To prepare 16mM ammonium acetate buffer 90:10 in acetonitrile, please follow these step-by-step instructions:

  1. Buffer Stock Solution (500 mM Ammonium acetate aqueous solution): Weigh 3.85 g ammonium acetate and quantitatively transfer to a 100 mL volumetric flask. Dilute to mark with DI water and mix until dissolved. Filter through 0.45um nylon filter. (This makes a 500 mM solution and should be stored in 2-8°C.)

  2.  90/10 Acetonitrile Mixture: Measure 32 mL Buffer Stock Solution into a 1000 mL volumetric flask.  Measure 68 mL of DI water and add to flask.  Dilute to mark with acetonitrile and mix well.  (We suggest to filter this mobile phase with 0.45um nylon membrane before use.)
  3. This makes your mobile phase solution “16 mM ammonium acetate in 90:10 acetonitrile: buffer”

These instructions help to ensure you get reproducible results with respect to the mobile phase used in our Application Notes.