# Calculating volume of 0.5M EDTA required for preparation of 100 ml of 1 mM EDTA

Concentrated 0.5 M EDTA stock solution can be diluted to prepare 1 mM EDTA solution. Following procedure can be used to calculate amount of 0.5M EDTA solution required to prepare 100 ml of 1 mM EDTA solution

# Procedure:

Step 1: Convert all concentration unit to either molar or millimolar.

The SI prefix “milli” represents a factor of 10-3. Here we convert stock solution concentration (0.5M EDTA) to millimolar (mM).

1 mM   =     10-3 M = 0.001 M

OR                               1 M      =      1000 mM
0.5 M   =      0.5 x 1000 mM

0.5 M   =      500 mM

Stock solution concentration is 500 mM.

Step 2: Calculate required amount of stock solution (500 mM EDTA) to prepare 1000 ml of 1 mM EDTA

Formula:

Cf: Concentration of final solution i.e., 1 mm EDTA
Vf: Volume of the final solution i.e., 100 ml
CS: Conc. of stock solution i.e., 500 mM

VS: Volume of stock solution – To be calculated

Place all values in the formula

1 x 100 = 500 x VS                                                                            VS = 0.2 ml

Step 2: Calculate the amount of water

You want to prepare 100 ml solution of which 0.2 ml is 0.5M EDTA stock solution. Rest of the amount will be water which is calculated by subtracting 0.2 ml from 100 ml.

Vf     : Volume of the final solution i.e., 100 ml
Vs    : Volume of the stock solution i.e., 0.2 ml

Amount of diluent i.e., water: 100 – 0.2 = 99.8 ml

Conclusion: To prepare 100 ml of 1 mM solution of EDTA from 0.5M EDTA stock solution, you need to mix 0.2 ml of 0.5M EDTA stock solution and 99.8 ml water.