title: Use of carbon dioxide- and oxygen-tonometered phosphate-bicarbonate-chloride-glycerol-water mixtures for calibration and control of pH, pCO2, and pO2 electrode systems.
abstract: Calibration of pH, PCO2, and PO2 electrode systems of modern blood-gas analyzers, designed with one sample cuvet for measurement, is mostly performed separately with buffer solutions of known pH, PCO2, and PO2 for doing such calibrations simultaneously, containing phosphate, bicarbonate, and chloride in glycerol-water mixtures as solvent. A method is suggested for computing the relation between pH and log PCO2 of these solutions in equilibrium with carbon dioxide gas. It is demonstrated that a solution of phosphate (Na2HPO4, KH2PO4, each 25 mmol/liter), bicarbonate (NaHCO3, 30 mmol/liter), and chloride (Nacl, 30 mmol/liter) in glycerol-water mixture (3/7 by vol) and equilibrated with CO2 in air (4 vol/100 vol) and CO2 in  nitrogen (8 vol/100 vol), respectively, makes possible acurate and simultaneous calibration of the pH, PCO2, PO2 electrodes of a Corning Model 165 blood-gas analyzer. Similar solutions may also be used for quality-control of blood-gas measurement.
mesh_terms: D001639:Bicarbonates; D001769:Blood; D001784:Blood Gas Analysis / Q000379:methods*; D002021:Buffers; D002245:Carbon Dioxide / Q000097:blood*; D002712:Chlorides; D004566:Electrodes; D005069:Evaluation Studies as Topic; D005990:Glycerol; D006801:Humans; D006863:Hydrogen-Ion Concentration; D008433:Mathematics; D009994:Osmolar Concentration; D010100:Oxygen / Q000097:blood*; D010313:Partial Pressure; D010710:Phosphates
chemical_list: D001639:Bicarbonates; D002021:Buffers; D002712:Chlorides; D010710:Phosphates; D002245:Carbon Dioxide; D005990:Glycerol; D010100:Oxygen