1. What is Serial Dilution?

Serial dilution is a stepwise dilution of a substance in solution, typically to reduce the concentration of cells or particles by a consistent dilution factor at each step. It's commonly used in microbiology, biochemistry, and medical laboratories.

2. How Does the Calculator Work?

The calculator uses the serial dilution formula:

Where:

• \( C_t \) — Final concentration (cells/mL)
• \( C_0 \) — Initial concentration (cells/mL)
• \( DF \) — Dilution factor (unitless)
• \( n \) — Number of dilution steps (unitless)

Explanation: Each dilution step reduces the concentration by the dilution factor. After n steps, the concentration is reduced by DF to the power of n.

3. Importance of Serial Dilution

Details: Serial dilution is essential for creating solutions of precise concentrations, counting cells via plating, preparing standard curves, and working with samples that have high initial concentrations.

4. Using the Calculator

Tips: Enter initial concentration in cells/mL, dilution factor (typically 10 for decimal dilutions), and number of dilution steps. All values must be positive numbers.

5. Frequently Asked Questions (FAQ)

Q1: What's a typical dilution factor used in labs?
A: Common dilution factors are 10 (1:10) or 2 (1:2), but any factor can be used depending on the application.

Q2: How do I perform a serial dilution in practice?
A: Transfer a fixed volume to a new tube containing diluent, mix thoroughly, and repeat for each step. Always use fresh pipette tips.

Q3: Why does the concentration decrease exponentially?
A: Because each dilution step applies the dilution factor multiplicatively to the previous concentration.

Q4: What's the maximum number of practical dilution steps?
A: Typically 6-8 steps, as further dilutions may introduce significant pipetting errors and become too dilute to measure.

Q5: Can I use this for non-cell dilutions?
A: Yes, the same principle applies to any solute being diluted (proteins, chemicals, etc.), just change the concentration units.