Difference between revisions of "HighPoint/CannonLab:Buffer and Osmolyte Solutions"

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(pH 7 buffer, 10 mM Phosphate, 50 mM NaCl)
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Required Stock Solutions
Required Stock Solutions
* 1 M dibasic potassium phosphate
* 1 M K<sub>2</sub>HPO<sub>4</sub> (dibasic potassium phosphate)
* 1 M monobasic potassium phosphate
* 1 M KH<sub>2</sub>PO<sub>4</sub> (monobasic potassium phosphate)
* 2 M sodium chloride
* 2 M NaCl (sodium chloride)
To prepare 100 mL
To prepare 100 mL
* 0.490 mL dibasic
* 0.490 mL K<sub>2</sub>HPO<sub>4</sub>
* 0.510 mL monobasic
* 0.510 mL KH<sub>2</sub>PO<sub>4</sub>
* 2.50 mL sodium chloride
* 2.50 mL NaCl
* 96.5 mL H<sub>2</sub>O

Revision as of 10:14, 28 February 2012

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Preparing Buffers

Always wear gloves to avoid contamination of your solutions with bacteria!

Stock Solutions

  1. Prepare stock solutions of buffer components (typically 1 M)
  2. Rinse clean storage bottle and filter flask an extra time
    • Use type I, 18 MΩ purified water
    • Drain and use your best aseptic technique from this point on
  3. Filter stock solutions through 0.2 μm filter
  4. Store in bottle for future use
    • Keep the bottle closed as much as possible
    • Always wear gloves and use clean instruments for removing aliquots
    • This will extend the life of your stock solution before bacteria begin to grow in it


Nalgene Filter Assembly
Filter Flask
  • The filtration assembly is put together as in the image on the left
    1. Place a 45 mm diameter, 0.2 μm pore size filter between the top and bottom halves
    2. Close with the metal clamp
    3. Place the entire assembly onto the mouth of a filter flask
    4. Attach the side arm to an aspirator
    5. Fill the reservoir with the solution to be filtered
  • Repeat step 5 until the entire solution is filtered
  • If the speed of filtration reduces drastically, consider replacing the filter membrane

General rules for solution prep

Adjusting pH

Useful Recipes

1 M K2HPO4

1 M KH2PO4

1 M NaAcetate

1 M Acetic Acid

pH 7 buffer, 10 mM Phosphate, 50 mM NaCl

Required Stock Solutions

  • 1 M K2HPO4 (dibasic potassium phosphate)
  • 1 M KH2PO4 (monobasic potassium phosphate)
  • 2 M NaCl (sodium chloride)

To prepare 100 mL

  • 0.490 mL K2HPO4
  • 0.510 mL KH2PO4
  • 2.50 mL NaCl
  • 96.5 mL H2O