Sorption of parabens by fluoropolymer or fluoropolymer laminated flexible tubing

Earlier studies using methylparaben and propylparaben showed extensive losses due to sorption by silicone, polyvinyl chloride, and other flexible tubing. As much as 100% loss of propylparaben and significant loss of methylparaben was reported within 24 hours using Tygon, Clearflo, or Silastic tubing. The fluoropolymer Teflon FEP did not show sorption losses. The current study was conducted using three different fluoropolymer resin tubing pieces (FEP, PFA, and NXT or PTFE) as well as a Tygon tubing lined with FEP to show that these do not show paraben sorption losses over an extended period of time. The results of this study show that sorption losses can be avoided or reduced by proper selection of flexible tubing.