You took 0.99ml of a hexokinase assay solution and added 10 ul of an unknown glucose sample. The absorbance at 340nm is 0.422 the extinction coefficient is 6.22x10^3 the molecular mass of glucose is 180.16g/mol. What is the concentration of glucose in the original sample...
In moles/liter? And in mg%?
To determine the concentration of glucose in the original sample, we need to follow a few steps:
Step 1: Calculate the molar concentration of the hexokinase assay solution.
Since we know the volume of the hexokinase assay solution added is 0.99 mL, we need to convert it to liters by dividing by 1000:
Volume = 0.99 mL ÷ 1000 = 0.00099 L.
Step 2: Calculate the number of moles of glucose using the absorbance and the extinction coefficient.
Using the Beer-Lambert law, we know that absorbance (A) is equal to the molar absorptivity (extinction coefficient, ε) multiplied by the path length (in this case, 1 cm) and concentration (C):
A = ε × l × C.
Here, A = 0.422, ε = 6.22 × 10^3, and l = 1 cm.
Rearranging the equation to solve for C, we get:
C = A / (ε × l) = 0.422 / (6.22 × 10^3 × 1).
Step 3: Convert the concentration from moles per liter (M) to moles per milliliter (mM).
Since the assay solution volume is given in milliliters, we need to convert the concentration from M to mM by multiplying by 1000:
Concentration in mM = C × 1000.
Step 4: Calculate the concentration of glucose per liter in moles.
Since we added 10 μL (microliters) of the glucose sample to the 0.99 mL of assay solution, the overall volume is 1 mL. We need to convert it to liters by dividing by 1000:
Total volume = (0.99 mL + 10 μL) ÷ 1000 = 0.001 mL.
To calculate the concentration of glucose in moles per liter (M), we can use the formula:
Concentration in M = Concentration in mM × (total volume in liters / sample volume in liters).
Concentration in M = (C × 1000) × (0.001 L / 0.00099 L).
Step 5: Convert the concentration from moles per liter (M) to milligrams per deciliter (mg%).
To convert moles per liter (M) to milligrams per deciliter (mg%), we need to know the molecular mass of glucose, which is given as 180.16 g/mol:
Concentration in mg% = Concentration in M × Molecular mass of glucose × 100.
Concentration in mg% = (Concentration in M × 180.16) × 100.
By substituting the values from the previous calculations into these formulas, you should be able to obtain the concentration of glucose in moles per liter (M) and milligrams per deciliter (mg%).