Gold-platinum gauze

Debrak and Denoyer [484] determined mercury at the ppt level in seawater by the addition of tin chloride to produce hydrogen vapour, and trapping on gold-platinum gauze, prior to heating and detection of the mercury released by inductively coupled plasma mass spectrometry. 

Atomic Absorption Spectrometry. Today the most common method for the determination of total mercury in body fluids or tissues is atomic absorption spectrometry with the so-called cold vapor method (CV-AAS). Especially in combination with an amalgamation device (gold/platinum gauze), this method allows a direct determination of total mercury in blood or urine without any troublesome sample preparation prior to the analyses and in a concentration range relevant not only to occupational exposure but also to that required for general population studies [100]. For the general principles of this method, see Chapter 6 of this handbook. 

Debrah, E., Denoyer, E.R., and Tyson, J. E (1996). Flow injection determination of mercury with preconcentration by amalgamation on a gold-platinum gauze by inductively coupled plasma mass spectrometry.J. Ana/. At. Spectrom. 11(2), 127. 

Turyan and Mandler [483] determined ppt levels of mercury in seawater by first converting mercury salts to elemental mercury using stannous chloride, the mercury was then trapped on gold deposited on platinum gauze and released by heating prior to determination by inductively coupled plasma mass spectrometry. 

Recent developments in the ammonia oxidation process have included efforts to reduce catalyst losses in the process. Platinum recovery filters have been installed at various stages in the process. Gold/palladium gauze filter pads have been added on the exit side of the catalyst bed, inside the reactor/converter units. These filters have reportedly ensured a platinum recovery of 80% (Ref. PT4). Another trend has been for the use of additional filters in the downstream units. These filters are of alumino-silicate construction. 

Platinum family metals preparation. The platinum metals (with gold and silver) are commonly found together, and a number of schemes are in current use for their separation. Platinum metals not only are extracted from ores but, due to their high value, are also recovered from a wide range of industrial residues such as Pt, Rh gauze catalysts, defective components from glass industries, etc. 

Platinum, gold, and other noble metals (Pd, Rh, Ir). Platinum and gold are the most commonly used metallic solid electrodes. These metals are readily obtained in high purity, are easy to machine, and can be fabricated readily into a variety of geometric configurations—wires, rods, flat sheets, and woven gauzes. They are resistant to oxidation, but are not totally inert as often assumed in early work. 

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