Mike Barnkob:Protocols/Bacterial/LB agar plates
Preparing LB plates with ampicillin
Recipe for preparing LB ampicillin plates.
Weigh out the following into a 0.5L flask:
- LB Broth Ezmix, 14.2mg
- dH20, 400 ml
Note: Makes about 25 plates.
- Mix LB broth mix into water by swirling
Note: powder left on the sides of the flask will caramelize on the glass during autoclaving.
- Cover flask with aluminum foil and label with autoclave tape.
- Autoclave on the liquid setting for 20 minutes
- Allow the agar solution to cool to 55°C by placing in 55°C water bath.
- Add ampicillin to a concentration of 100 µg/mL (0.4 ml of 100mg/mL).
- Pour ~20mL of LB agar per 10cm polystyrene Petri dish
Note: Before pouring, burn the flask head with a Bunsen burner.
Note: Pour slowly from the flask into the center of the petri dish. When the agar has spread to cover about 2/3 of the dish stop pouring and the agar should spread to cover the entire plate.
- Place the lids on the plates and allow them to cool for 30-60 minutes. Let sit for several more hours or overnight.
- Label the bottom of plates with antibiotic and date and store in plastic bags or sealed with parafilm at 4°C.
Note: Plates should be good for 1-2 months.