Antibiotic concentrations for E. coli selection

The following list shows recommended antibiotic concentrations for LB media or agar plates.

Antibiotic	Concentration
Ampicillin	100 μg/mL
Bleocin	5 μg/mL
Carbenicillin	100 μg/mL
Chloramphenicol	25 μg/mL
Coumermycin	25 μg/mL
Gentamycin	10 μg/mL
Kanamycin	50 μg/mL
Spectinomycin	50 μg/mL
Tetracycline	10 μg/mL

Example: To make 100 mL of LB/ampicillin growth media, add 100 μL of a 100 mg/mL ampicillin stock (1000X stock) to 100 mL of LB.

Unless otherwise indicated, the antibiotic powder can be dissolved in H₂0. Addgene recommends making 1000X stock solutions and storing aliquots at -20^oC.

Reagent	Catalog Number
Ampicillin	EMD Chemicals #171254
Bleocin	EMD Chemicals #203408
Carbenicillin	EMD Chemicals #205805
Chloramphenicol	EMD Chemicals #220551 (dissolve with EtOH)
Coumermycin	Sigma #C9270 (dissolve with DMSO)
Gentamycin	EMD Chemicals #345814
Kanamycin	EMD Chemicals # 420311
Spectinomycin	EMD Chemicals # 567570
Tetracycline	EMD Chemicals # 583411

Please note that the catalog numbers given in the list above are only examples, and there are many additional companies that supply these reagents.