Mowry's Colloidal Iron
for Acid Mucosubstances
Materials
- Acetic acid, glacial
- Potassium ferrocyanide, 2% aqueous
- Hydrochloric acid, 2% aqueous
- Müller’s colloidal iron suspension
Working colloidal iron
| Material | Amount | |
|---|---|---|
| Distilled water | 15 | mL |
| Acetic acid, glacial | 5 | mL |
| Colloidal iron suspension | 20 | mL |
pH should be 1.1 – 1.3.
Perls’ solution
| Material | Amount | |
|---|---|---|
| 2% potassium ferrocyanide | 1 | vol |
| 2% hydrochloric acid | 1 | vol |
Tissue Sample
5µ paraffin sections of neutral buffered formalin fixed tissue are suitable. Other fixatives are likely to be satisfactory.
Protocol
- Bring sections to water via xylene and ethanol.
- Rinse with 12% acetic acid for 30 seconds.
- Place in freshly made working colloidal iron for 1 hour.
- Rinse with 12% acetic acid, 4 changes of 3 minutes each.
- Place into freshly made Perls’ solution for 20 minutes.
- Wash in running tap water for 5 minutes.
- Counterstain with Feulgen, PAS or a strictly progressive Hemalum.
- Optionally, dip in aqueous picric acid, then rinse with tap water a few seconds.
- Dehydrate with ethanols.
- Clear with xylene and mount with a resinous medium.
Expected Results
- Acid mucosubstances – blue
- Nuclei – red or blue
- Cytoplasm – yellow or colorless
- Neutral mucosubstances – red, if stained with PAS
Notes
- Step 7 could be replaced with a simple counterstain, such as neutral red or nuclear fast red.
- Although a PAS will allow neutral mucosubstances to be demonstrated red in contrast to the blue of acid mucosubstances, the two are often mixed and the distinction may not be clear.
Safety Note
Prior to handling any chemical, consult the Safety Data Sheet (SDS) for proper handling and safety precautions.
References
- Humason, G. L., (1967)
Animal tissue techniques, Ed. 2
W. H. Freeman and Company, San Francisco, Ca, USA
