The Gold Plating of Graphite for the Determination of Mercury with Flameless Devices

Flameless atomizers for atomic absorption have greatly extended the sensitivities of atomic absorption measurements for a great many elements. When determining elements in solutions, one generally pipets a small volume into the graphite cups or tubes of the flameless device and dries the solution in the graphite prior to atomization. Mercury determinations by these methods, however, are a greater problem because of the high volatility of mercury and many of its compounds. Very often analysts experience great difficulty in obtaining working curves for mercury when using flameless devices. Standard deviations are often quite large, leaving one with a great deal of uncertainty in the results obtained. We have recently discovered that by plating the inner surface of graphite tubes and cups with a thin layer of gold these problems can be eliminated.