What is serial dilution and provide an example you might use in the laboratory
Serial dilution is a process used in the laboratory to make a range of solutions with decreasing concentrations from an original stock solution. It involves repeatedly diluting a solution with a known concentration to create a series of solutions with lower and lower concentrations.
For example, let's say we have an initial stock solution of a substance with a concentration of 10% (w/v). We want to prepare a series of solutions with concentrations of 5%, 2.5%, 1.25%, and 0.625%. To achieve this, we can perform a serial dilution as follows:
1. Take 1 mL of the stock solution and transfer it to a new container (e.g., a test tube) containing 9 mL of a diluent (e.g., water or a buffer solution). This 1:10 dilution results in a solution with a concentration of 1%.
2. Take 1 mL of the 1% solution and transfer it to another container containing 9 mL of diluent. This 1:10 dilution results in a solution with a concentration of 0.1% (10 times more diluted than the previous solution).
3. Repeat step 2 two more times, each time taking 1 mL of the previous solution and transferring it to 9 mL of diluent. This will result in further dilutions of 0.01% and 0.001% (or 10^-2% and 10^-3%, respectively).
By following this serial dilution process, we have successfully prepared a series of solutions with decreasing concentrations from the initial 10% stock solution. These solutions can then be used for various experiments or tests that require different concentrations of the substance.