Acid Alcohol


Acid alcohol is a differentiation reagent. It is used in various staining methods, most often in regressive staining with hematoxylin-eosin (HE) and provides excellent differentiation between nuclear and non-nuclear structures. Differentiation removes dyes from the cytoplasm while the nucleus remains stained.

This occurs because the nuclear dye binds more strongly to the nucleus than to the cytoplasm. Regardless of the medium in which the sample is fixed, acid alcohol provides satisfactory results. The amount of time spent on differentiation using acid alcohol is always the same regardless of the fixative used to fix the analyzed sample.

Product Description

ACID ALCOHOL: Acid alcohol solution used for differentiation during regressive staining consisting of an optimal ratio of hydrochloric acid, ethanol and water.

Product use

  • Acid alcohol is used for section differentiation as part of regressive staining methods.
  • Acid alcohol is used for monochromatic and polychromatic staining methods.
  • One of the commonly used staining methods with acid alcohol is the hematoxylin and eosin method.
  • The detailed procedure for hematoxylin-eosin staining is described in the BioGnost Instructions for Use for hematoxylins used in the progressive staining method (G3, H, ML).


Acid alcohol is an acidic solution that can be used to differentiate between basic and cationic dyes. Due to the higher affinity for the dye (aluminium-haematein complex) towards the nucleus, the acid alcohol will discolour the cytoplasm.


The time periods of the staining procedures are not standardized. The intensity of staining depends on the period of immersion in the dye. Actual staining protocol depends on personal requests and laboratory standard operating procedures.

Sample preparation and diagnosis

Use only appropriate instruments to collect and prepare samples. Process the samples with modern technology and mark them clearly. Follow the manufacturer’s instructions for handling. To avoid errors, the staining procedure and diagnosis should only be performed by authorized and qualified personnel.

Use only a microscope in accordance with medical diagnostic laboratory standards. To avoid a mistake result, positive and negative verification is recommended before application.

Safety at work and environmental protection

Handle the product in accordance with the regulations for safety at work and environmental protection. Used solutions and obsolete solutions must be disposed of as special waste in accordance with national guidelines. The chemicals used in this procedure could pose a hazard to human health.

Tried tissue samples are potentially infectious. Safety measures necessary to protect human health must be taken in accordance with good laboratory practice. Act in accordance with the signs and warnings printed on the product label, as well as in the BioGnost material safety data sheet.

Storage, stability and expiration date

Store Acid Alcohol in a tightly closed original container at a temperature of +15 to +25 °C. Do not store in cold places, do not freeze and avoid exposure to direct sunlight. The manufacturing date and expiration date are printed on the product label.

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