Overview
Oxygen is one of the most critical medicinal gases, essential for respiratory therapy, anesthesia, cell culture, and emergency medicine. The European Pharmacopoeia (EP) outlines monographs for three grades of oxygen: Oxygen, Oxygen 93%, and Oxygen 98%. Each grade has specific purity, identity, and impurity requirements to ensure safe patient use and suitability for pharmaceutical manufacturing.

EP Monograph Requirements

• Purity:
  • Oxygen: ≥99.5%
  • Oxygen 98: ≥96.0%
  • Oxygen 93: 90.0%–96.0%
• Impurities: Strict limits for carbon monoxide (CO), carbon dioxide (CO₂), nitrogen (N₂), argon (Ar), moisture, and hydrocarbons.
• Tests: Identification via paramagnetic analysis or IR spectroscopy; impurity detection using electrochemical cells, gas chromatography, or chemiluminescence for NO/NO₂.

Testing Techniques

• Paramagnetic analysis (O₂ identity and concentration)
• Chemiluminescence (NO/NO₂)
• Electrochemical analysis (CO, residual O₂)
• Electrolytic hygrometer (moisture content)
• IR/NIR spectroscopy (confirmation and trace analysis)

Applications

• Inhalation therapy, emergency care
• Sterile manufacturing environments
• Cell and tissue culture
• Medical device operation (ventilators, incubators)