title: Sulfur hexafluoride and perfluoropropane do not escape from a plastic syringe closed with a stopcock.
abstract: OBJECTIVE
  To evaluate during various intervals of time the escape of long-acting gases contained in a plastic syringe closed with a stopcock or a plastic cap.
  
  
  METHODS
  A 60-ml plastic syringe was filled or partially filled with a long-acting gas, either sulfur hexafluoride or perfluoropropane. The tip of the syringe was closed with either a stopcock or the syringe's plastic cap. After various intervals of time, the concentration of the long-acting gas in the syringe was measured by gas chromatography.
  
  
  RESULTS
  The concentration of both long-acting gases was higher than 98% at 24 hours after filling when the syringe was closed with a stopcock; however, it was less than 41% when the syringe was filled and capped tightly with its plastic cap.
  
  
  CONCLUSIONS
  The proportion of long-acting gases escaping in 24 hours from a filled syringe capped with a stopcock is clinically insignificant.
authors.affiliation: Department of Ophthalmology, Osaka University Medical School, Suita, Japan.
authors.forename: M
authors.initials: M
authors.lastname: Ohji
authors.forename: F
authors.initials: F
authors.lastname: Adachi
authors.forename: Y
authors.initials: Y
authors.lastname: Tano
mesh_terms: D002849:Chromatography, Gas; D004058:Diffusion; D005466:Fluorocarbons / Q000032:analysis*; D013459:Sulfur Hexafluoride / Q000032:analysis*; D013594:Syringes; D013997:Time Factors
chemical_list: D005466:Fluorocarbons; C042852:perflutren; D013459:Sulfur Hexafluoride