Sample analysis and evaluation essay

Reasonable assumptions about mechanism of the stabilizing effect of Au and HCl on Hg measurements can be made. In this particular work, the carryover effects are of minimal concern because of the low absolute concentration of the Hg involved, and the need for extended flushing between samples to prevent organic or salt build up. It is believed that the major hindrance for Hg measurement in ICP-OES is the reduction of mercury in solution. For example, reported recovery of Hg in formalin becomes completely unreliable over time, more so than other reagent salts tested. This can be attributed to the reduction of Hg 2+ to Hg 0 in the formalin matrix. The inclusion of Au 3+ or HCl can therefore make the reduction of Hg 2+ unfavorable. Evidence for this can be explicitly shown by comparing the redox potentials of Hg in the presence of Au 3+ or HCl. The addition of gold (as AuCl 4 - ) can lead to competition between Hg 2+ and Au 3+ reduction reactions. Comparing the standard reduction potentials for mercury (equation 2) and gold (equation 3), we see that the Au 3+ reduction will be more favorable:

Sample analysis and evaluation essay

sample analysis and evaluation essay

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sample analysis and evaluation essaysample analysis and evaluation essaysample analysis and evaluation essaysample analysis and evaluation essay