The increasing demand for the production of polymers with prespecified properties has placed great emphasis on the development of accurate and robust instruments for the on-line monitoring of polym...

Recent Developments in Hardware Sensors For the On-Line Monitoring of Polymerization Reactions

Microgram quantities of technetium were determined by spectrophotometric procedure. Technetium was reacted with toluene-3,4-dithiol in acid medium and the complex extracted with carbon tetrachloride. The color intensity was measured at 450 m mu . Separation of technetium was required since many elements interfere. (auth)

Spectrophotometric Determination of Technetium with Toluene-3,4-dithiol

Utilizing the ion source and electrostatic analyzer of a double‐focusing mass spectrograph, the energy distribution of the ions formed by the pulsed rf vacuum spark has been determined for various materials and sparking conditions. Upon emerging from the electrostatic analyzer, the ion beam has a width, in the y direction, which is principally due to its angular divergence α and its energy spread β. By suitably reducing the widths of the defining slits, α can be made negligibly small. The beam width is then a nearly linear function of β alone, and a photoplate, placed just beyond the exit of the electrostatic analyzer, is used to determine the energy distribution of the ions produced in the source. A convenient energy scale is put on the same photoplate by exposing it to thermal ions (energy spread about 0.5 eV) which are accelerated to selected voltages while the deflecting voltage in the electrostatic analyzer is kept constant. In the present study, a 1×2 in. photoplate could be shifted by external means to permit 31 exposures to be made. Thus, many different sparking conditions and electrode materials, together with thermal ion calibrations, could be investigated and compared in a single experiment. At an accelerating voltage of 20 kV, an energy range of more than 3000 eV is recorded. The residual α, set by two 0.001‐in. defining slits, permits an energy resolution of 15 eV. The energy distribution of the ions produced by the rf spark depends strongly on the spark‐gap width, the rf voltage, and the electrode material. The narrowest energy spread possible is obtained with metallic electrodes at small rf voltages. So far, only two special cases were found where 90% of the ions were contained in an energy band no more than 500 eV wide. In all other instances, energy spreads are found to range from about 1000 to perhaps 5000 eV, with the mean energy located up to 1300 eV above the accelerating voltage. The fine structure and significance of these distributions is discussed in some detail.

Energy Distribution of Ions Formed in the rf Spark Source

A review and critical assessment is given of known evaluation methods of photographically recorded mass spectra (spark-source analysis of solids). The general calibration function of the complete analysis procedure serves as the embracing principle of order.

Assessment of quantitative evaluation methods of photographic spectra in mass-spectroscopic spark-source analysis

Determination of trace inpurities high-purity aluminum oxide by inductively-coupled plasma atomic emission-spectrometry

Gallium is separated from its impurities by solvent extraction of the HGaCl4 complex with isopropyl ether from 6-7 N HCl. Two extractions suffice to lower the Ga concentration to negligible amounts. The volume of the HCl phase after extraction is reduced and a measured portion dried on waxed graphite electrodes. The spectra are excited with a condensed spark and photographed. Maximum sensitivities reported are (parts impurity per million parts gallium). Al - .03, Ca - .03, Cr - .06, Cu - .015, Pb - .06, Mg - .015, Ni - .06, Zn - .12. The coefficient of variation of measurement varies from 3.6% for Cu to 14.8% for Pb.

The Spectrochemical Analysis of High Purity Gallium

This paper is a review presenting a description of the instrument and method, a brief summary of the early work, and a more detailed look at the development since 1960. Studies on the properties of photographic emulsions as ion detectors and the optimum conditions for their use are reported. Various methods are reported for quantitative data treatment, which include plate calibration, photometry, and corrections. Investigations of the spark source are reviewed, covering the causes and effects of the varying energy spectra and some corrections for the relative volatility and diffusion rates. The contribution of the sample itself to the analytical error is discussed, and the results obtained with rigorous standardization are presented.

Spark-Source Mass Spectroscopy

The sensitivity of Ilford Q2 photographic plates as detectors in mass spectrography has been investigated. The dependence of the sensitivity on the mass and energy of the impinging ions has been determined from the relative darkening of the emulsion produced by a fixed number of ions of mass 13 through 198 accelerated by voltages between 1.88 and 15 kv. The sensitivity was found to increase with increasing ion energy and to decrease with ion mass.

https://journals.sagepub.com/doi/pdf/10.1366/000370262774416191

The Effect of Ion Mass and Ion Energy on the Sensitivity of Ilford Q 2 Plates as Ion Detectors in Mass Spectrography

A method is described for the analysis of fused aluminum oxide and fused tin oxide crystals in which the treatment of the samples and standards removes the effects which sample form might have on spectral excitation The crystal sample is ground and then dissolved in a molten sodium carbonate-tetraborate flux The cooled cake is dissolved in dilute hydrochloric acid, and an internal standard is added A drop of the solution is dried on the flat end of a graphite electrode, and the spectra are excited with an ac arc The elements Cr, Co, Cu, Fe, Mn, Ni and V have been determined with the lower limits ranging from 0001 to 005% The method is applicable to many other elements over wide concentration ranges because of the convenient method of standardization

Edward B. Owens

Papers

The Spectrochemical Analysis of High Purity Gallium

Spark-Source Mass Spectroscopy

The Effect of Ion Mass and Ion Energy on the Sensitivity of Ilford Q 2 Plates as Ion Detectors in Mass Spectrography

Emission Spectrographic Analysis of Fused Aluminum Oxide and Fused Tin Oxide Crystals