Purpose: Compare evaporation rates between Soft-Guard™ caps and market-leading / private-label caps with pre-slit septa.

1. Materials & Methods

• Sample Setup:
  • 10 vials labeled #1–#10
  • 5 Market Leader (M) caps and 5 Soft-Guard™ (SG) caps
  • AQ Brand Maximum Recovery screw-top vials used
• Procedure:
  • Empty vials with caps weighed (tare weight, w_tare)
  • 800 µL methanol added; vials weighed again (w₀)
  • Vials stored at room temperature for ~161 hours
  • Final weight recorded (w₁₆₁)

2. Visual Observations

• Market-Leading Caps:
  • Septa appeared flat when loose
  • Became concave when attached to vials
• Soft-Guard™ Caps:
  • Loose caps showed convex septa with slightly open slit (“smiling caps”)
  • When tightened, slit closed and surface appeared flat to slightly convex

3. Results

• Market-leading pre-slit caps lost twice as much solvent compared to Soft-Guard™ caps, despite Soft-Guard™ caps initially showing more exposed slits when loose.

Cap Type	Average % Loss
Market Leader (M)	5.4%
Soft-Guard™ (SG)	2.4%

 

 

Key Takeaways

• Soft-Guard™ caps significantly reduce evaporation compared to market-leading alternatives.
• Design features (slit closure upon tightening) contribute to improved performance.