Platinum determination

Phototubes, multiplier, 56-59, 222 Placement error, 285-287 Planck s constant, 7, 8 Plastics, characterization by absorptiometry, 78, 79 Plateau, characteristic, 60 Platinum, determination by x-ray emission spectrography, 161, 328 L peaks, measured by Bragg, 25, 26, 35 L spectra, 35... 

In addition, selected rare elements, such as precious metals, were extracted from matrix elements and preconcentrated to avoid isobaric interferences with polyatomic ions as demonstrated for platinum determination in the presence of a relatively high concentration of Hf, resulting in isobaric interferences at m/z = 194, 195 and 196 due to HfO+ diatomic ion formation.17 An improved method for extracting marine sediment fractions and its application for Sr and Nd isotopic analysis is described by Bayon et al.ls... 

S. Lustig, S. Zang, B. Michalke, P. Schramel, W. Beck, Platinum determination in nutrient plants by inductively coupled plasma mass spectrometry with special respect to the hafnium oxide interference, Fresenius J. Anal. Chem., 357 (1997), 1157D1163. 

Bosch, O.C., Sanchez, R.F., Cano, P.J., Garcia de Torres, A. Automated on-line separation-preconcentration system for platinum determination by electrothermal atomic absorption spectrometry. Anal. Chlm. Acta 494, 97-103 (2003)... 

Alfassi, Z.B., Probst, T.U., Rietz, B. Platinum determination by instrumental neutron activation analysis with special reference to the spectral interference of scandium-47 on the platinum indicator nuclide gold-199. Anal. Qiim. Acta 360, 243-252 (1998)... 

Giaveri, G., Rizzio, E., Gallorini, M. Preconcentration and preseparation procedure for platinum determination at trace levels by neutron activation analysis. Anal. Chem. 73, 3488-3491 (2001)... 

Nicked circular PM2 DNA (0.02 mg/mL) was incubated in NaClOt (10 mM) with platinum compounds at 20 C in the dark for 8 d. After dialysis against NaClOt (10 mM) and platinum determination by atomic absorption spectrophotometry, the complexes were absorbed on carbon-coated copper grids and observed using a Philips 301 electron microscope. The average length of control DNA (Ldsa) and of platinum-DNA complexes (Ldna pO were determined from an observation of at least 60 molecules. 

Spatial Resolution or Unsharpness The total resolution of the system is to be established via a platinum duplex wire penetrameter according to EN 462-5. The resolution limit that has been determined by this IQI can be directly converted to the system unsharpness. 

Ruch and Bartell [84], studying the aqueous decylamine-platinum system, combined direct estimates of the adsorption at the platinum-solution interface with contact angle data and the Young equation to determine a solid-vapor interfacial energy change of up to 40 ergs/cm due to decylamine adsorption. Healy (85) discusses an adsorption model for the contact angle in surfactant solutions and these aspects are discussed further in Ref. 86. 

If an appreciable amount of residue remains, note its colour. Add a few drops of water and test the solution (or suspension) with htmus or with Universal indicator paper. Then add a httle dilute hydrochloric acid and observe whether efiervesceiice occurs and the residue dissolves. Apply a flame test with a platinum wire on the hydrochloric acid solution to determine the metal present. (In rare cases, it may be necessary to subject a solution of the residue to the methods of qualitative inorganic analysis to identify the metal or metals present.) If the flame test indicates sodium, repeat the ignition of the substance on platinum foil. 

Procedures for determining the quaUty of formaldehyde solutions ate outlined by ASTM (120). Analytical methods relevant to Table 5 foUow formaldehyde by the sodium sulfite method (D2194) methanol by specific gravity (D2380) acidity as formic acid by titration with sodium hydroxide (D2379) iron by colorimetry (D2087) and color (APHA) by comparison to platinum—cobalt color standards (D1209). 

Apparent equivalent weight deterrnined by titration with hydrochloric acid. APHA color determined by ASTM D1209, platinum—cobalt method. 

The best indirect, but seldom used, method is to determine the total moisture separately in a Penfteld tube, determine the loss on ignition in air at 825—875°C, and report graphitic carbon as percent loss on ignition (100 — %moisture — %ash). It is desirable to use a platinum dish for ignition loss and it... 

Thermal Properties. The thermal stabiUty of cellulose esters is deterrnined by heating a known amount of ester in a test tube at a specific temperature a specified length of time, after which the sample is dissolved in a given amount of solvent and its intrinsic viscosity and solution color are deterrnined. Solution color is deterrnined spectroscopically and is compared to platinum—cobalt standards. Differential thermal analysis (dta) has also been reported as a method for determining the relative heat stabiUty of cellulose esters (127). 

In biological materials, various nonspecific precipitants have been used in the gravimetric deterrnination of choline, including potassium triiodide, platinum chloride, gold chloride, and phosphotungstic acid (28). Choline may also be determined spectrophotometricaHy and by microbiological, enzymatic, and physiological assay methods. 

The bot-wire anemometer consists essentially of an electrically heated fine wire (generally platinum) exposed to the gas stream whose velocity is being measured. An increase in fluid velocity, other things being equal, increases the rate of heat flow from the wire to the gas, thereby tending to cool the wire and alter its electrical resistance. In a constant-current anemometer, gas velocity is determined by measuring the resulting wire resistance in the constant-resistance type, gas velocity is determined from the current required to maintain the wire temperature, and thus the resistance, constant. The difference in the two types is primarily in the electric circmts and instruments employed. 

Significant distinction in rate constants of MDASA and TPASA oxidation reactions by periodate ions at the presence of individual catalysts allow to use them for differential determination of platinum metals in complex mixtures. The range of concentration rations iridium (IV) rhodium (III) is determined where sinergetic effect of concentration of one catalyst on the rate of oxidation MDASA and TPASA by periodate ions at the presence of another is not observed. Optimal conditions of iridium (IV) and rhodium (III) determination are established at theirs simultaneous presence. Indicative oxidation reactions of MDASA and TPASA are applied to differential determination of iridium (IV) and rhodium (III) in artificial mixtures and a complex industrial sample by the method of the proportional equations. 

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