Serial Dilution Calculator

What is Serial Dilution?

Serial dilution is a stepwise dilution technique used in chemistry and biology to reduce the concentration of a substance in a solution. It involves sequentially diluting a solution by a fixed factor, creating a series of solutions with decreasing concentrations. This method is crucial in various laboratory procedures, including preparing standard solutions, microbiology, and pharmacology.

How to Calculate Serial Dilution

To calculate serial dilution, follow these steps:

1. Determine the initial concentration (\(C_0\))
2. Choose the dilution factor (DF)
3. Decide on the number of dilutions (n)
4. Apply the serial dilution formula to find the concentration after each dilution

Formula

The formula for serial dilution is:

\[ C_n = C_0 \times \left(\frac{1}{DF}\right)^n \]

Where:

• \(C_n\) is the concentration after n dilutions
• \(C_0\) is the initial concentration
• \(DF\) is the dilution factor
• \(n\) is the number of dilutions

Calculation Steps

Let's calculate the concentration after 3 serial dilutions with a dilution factor of 2, starting from an initial concentration of 100 mg/mL:

1. Identify known values: \(C_0 = 100 \text{ mg/mL}\), \(DF = 2\), \(n = 3\)
2. Apply the serial dilution formula: \[ C_3 = C_0 \times \left(\frac{1}{DF}\right)^n \]
3. Substitute values and calculate: \[ C_3 = 100 \times \left(\frac{1}{2}\right)^3 = 100 \times \frac{1}{8} = 12.5 \text{ mg/mL} \]

Example and Visual Representation

Let's visualize the serial dilution process:

This visual representation shows:

• The initial concentration (blue): 100 mg/mL
• First dilution (green): 50 mg/mL
• Second dilution (yellow): 25 mg/mL
• Third dilution (red): 12.5 mg/mL

Each step reduces the concentration by half (dilution factor of 2). This process is widely used in laboratories for preparing accurate concentrations and in microbiological assays where a wide range of concentrations is needed for testing.