Preparation of stock solution of chloramphenicol


  • Chloramphenicol is a broad spectrum antibiotics which is effective against both gram positive and gram negative bacteria.
  • It is bacteriostatic agent.
  • It inhibits bacterial protein synthesis by irreversibly binding to 50S ribosomal subunit and inhibiting peptidyl transferase catalytic function.


  • Reagents
    • Chloramphenicol
    • 70% ethanol
  • Equipment and disposables
    • Measuring cylinder
    • Conical flask / Beaker / 15 ml screw-capped tube
    • Magnetic stirrer


  • 34 mg/ml chloramphenicol
  • 70% ethanol


Preparation of 10 ml of chloramphenicol stock solution in 70% ethanol


Step 1: To prepare 10 ml of stock solution of chloramphenicol, weigh out 340 mg of chloramphenicol. Transfer it to 15 ml screw-capped tube. Add 9 ml of 70% ethanol. Mix until all chloramphenicol is dissolved completely.


  • We recommend to use 15 ml screw-capped tube with millilitre marks. Transfer all the contents in it. Add 9 ml 70% ethanol and mix the content by rotating the tube. Once the content is mixed, make up the volume 10 ml.


  • Do not dissolve in 10 ml of deionized / Milli-Q water. In most cases, solution volume increases when the large amount of solute dissolves in solvent.

Step 2: Adjust the volume to 10 ml with d70% ethanol. Mix it again.


Store the solution in small aliquots (1 ml) at -20°C for long time.


  • It is recommended to store the chloramphenicol stock solution in small aliquots.


A selection marker for bacterial culture during gene cloning experiments.

Follow the table to prepare chloramphenicol solution of various volume (5 ml, 10 ml, 25 ml, 100).
Reagents / Volume 5 ml 10 ml 25 ml 100 ml
Chloramphenicol 170 mg 340 mg 850 mg 3400 mg
70% Ethanol Adjust the final volume to 5 ml Adjust the final volume to 10 ml Adjust the final volume to 25 ml Adjust the final volume to 100 ml