A Technique for Measuring the Solubilities of Gases in Liquids

Abstract : Experiments are planned for measuring the solubilities of nitrogen, helium, and hydrogen in water, blood, and other tissues at 37 C and pressures ranging from 1 to 10 ATA. We describe a protocol for these experiments, which consist of measuring the change in total pressure that occurs during equilibration of the gas phase with the condensed phase in a closed container after an abrupt elevation of the partial pressure of the test gas. We derive the equations to compute the Henry's coefficient or the Ostwald coefficient from the results of that experiment. Experimental conditions are optimized based on a formal propagation of error. The error analysis shows that gas leakage is by far the most serious potential source of error. The technique for measuring leakage is discussed; actual solubility measurements will proceed when the error from this source is deemed acceptably small.