Dilutions for GEL AMR EC CFU Kits

GEL AMR EC CFU Kits test groundwater and surface waters without requiring dilutions. Dilutions for this test are only required for wastewater testing.

Diluent

​Dilution water needs to be free of E. coli, preferably sterile water, such as:

 

  • Standard Methods phosphate buffer
  • Autoclaved or boiled reagent water
  • Autoclaved or boiled tap water
  • High quality, certified bottled water. Some bottled waters are produced locally and are microbiologically unsafe.
  • Distilled water from a commercial source and sold in properly sealed bottles. While not necessarily sterile, it should be free of E. coli.

Wastewater Testing

1:100 Dilution

Steps for 1:100 dilution:

  • Collect 10 mL sample with a pipette
  • Add 10 mL sample to Thio-Bag
  • Add 90 mL diluent to Thio-Bag
  • Take 10 mL from the above diluted sample, add it to a second 100 mL Thio-Bag. Add 90 mL of diluent.
  • Add our AMR EC growth medium to the second Thio-Bag and dissolve the medium
  • Pour contents of the second Thio-Bag into the GEL Bag and proceed with testing procedures

1:1000 Dilution

Steps for 1:1000 dilution:

  • Collect 10 mL sample with a pipette
  • Add 10 mL sample to Thio-Bag
  • Add 90 mL diluent to Thio-Bag
  • Take 10 mL from the above diluted sample, add it to a second 100 mL Thio-Bag, and then add 90 mL of diluent
  • Take a 10 mL sample from the second Thio-Bag, add it to a third 100 mL Thio-Bag, and then add 90 mL of diluent. 
  • Add our AMR EC growth medium to the third Thio-Bag and dissolve the medium
  • Pour contents of the third Thio-Bag into the GEL Bag and proceed with testing procedures