You have isolated compound X from panda pancreas. You started with a whole pancreas, and finished up with 5 ml of a pure solution of X. Assume you got 100% recovery of compound X. You take 300 µl of this solution, and add it to 1.7 ml of buffer. The absorbance of this dilute solution at 340nm was 0.557 The molar extinction coefficient at 340nm for compound X is 13,200 l/mol cm. The formula weight of compound X is 14,000 g/mol How many total mg of X are there in the panda pancreas?

Question

You have isolated compound X from panda pancreas. You started with a whole pancreas, and finished up with 5 ml of a pure solution of X. Assume you got 100% recovery of compound X. You take 300 µl of this solution, and add it to 1.7 ml of buffer. The absorbance of this dilute solution at 340nm was 0.557 The molar extinction coefficient at 340nm for compound X is 13,200 l/mol cm. The formula weight of compound X is 14,000 g/mol How many total mg of X are there in the panda pancreas?

How would you approach solving this problem? I used A=Ecl to find the concentration of the dilute solution (.0000422 mol/L, I believe), but I am not sure where to go from there. ANY help would be greatly appreciated!

Answer 1

You're right that C = 4.22E-5 M. So M x L = mols = 4.22E-5 mol/L x 2E-3 L = mols X in that final 2 mL sample that was measured. But that also is the mols in that 300 uL taken from the original sample. Convert to grams. That is g = mols x molar mass = ? That gives you grams in that 300 uL. Now all you need to do is to correct for the dilution.

So grams in that 300 uL x (5 mL/300E-6) and convert to mg.
Post your work if you get stuck.

Answer 2

Thank you for your help!!

Answer 3

To find the total mg of compound X in the panda pancreas, we need to approach the problem step-by-step. Here's how we can solve it:

1. Start by finding the concentration of compound X in the dilute solution using the Beer-Lambert Law equation, A = εcl.

Given:
Absorbance (A) = 0.557
Molar Extinction Coefficient (ε) = 13,200 L/mol cm
Path Length (l) = 1 cm

Rearranging the equation: c = A / (ε l)

c = 0.557 / (13,200 * 1)
c = 4.22 × 10^-5 mol/L

2. Next, calculate the number of moles of compound X in the 300 µl (0.3 ml) of the dilute solution.

Given:
Volume (V) of dilute solution = 0.3 ml = 0.3 cm^3
Concentration (c) = 4.22 × 10^-5 mol/L

Moles (n) = c * V
n = (4.22 × 10^-5 mol/L) * (0.3 cm^3)
n = 1.266 × 10^-5 mol

3. Calculate the mass of compound X in grams.

Given:
Formula weight (FW) of compound X = 14,000 g/mol

Mass (m) = n * FW
m = (1.266 × 10^-5 mol) * (14,000 g/mol)
m = 0.177 g

4. Convert the mass of compound X to milligrams.

Mass (m) = 0.177 g * 1000 mg/g
m = 177 mg

Therefore, there are approximately 177 mg of compound X in the panda pancreas.

Please note that the 100% recovery assumption could affect the accuracy of the result, as it is rare to achieve complete recovery in practical laboratory scenarios.