Formalin Solution (10%,
unbuffered):
Formaldehyde (37-40%) ------------- ----10 ml
Distilled water --------------------------- 90 ml
Mix well.
Formalin Solution (20%,
unbuffered):
Formaldehyde (37-40%) ----------------- 20 ml
Distilled water --------------------------- 80 ml
Formalin Solution (10%, buffered neutral):
Formaldehyde (37-40%) ----------------- 100 ml
Distilled water --------------------------- 900 ml
NaH2PO4 ---------------------------------- 4.0 g
Na2HPO4 (anhydrous) ------------------- 6.5 g
Mix to dissolve.
Formalin Solution (20%,
buffered neutral):
Formaldehyde (37-40%) ---------------- 200 ml
Distilled water -------------------------- 800 ml
NaH2PO4 --------------------------------- 4.0 g
Na2HPO4 (anhydrous) ------------------ 6.5 g
Mix to dissolve.
Formalin-Acetic Acid
Solution:
Formaldehyde (37-40%) ---------------- 10 ml
Distilled water --------------------------- 90 ml
Glacial acetic acid ----------------------- 5 ml
Mix well.
Formalin-Alcoholic
Solution:
Formaldehyde (37-40%) --------------- 10 ml
Ethanol (80%) -------------------------- 90 ml
Picric acid (saturated) ------------------- 75 ml
Formaldehyde (37-40%) ------------------ 25 ml
Glacial acetic acid ------------------------- 5 ml
Mix well. For routine surgical material, especially for preserving soft and delicate structures such as brain tissues.
Ethanol (absolute) ----------------------- 60 ml
Chloroform ------------------------------- 30 ml
Glacial acetic acid ----------------------- 10 ml
Mix well.
Note: Used for fixation of DNA, RNA, Nissl granules and glycogen.
Mercuric chloride ---------------------- 5 g
Potassium dichromate ---------------- 2.5 g
Distilled water ------------------------- 100 ml
Heat - cool - filter in brown bottle. Add 5 ml formaldehyde just before use. Wash in running tap water for 24 hours before dehydration.
Note: Used for blood forming organs such as bone marrow, liver and spleen.
Stock
Solution A:
Mercuric chloride ----------------------- 4.5 g
Trichloracetic acid ---------------------- 2 g
Distilled water --------------------------- 80 ml
Stock Solution B:
Glacial acetic acid ---------------------- 4 ml
Formaldehyde (37-40%) ---------------- 20 ml
Mix Solution A and B. For hard tissues such as inner ear with excellent penetration and little shrinkage.
Mercuric chloride ---------------------- 5 g
Potassium dichromate ---------------- 2.5 g
Distilled water ------------------------- 100 ml
Heat - cool - filter in brown bottle. Add 5 ml of glacial acetic
acid just before use. Wash fixed tissue in running tap water for 24
hours before dehydration. Never use metal forceps or metal container
when handling tissues fixed in Zenker Solution.
Note: Used for bloody specimens such as spleen as well as connective tissues.
Zinc Fixative:
0.1M Tris Buffer, pH 7.4:
Tris Base ----------------------------- 12.1 g (TRIZMA)
1N HCL ------------------------------- 81.5 ml
Distilled water ----------------------- 900 ml
Zinc Fixative:
Calcium Acetate
---------------------- 0.5 g
Zinc Acetate --------------------------- 5.0 g
Zinc Chloride -------------------------- 5.0 g
0.1M Tris Buffer made above ------- 1000 ml
Mix to dissolve. The final pH will be approximately 6.5-7.0. Do not
readjust the pH, as this will cause the zinc to come out of
solution. Store Zinc Fixative at room temperature. Fix tissues for
24 to 48 hours.
4% Paraformaldehyde in 0.1M Phosphate Buffer
0.2M
Phosphate Buffer (PB), pH7.4:
Na2HPO4 -------------------- 21.8 g
NaH2PO4 -------------------- 6.4 g
Distilled water ------------- 1000 ml
0.1M
Phosphate Buffer, pH7.4:
0.2M PB --------------------- 500 ml
Distilled water -------------- 500 ml
4% Paraformaldehyde in 0.1M Phosphate
Buffer:
Paraformaldehyde ------------------- 40 g
0.1M Phosphate buffer ------------ 1000 ml
Heat
to 60-65 ºC while stirring. Add a few drops of 1N NaOH until
solution clear. Continue to stir to dissolve. Cool the solution and
filter.
Note: This solution is often used for animal perfusion.
4% Paraformaldehyde-1%
Glutaraldehyde in 0.1M Phosphate Buffer
0.2M
Phosphate Buffer (PB), pH7.4:
Na2HPO4 -------------------- 21.8 g
NaH2PO4 -------------------- 6.4 g
Distilled water ------------- 1000 ml
0.1M
Phosphate Buffer, pH7.4:
0.2M PB ---------------------- 500 ml
Distilled water -------------- 500 ml
4% Paraformaldehyde-1% Glutaraldehyde
in 0.1M PB:
Paraformaldehyde --------------- 40 g
0.1M Phosphate buffer -------- 1000 ml
Heat
to 60-65 ºC while stirring. Add a few drops of 1N NaOH until
solution clear. Continue to stir to dissolve. Cool the solution and
filter. Add 20 ml of 50% glutaraldehyde and mix well.
Note: This solution is often used for
animal perfusion, especially for electron microscopy.