Patent ID: 8685172

Claim:
A method for processing a sample, the method comprising: (a) providing a sample processing apparatus, the sample processing apparatus comprising: a pressure chamber having an interior volume constructed to receive the sample therein, surfaces of the pressure chamber that define said interior volume being formed of a nickel-copper alloy, the pressure chamber having at least one inlet and at least one outlet that are in fluid communication with the interior volume; a heater thermally coupled to the pressure chamber to heat the interior volume; a cooler thermally coupled to the pressure chamber to cool the interior volume; a fluid supply module connected to the at least one inlet by a fluid conduit, the fluid conduit being formed of a nickel-copper alloy, the fluid supply module being configured to sequentially deliver fluids to the interior volume by way of the at least one inlet; and a controller operatively coupled to the heater, the cooler, and the fluid supply module; (b) sealing the sample in the interior volume of the pressure chamber; (c) flowing hydrofluoric acid into the sealed pressure chamber via the at least one inlet so as to fill the interior volume with the hydrofluoric acid, the hydrofluoric acid being in contact with the sample; (d) removing the hydrofluoric acid from the sealed pressure chamber via the at least one outlet; (e) after (d), cooling the interior volume of the pressure chamber to a temperature less than 10Â° C. using said cooler; (f) flowing liquid carbon dioxide into the sealed pressure chamber via the at least one inlet so as to fill the interior volume with the liquid carbon dioxide, the liquid carbon dioxide being in contact with the sample; (g) after (f), heating the interior volume of the pressure chamber to a temperature greater than 31Â° C. and a pressure greater than 1072 psi using said heater; and (h) after (g) , exhausting gaseous carbon dioxide from the sealed pressure chamber via the at least one outlet until the pressure therein is substantially equal to atmospheric pressure.