The instructions in the experiment tell you to prepare a buffer and a mixed mobi

Question

The instructions in the experiment tell you to prepare a buffer and a mixed mobile phase. Prepare 1 liter of a buffer solution containing 0.5% (w/v) ammonium acetate and 2% (v/v) glacial acetic acid using deionized water. Use this buffer to prepare 200 mL of mixed mobile phase solution: 25% (v/v) acetonitrile in 75% (v/v) of the buffered water. Calculate the mass of ammonium acetate and the volume of acetic acid you will use to prepare the buffer. Calculate the volumes of acetonitrile and buffer you will use to prepare the mixed mobile phase. Describe how you will make this solution (glassware, etc.).

Explanation / Answer

a) It is required to prepare 0.5% ammonium acetatein one liter.

    0.5% w/v means, 0.5 g of solute present in 100 mL of solution. Thus 0.5 % of one liter solution contains 5 g of ammonium acetate in one liter solution.

Similarly 2% v/v denotes 2mL of solute present in 100mL of solution. Thus 2% of one liter buffer contains 20mL of glacial acetic acid in it.

Thus 5g of ammonium acetate and 20 mL of glacial acetic acid to be taken in 1000mL volumetric flask and made upto the mark by adding deionised water to get the required buffer.

b) 25% v/v aceto nitrile has 25 ml of acetobitrile and 75mL of solvent.(buffered water. To prepare 200mL of such solution, we need to take 50mL of acetonitrile and 150mL of buffered water using measuring jars.

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