# Luckau Protocols:MgCl2

 MgCl2 Protocol

## Purpose

• In the Clark Lab, 500 mM MgCl2 is used as a stock solution for making the PCR Buffer series (A through H)

## Info

• Magnesium chloride, MgCl2 (anhydrous)
we currently use Acros Organics, Product number 223211000, Lot A0316391
• MW = 95.21 g/mol

• Note: MgCl2 crystals are hygroscopic, meaning they attract water molecules from the air, so the powder can get "sticky". This doesn't affect the ability for the powder to dissolve, but care should be taken to keep the lid on the stock powder bottle as much and as tight as possible
• Note: the dissolving of MgCl2 with H2O is an exothermic reaction - you may notice the solution heat up and fizz a bit when adding water to the powder. Just don't stand over it and inhale, as a general rule. Otherwise, this is normal.

## To make 150 mL of 500 mM MgCl2

### Calculations

• $150 \mathrm{mL} \bullet \tfrac{500 \mathrm{mmol}}{\mathrm{L}}\ \bullet \tfrac{\mathrm{L}}{1000 \mathrm{mL}}\ \bullet \tfrac{95.21 \mathrm{g}}{\mathrm{mol}}\ = 7.14075 \mathrm{g}$

### Protocol

1. Using digital scale, place 7.14 g MgCl2 powder into weigh boat
2. In 250 mL glass media bottle, mix 7.14 g MgCl2 with approximately 100 mL H2O
3. Place bottle on magnetic stirrer with stirbar until dissolved
4. Add H2O to bring volume to 150 mL

• If this 500 mM MgCl2 is being used as the stock solution for PCR Buffers A-H, then leave in the 250 mL glass media bottle and store at room temperature on the chemical shelf.