Chlorophyll A Testing: Part I: Filtration



  • Vacuum
  • Plastic tubing
  • Filtration apparatus with receiver for dispensing filtrate from sample
  • Forceps / tweezers
  • Aluminum squares (~2”)
  • Filters (24 mm GF/F Whatman)
  • Permanent marker (fine)
  • DI – labeled squirt bottle
  1. Set up filtration station using a 200 mL Filtration funnel (Gelman Polysulfone) and filter base. Keep lighting dim to avoid unnecessary exposure of samples to light.
  2. Rinse setup with distilled water, and run vacuum to dry.
  3. Load filter onto the filtration bed and twist on funnel. Rinse with distilled water to wet filter and run vacuum pump briefly.
  4. Add 200 mL of sample to funnel, turn on vacuum pump and leave running until filter is partially dried.
  5. After sample has been filtered, remove funnel (gently twisting counter-clockwise) and remove filter from bed using forceps/tweezers.
  6. Center filter on 2” x 2” aluminum foil, and fold in half, rotate foil, and fold again. Label foil in permanent marker with “Chl a”, date, group, site ID, and volume of sample filtered (200 mL).
  7. Repeat filtration for each site as needed.
  8. Store foil-wrapped filters in freezer for at least 24 hours.