Gold determination

L13. Lorber, A., Cohen, R. L., Chang, C. C., and Anderson, H. E., Gold determination in biological fluids by atomic absorption spectrophotometry application to chrysotherapy in rheumatoid arthritis patients. Arthritia Rheum. II, 170-177... 

P. Di and D. E. Davey, Trace gold determination by online preconcentration with flow injection atomic absorption spectrometry, Talanta, 41(4), 1994, 565-571. 

Bristowe, P. D., Sass, S. L. (1980). The atomic structure of a large angle (001) twist boundary in gold determined by a joint computer modelling and x-ray diffraction study. Acta Metall., 28, 575-88. 

Trace gold determination by on-line preconcentration with flow injection atomic absorption spectrometry, by use of di(methylheptyl)methyl phosphonate (DMHMP) as the immobilized phase loaded onto a macroporous resin Radiochemical separation and determination of gold complex matrices employing substoichiometric thermal neutron activation analysis... 

A resistor is colour coded blue, grey, green, gold. Determine the value of the resistor. 

Figure 5.8 shows a plot of the logarithm (to the base 10) of the diffusion eoeffident versus reciprocal of absolute temperature for the diffusion of eopper in gold. Determine valnes for the activation energy and the preexponential. 

The development of scanning probe microscopies and x-ray reflectivity (see Chapter VIII) has allowed molecular-level characterization of the structure of the electrode surface after electrochemical reactions [145]. In particular, the important role of adsorbates in determining the state of an electrode surface is illustrated by scanning tunneling microscopic (STM) images of gold (III) surfaces in the presence and absence of chloride ions [153]. Electrodeposition of one metal on another can also be measured via x-ray diffraction [154]. 

Harder P, Grunze M, Dahint R, Whitesides G M and Laibinis P E 1998 Molecular conformation in oligo(ethylene glycol)-terminated self-assembled monolayers on gold and silver surfaces determines their ability to resist protein adsorption J. Rhys. Chem. B 102 426-36... 

Titrimetric Methods. Frequently, the reduction of gold solutions leads to finely divided precipitates which are difficult to recover quantitatively. In such cases, the reduction of Au(III) to Au(0) by, eg, hydroquinone, can be followed potentiometricaHy (49). The end point in such titrations also can be determined with indicators such as benzidine (50) or o-anisidine (51). Alternatively, the reduction can be effected with excess hydroquinone which is then back-titrated with Ce(IV) (52). lodometric deterrnination of Au(III) also is useflil (53). 

Determination of gold concentrations to ca 1 ppm in solution via atomic absorption spectrophotometry (62) has become an increasingly popular technique because it is available in most modem analytical laboratories and because it obviates extensive sample preparation. A more sensitive method for gold analysis is neutron activation, which permits accurate determination to levels < 1 ppb (63). The sensitivity arises from the high neutron-capture cross section (9.9 x 10 = 99 barns) of the only natural isotope, Au. The resulting isotope, Au, decays by P and y emission with a half-life of 2.7 d. 

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