title: Solubility of oxygen in a seawater medium in equilibrium with a high-pressure oxy-helium atmosphere.
abstract: The molar oxygen concentration in a seawater medium in equilibrium with a high-pressure oxygen-helium atmosphere was measured directly in pressurized subsamples, using a modified version of the Winkler oxygen analysis. At a partial pressure of oxygen of 1 atm or less, its concentration in the aqueous phase was adequately described by Henry's Law at total pressures up to 600 atm. This phenomenon, which permits a straightforward determination of dissolved oxygen within hyperbaric systems, resulted from pressure-induced compensatory alterations in the Henry's Law variables rather than from a true obedience to the Ideal Gas Law. If the partial pressure of a gas contributes significantly to the hydrostatic pressure, Henry's Law is no longer adequate for determining its solubility within the compressed medium.
mesh_terms: D001274:Atmospheric Pressure; D006371:Helium; D006874:Hydrostatic Pressure; D010100:Oxygen / Q000032:analysis*; D012623:Seawater / Q000032:analysis*; D012995:Solubility
chemical_list: D006371:Helium; D010100:Oxygen