Question

12. For the purification of DHFR experiment, the protein was eluted with 0.300 M imidazole. the elution fractions that were dialyzed equaled 3.00 ml. The dialysis bag was placed in 500.0 mL of dialysis buffer that contained no imidazole. Assume a total volume of 503.00 mL and the solution reach equilibrium. What is the equilibrium concentration of imidazole in the sample?

Answer 1

Dialysis experiments are based on the fact that the final concentration in the whole mixture of sample and dialysis buffer is the same. When the solution reaches equilibrium, the concentration of imidazole can be calculated as:

$C_{eq}=\frac{C_{i}\cdot V_{i}}{C_{eq}}=\frac{0.300M\cdot 3.00mL}{503.00mL}=0.00179M$

This will be the concentration in the sample once equilibrium is reached.