A very pink appearance in the last absolute alcohol during dehydration signals which problem?

• A. Water Contamination
• B. Overdehydration
• C. Excess Color
• D. Contaminated Alcohol With Dye

Answer: (A)

Absolute alcohol must be truly anhydrous for proper dehydration. A pink tint in the last absolute alcohol is a signal that water has contaminated the dehydrating solvent. Water in the alcohol changes its properties and can carry residual moisture into the tissue, hindering complete dehydration and affecting downstream steps like clearing and embedding. Replace the alcohol with fresh, dry absolute alcohol and ensure containers are sealed and protected from moisture.

Overdehydration would cause tissue shrinkage and brittleness rather than a pink color. Excess color is a staining issue, not a dehydration indicator. Contaminated alcohol with dye could color the solvent, but the distinct pink seen in the last absolute alcohol is most classically a sign of water contamination.