Search PubMed⌕ Search

Biomedical subjects

U Smidt

Publications and source records attributed to U Smidt.

At least 73 records · Page 4Linked to original sources
PubMed1975

Measurement of partial pressure of gases in liquids by mass spectrometry.

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.

Blood Gas Analysis↗
PubMed1975

Water-vapor-independent inlet system for a respiratory mass spectrometer: application to experiments with a human centrifuge.

When using a two-stage inlet system in mass spectrometric analysis of permanent gases, changes of water-vapor partial pressure from inspiration to expiration considerably impede the measurements. With this type of gas inlet system, use of a mass spectrometer for measurements on a human centrifuge is rather limited. Introduction of a water-vapor - independent three-stage inlet system permits quantitative analysis of gas mixtures even if the water vapor pressure varies quickly with time. The expiratory oxygen and carbon dioxide partial pressure curves should exemplify that even under extreme acceleration conditions the three-stage system permits simultaneous and continuous mass spectrometric analysis of respiratory gases, with satisfactory response time and a simple experimental arrangement. The method described thus opens up new experimental possibilities for the investigation or respiratory gas exchange phenomena under acceleration conditions.

Adult↗