Systems and methods for separating hydrogen sulfide from carbon dioxide in a high-pressure mixed stream are disclosed herein. The methods include receiving the high-pressure mixed stream in an oxidation reactor and at an inlet pressure of at least 0.3 megapascals. The high-pressure mixed stream includes 0.01 to 5 mole percent hydrogen sulfide and at least 90 mole percent carbon dioxide. The methods further include oxidizing the high-pressure mixed stream with an oxidant to generate a high-pressure oxidized stream, includes oxidized hydrogen sulfide and carbon dioxide, at an oxidation pressure of at least 0.3 megapascals. The methods also include separating the high-pressure oxidized stream into an oxidized hydrogen sulfide product and a carbon dioxide product and generating the carbon dioxide product at a pressure of at least 0.3 megapascals. The systems include the high-pressure mixed stream, an oxidation reactor, and a separation assembly.

Provided herein is technology relating to the amplification-based detection of bisulfite-treated DNAs and particularly, but not exclusively, to methods and compositions for multiplex amplification of low-level sample DNA prior to further characterization of the sample DNA. The technology further provides methods for isolating DNA from blood or blood product samples, e.g., plasma samples.