Sodium cacodylate is a common biological buffer; it has a good buffering capacity in the range of pH 5.0–7.4, so its role in the DNA isolation solution is to maintain pH. Cacodylate is often used instead of the phosphate buffer in the applications where it is undesirable to have phosphates introduced into the sample.

Definition: A buffer solution in which the pH (6.4–7.4) is maintained by an cacodylic acid– sodium cacodylate [Na(CH3)2 AsO2] equilibrium.

Sodium Cacodylate is a colorless to light yellow crystalline solid or powder with a slight garlic odor. It is an organic Arsenic compound which is used as a herbicide and a medication in animals.

Basically, make 0.2 M cacodylic acid and 0.2 M NaOH. Add 0.2 M NaOH to 0.2 M cacodylic acid to desired pH. Adjust 50 ml of 0.2M cacodylic acid to desired pH with 0.2M NaOH. Dilute to 100 ml with ddH2 or dilute 1:1 with fixative.

5.8 Step 8: TEM preparation Cells are fixed for 1 h using freshly prepared 0.1 M cacodylate buffer (pH 7.3) containing 3% glutaraldehyde and 2% paraformaldehyde.

Osmolality: The osmotic effects exerted by the fixative are again more important at the ultrastructural level than at the level of the light microscope because it is the phospholipid membranes that are easily damaged by excessively hypotonic or hypertonic solutions, but osmolality does have some relevance in routine …

Prepare stock solutions of 0.2 M mono- and disodium phosphate in 8.5% salt solutions and dilute 1:10 for preparation of 0.02 M phosphate saline buffer.

Cacodylic Acid is an organic Arsenic compound. It is a colorless to white, odorless, crystalline (sand-like) solid that is used as a herbicide and soil sterilant. It is also used in chemical warfare and in timber thinning.

Cacodylic acid/sodium cacodylate is a buffering agent in the preparation and fixation of biological samples for electron microscopy.

To prepare 50mM phosphate buffer with 7.0pH:

1. Prepare 800 mL of distilled water in a suitable container.
2. Add 7.744 g of Na2HPO4•7H2O to the solution.
3. Add 2.913 g of NaH2PO4•H2O to the solution.
4. Adjust solution to final desired pH using HCl or NaOH.
5. Add distilled water until volume is 1 L.

Phosphate Buffer pH 6.8, 0.2 M Mixed: Dissolve 13.872 g of potassium dihydrogen phosphate and 35.084 g of disodium hydrogen phosphate in sufficient water to produce 1000 ml. Store in a cold place.

Buffer Solution Examples Blood – contains a bicarbonate buffer system Tris buffer Phosphate buffer

Calculate the pH for Basic (Alkaline) Buffer Solutions. Multiply the volume (in liters) of the weak base by its concentration (in moles/liter). This gives you the total number of base molecules that will be in the final buffer solution.

To calculate the specific pH of a given buffer, you need to use the Henderson-Hasselbalch equation for acidic buffers: pH = pKa + log10([A-]/[HA]), where Ka is the dissociation constant for the weak acid, [A-] is the concentration of conjugate base and [HA] is the concentration of the weak acid.

A basic buffer is made from a solution containing a weak base and one of its salts. The most common example is a solution of ammonium chloride (salt of a weak base) and ammonia solution (weak base).