Luckau Protocols:MgCl2

MgCl2 Protocol

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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

To make 150 mL of 500 mM MgCl₂

Calculations

• [math]\displaystyle{ 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} }[/math]

Protocol

1. Using digital scale, place 7.14 g MgCl₂ powder into weigh boat (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)
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 (note: the dissolving of MgCl₂ with H₂O is an exothermic reaction - you may notice the solution fizz a bit when adding water to the powder. Just don't stand over it and inhale, as a general rule)
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.