Mobile Phase Preparation for BIST™ A and BIST™ A+ Columns

BIST A/A+ Mobile Phase Concentrate – TMDAP

The following procedures will produce a mobile phase solution containing 80% MeCN, 20% water, and 5 mM N,N,N’,N’-Tetramethyl-1,3-diaminopropane (TMDAP) at pH 4.0. The resulting concentrations can be modified for your particular needs by adjusting the initial volumes of solution.

Chemicals

HPLC-grade Acetonitrile (CAS #75-05-8)

HPLC-grade Water

99% N,N,N’,N’-Tetramethyl-1,3-diaminopropane (CAS #110-95-2)

HPLC-grade Formic acid (CAS #64-18-6)

Equipment

500 mL graduated cylinder

500 mL beaker

1 L solvent bottle (qty. 2)

Analytical scale

pH meter

Magnetic stirrer

100 mM TMDAP pH 4.0 Buffer Preparation:

1. Ensure you are wearing proper PPE: gloves, lab coat, lab goggles and working under a fume hood.
2. Weigh 6.5 g of TMDAP into the 500 mL beaker. 
3. Add about 400 mL of water to the 500 mL beaker.
4. Place the beaker on the stir plate with the stir bar in the beaker.
5. Lower the pH probe into the beaker and turn on the stirrer.
6. Slowly add Formic acid into the beaker, monitoring the pH level until it reaches 4.0. This step usually consumes about 5.0-6.0 mL of Formic acid.
7. Pour the contents of the beaker (except the stir bar) into the 500 mL graduated cylinder and fill the graduated cylinder to the 500 mL mark with water.
8. Transfer the contents of the graduated cylinder into the 1L solvent bottle. 

This will create 1L of 100 mM TMDAP pH 4.0 buffer stock solution.

9. In a 1L bottle, mix 150 mL of water, 50 mL of buffer stock solution, and 800 mL of Acetonitrile to produce a 80/20/5 mM Acetonitrile/Water/TMDAP-formate mobile phase.

Notes:

• This MP can be prepared with a concentration of acetonitrile up to 90%. Higher concentration of acetonitrile will make the MP non-homogeneous.