Overview
As an inert gas, nitrogen is essential for cryopreservation, pharmaceutical packaging, and sterile purging. The EP provides specifications for both standard and low-oxygen nitrogen grades.

EP Monograph Requirements

• Grades:
  • Nitrogen: ≥99.5%
  • Low-oxygen nitrogen: <1% O₂
• Impurities: Oxygen, water vapor, CO, CO₂, hydrocarbons
• Tests: Identity confirmed via gas chromatography or thermal conductivity; oxygen and moisture measured using electrochemical and hygrometer techniques.

Testing Techniques

• Gas chromatography (N₂ purity, hydrocarbons)
• Electrochemical O₂ sensors (for low-O₂ grade)
• Electrolytic hygrometer (water content)
• IR and NDIR analysis (CO, CO₂)

Applications

• Freeze-drying (lyophilization)
• Cleanroom purging
• Biologic preservation
• Inert packaging environments