title: Measurement of partial pressure of gases in liquids by mass spectrometry.
abstract: The experimental setup of mass spectrometric determination of gas contents in liquids has been modified for continuous and discontinuous measurement of partial pressure of gases in liquids. The inlet system consists of a stainless steel capillary with slits covered by a silicone rubber membrane. Several gases can be measured simultaneously under static conditions and in flowing liquids. The measurement and calibration procedure is described. Results of the analysis of the test criteria, reproducibility, detection limit, response time, and depletion are presented. The difficulties in discontinuous measurement of oxygen in blood are explained by the complex permeation-diffusion process at the membrane and the form of the dissociation curve. With regard to solubility, physically dissolved gases can be determined without problems down to tensions of about 0.01 mm Hg. Continuous measurement of oxygen and carbon dioxide partial pressure in liquids, including blood, is possible with the described system.
mesh_terms: D001784:Blood Gas Analysis / Q000379:methods; D002245:Carbon Dioxide / Q000097:blood; D006801:Humans; D013058:Mass Spectrometry; D010100:Oxygen / Q000097:blood; D010313:Partial Pressure; D013053:Spectrophotometry / Q000295:instrumentation / Q000379:methods*; D014867:Water / Q000032:analysis
chemical_list: D014867:Water; D002245:Carbon Dioxide; D010100:Oxygen