Method of making 10 mM ammonium acetate
To make a 10 mM ammonium acetate solution, the following method can be used.

The first step is to understand the molar mass of ammonium acetate. Ammonium acetate ($CH_3COONH_4 $) has a molar mass of about 77.08 g/mol. This value is crucial when calculating the mass of ammonium acetate to be used.

If you want to make a certain volume of 10 mM ammonium acetate solution, according to the volume of the desired solution (set to V liters), use the formula $n = C × V $ (n is the amount of substance, C is the amount of substance concentration) to find the amount of ammonium acetate required. For example, if you want to prepare a solution of 10 mM in 1 liter, then $n = 0.01\ text {mol/L} × 1L = 0.01 $mol.

The amount of ammonium acetate obtained can be determined according to the molar mass. For the previous example, the mass $m = n × M = 0.01\ text {mol} × 77.08\ text {g/mol} = 0.7708 $g.

Then, take a clean volumetric flask with a volume that matches the volume of the solution required. Place the accurately weighed ammonium acetate solid in it, and first dissolve it with an appropriate amount of deionized water. During the process, gently shake the volumetric flask to help it dissolve. After the ammonium acetate is completely dissolved, use deionized water bandwidth evaluation to the scale line. During bandwidth evaluation, the line of sight should be flush with the scale line of the volumetric bottle and the lowest point of the concave liquid level of the solution to ensure that the solution volume is accurate.

At this point, the 10 mM ammonium acetate solution is prepared. During the preparation process, the weighing needs to be accurate, the dissolution needs to be complete, and the bandwidth evaluation should be careful to obtain a solution with accurate concentration.