Buffered water pH 6.4, pH 6.8, No. 20 pH 7.0, pH 7.2, pH 8.0 for Staining Blood Films

Buffered water pH 6.4, pH 6.8, No. 20 pH 7.0, pH 7.2, pH 8.0 for Staining Blood Film

These reagents can be conveniently prepared from stock phosphate buffer solutions.

Prepartion of Stock of phosphate solution A and Solution B

Stock phosphate solution A

Materials

  • Sodium dihydrogen phosphate, 1-hydrate (NaH2PO4.H2O). . . . . . . . . . 27.6 g
  • Distilled water . . . . . . . . . . . . . . . . . . . . . . to 1 litre

Procedure:

1) Accurately weigh the chemical and transfer it to a 1 litre volumetric flask.

2) Half fill the flask with water, and mix to dissolve the chemical.

3) Make up to the 1 litre mark with distilled water, and mix well.

4) Transfer to a leak-proof bottle. 

5) Label the bottle ‘Stock phosphate solution A’.

6) Store in a cool place or preferably at 2–8 C.

The solution is stable for several months.

Stock phosphate solution B

Materials

  • di-Sodium hydrogen phosphate,anhydrous (Na2HPO4) . . . . . . . . 28.39 g
  • Distilled water . . . . . . . . . . . . . . . . . . . . . . . . . .  . . . . . . . . to 1 litre

Procedure:

  • Prepare as described above for solution A.
  • Label the bottle ‘Stock phosphate solution B’.
  • Store in a cool place or preferably at 2–8 C.

The solution is stable for several months.

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ph-indicator-paper-ph1-14-971Prepare 1 litre pH 6.4, pH 6.8, pH 7.0, pH 7.2, pH 8.0

  • Measure the stock solutions and mix with the distilled water.
  • Check the pH using narrow range pH papers or a pH meter.
  • Store in a leak proof container in a cool place.

PH

Stock Solution A

Stock Solution B

Distilled Water

6.4367.5132.5500
6.8255245500
7.0195305500
7.2140360500
8.026.5473500

 

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Alternative preparation of buffered water reagents using Na2HPO4 and KH2PO4 chemicals

 


To make 1 litre pH 6.8 buffered water:

Material:

  • di-Sodium hydrogen phosphate anhydrous (Na2HPO4). . . . . . . 0.47  gm
  • Potassium di-hydrogen phosphate anhydrous (KH2PO4). . . . . 0.46 gm
  • Distilled water . . . . . . . . . .  . . . . . . . . . . . . . . . . . . . . . . to 1 litre

Procedure:

1) Weigh the chemicals and dissolve completely in the water.

2) Check the pH.

3) Store in a leak proof labelled container in a cool place.

—————————–

To make 1 litre pH 7.0 buffered water:

Materials:

  • di-Sodium hydrogen phosphate anhydrous (Na2HPO4) . . . . . . . 0.58 gm
  • Potassium di-hydrogen phosphate anhydrous (KH2PO4). . . . . 0.35 gm
  • Distilled water . . . . . . . . . . . . . . . . . . . to 1 litre

Procedure:

1) Weigh the chemicals and dissolve completely  in the water.

2) Check the pH.

3) Store in a leak proof labelled container in a cool place.

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