This is a cached page for the URL ( To see the most recent version of this page, please click here.
Protocol Online is not affiliated with the authors of this page nor responsible for its content.
About Cache
Microbiology - Serial Dilution

Microbiology - Serial Dilution

Jeff Lawrence

1. An undiluted (stock) solution is termed the 100 dilution. This may be a chemical solution, or a suspension of bacteria or bacteriophage.

2. Typical diluions are 10-fold dilutions; each dilution is 1/10th the concentration of the previous dilution. The first 10-fold dilution is termed the 10-1 dilution.

3. Each subsequent dilution is made from a previous dilution. Here is a series of 10-fold dilutions:
 	Start:	100 mL	100	100 mL	10-1	100 mL	10-2	100 mL	10-3 	Add:	+900 mL	Buf.	+900 mL Buf.	+900 mL Buf.	+900 mL Buf. 	Yield:	1000 mL	10-1	1000 mL	10-2	1000 mL	10-3	1000 mL	10-4 
4. Since 100 mL of the 10-1 dilution is used to make the 10-2 dilution, only 900 mL remains for use.

5. The buffer used for dilution depends on the substance being diluted:
 	Substance		Dilution Buffer 	Chemical		Sterile water 	DNA			TE 	Enzyme			Enzyme Dilution Buffer (with Glycerol) 	Bacteriophage P1	5 mM CaCl2, 10 mM MgSO4 	Bacterial cells		0.9% NaCl