You have a stock solution of 100mg/100ml methylene blue and you need 6.0 ml of final solution at 2mg/100ml. Design a serial dilution using volumes between 0.1 and 10 ml. Final volume must be 6ml.
To design a serial dilution using volumes between 0.1ml and 10ml, and ultimately obtain a 6ml solution at 2mg/100ml concentration, here's how you can proceed:
1. Determine the starting concentration and volume of the stock solution:
- The stock solution has a concentration of 100mg/100ml.
- Let's assume the starting volume of the stock solution is V1 ml.
2. Determine the final volume and concentration you want:
- The final volume of the diluted solution should be 6ml.
- The desired final concentration is 2mg/100ml.
3. Calculate the dilution factor:
- The dilution factor is the ratio of the final volume to the original volume.
- Dilution factor = final volume / initial volume = 6ml / V1 ml
4. Calculate the dilution factor required to achieve the desired final concentration:
- The desired final concentration is 2mg/100ml.
- Dilution factor = (concentration of the stock solution) / (desired final concentration) = (100mg/100ml) / (2mg/100ml)
5. Equate the two dilution factors and solve for V1:
- (100mg/100ml) / (2mg/100ml) = 6ml / V1 ml
- Simplifying: 50 = 6 / V1
- Cross-multiplying: V1 = 6 / 50 * 1
- V1 = 0.12ml
6. Once you have the initial volume (V1), you can proceed with the serial dilution:
- Transfer 0.12ml of the stock solution to a container.
- Add an appropriate volume of diluent (e.g., 5.88ml of water) to bring the total volume to 6ml.
- Mix the solution thoroughly.
This will yield a final solution of 6ml with a concentration of 2mg/100ml, achieved through a serial dilution starting with a 100mg/100ml stock solution.