental analysis techniques is being required for critical quality control of polymeric raw materials used in the Thermal Protection System of Space Shuttl's External Fuel Tank. This paper is concerned with the FTIR evaluation of commercial room temperature vulcanized silicones. These silicone materials are two-component systems and the methodology developed is a comparison technique, and is performed via a computerized difference spectroscopy approach. A reference material is used as standard, and the subsequent lots are compared with the standard to assess their acceptability and conformance to specificatio. Results obtained so far indicated that the FTIR technique is a viable quality control procedure for use as a routine receiving/acceptance test.

ISSN:0003-2719    

DOI:10.1080/00032718408065369

出版商:Taylor & Francis Group    

年代:1984

数据来源: Taylor

摘要:

We describe in this paper a “pseudo-double beam” photoacoustic spectrometer using a wide aperture monochromator (F/2) and a very sensitive cell. The double signals required to get the normalized value, i.e., the sample signal and a carbon black reference signal, are obtained by a slow (1.7 Hz) alternating movement of the two cells support, the sample and the reference being alternately placed at the focus point of the beam which is fixed in space and time. The modulation of the light flux is independently ensured by a mechanical chopper. Such an original device associates good performances in resolution (0.7 nm), signal-to-noise ratio (1200 for HO2O3at 450 nm with a 5 nm bandwidth) and normalization in a wide spectral range.

ISSN:0003-2719    

DOI:10.1080/00032718408065370

出版商:Taylor & Francis Group    

年代:1984

数据来源: Taylor

摘要:

Multinuclear Fourier transform nmr spectroscopy is shown to be a potentially useful technique for the evaluation of commercial polysiloxanes. H,29Si: and13C nmr spectra are reported of the precursor solutions for RTV silicones. The13C show the increased presence of an unidentified material in unacceptable lots of one of the two precursor solutions.

ISSN:0003-2719    

DOI:10.1080/00032718408065371

出版商:Taylor & Francis Group    

年代:1984

数据来源: Taylor