Which reagents are used for surface decalcification and what is the typical exposure time?

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Multiple Choice

Which reagents are used for surface decalcification and what is the typical exposure time?

Surface decalcification relies on carefully controlled acid exposure to remove mineral content only from the outer part of the tissue, so deeper structures stay intact and staining remains reliable. The standard approach uses mild acids in short contact times—10% nitric acid or 1% hydrochloric acid for about 30 minutes to 1 hour—followed by a thorough wash in cold water to halt the reaction. This brief, surface-focused treatment minimizes over-decalcification and preserves cellular detail for subsequent sectioning and staining. Why not the other options? A strong acid like 6N HCl for 24 hours would over-decalcify and damage tissue morphology. A dehydrating solvent such as 70% ethanol does not remove calcium. A strong oxidizing/bleaching agent like 3% sodium hypochlorite would degrade tissue rather than decalcify it.

Surface decalcification relies on carefully controlled acid exposure to remove mineral content only from the outer part of the tissue, so deeper structures stay intact and staining remains reliable. The standard approach uses mild acids in short contact times—10% nitric acid or 1% hydrochloric acid for about 30 minutes to 1 hour—followed by a thorough wash in cold water to halt the reaction. This brief, surface-focused treatment minimizes over-decalcification and preserves cellular detail for subsequent sectioning and staining.

Why not the other options? A strong acid like 6N HCl for 24 hours would over-decalcify and damage tissue morphology. A dehydrating solvent such as 70% ethanol does not remove calcium. A strong oxidizing/bleaching agent like 3% sodium hypochlorite would degrade tissue rather than decalcify it.

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