Fixatives

In this section:

MEMFA

Bouin’s Fixative

Dent's Fix (Methanol/DMSO)

Paraformaldehyde(PFA), 20%

PTw Containing 4% Paraformaldehyde

MEMFA (MOPS/EGTA/Magnesium Sulfate/Formaldehyde Buffer)

	1X	10X	for 1 L 10X
MOPS (pH 7.4)	0.1 M	1.0 M	209.27 g
EGTA	2 mM	20 mM	7.608 g
MgSO4	1 mM	10 mM	2.46 g
Formaldehyde	3.7%

• Prepare a 10 X solution without the formaldehyde for storage. Add fresh formaldehyde(1/10 volume of standard 30% stock) prior to use. The solution will turn yellow with age and when autoclaved.

Bouin’s Fixative

For 50 ml: 35 ml Piric acid 12.5 ml Formaldehyde 2.5 ml glacial acetic acid Adjust volume, store at RT.

Dent's Fix (Methanol/DMSO)

4 volumes methanol

1 volume DMSO

Paraformaldehyde(PFA), 20%

Measure 4g of Paraformaldehyde in the hood then add to 100 mls of pre-heated PBS.

Heat to around 62-64C.

Once dissolved aliquot 20 mls per tube and store at -20C.

PTw Containing 4% Paraformaldehyde

1 volume of 20% paraformaldehyde

4 volumes of PTw

Note: To made 20% paraformaldehyde in water, neutralize the cloudy solution with NaOH and then heat at 65 deg C, with shaking, until clear, Store at -20 dec C.

PTw

1X PBS(phosphate buffered saline)

0.1% Tween-20