Molisch test

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Definition

Noun: 1. A biochemical test for carbohydrates: The Molisch test is a chemical procedure used to indicate the presence of carbohydrates (like sugars and starches) in a given solution. The test is based on a color change reaction.

Usage

The term "Molisch test" is used specifically in scientific contexts, such as biochemistry, analytical chemistry, and biology laboratories, to name and describe this particular diagnostic procedure.

Examples
  • The presence of a complex carbohydrate was confirmed using the Molisch test.
  • In the laboratory exercise, students performed the Molisch test on various food samples.
  • A positive Molisch test is indicated by the formation of a purple or violet ring at the interface of the liquids.
Advanced Usage
  • The test is named after the Austrian botanist Hans Molisch.
  • It is considered a general test for carbohydrates, as it gives a positive result for a wide range of them, including monosaccharides, disaccharides, and polysaccharides.
Variants and Related Words
  • Molisch reaction (n): Often used interchangeably with "Molisch test" to refer to the chemical reaction itself.
  • Alpha-naphthol test (n): An alternative name for the Molisch test, referring to one of its key reagents.
Synonyms
  • General test for carbohydrates
Related Terms and Concepts
  • Dehydration: The first step of the Molisch test, where concentrated sulfuric acid dehydrates the carbohydrate to form furfural or hydroxymethylfurfural.
  • Condensation: The second step, where these dehydration products condense with alpha-naphthol to form a purple-colored complex.
  • Positive control: A sample known to contain carbohydrates (e.g., glucose solution) used to validate the test procedure.
  • Negative control: A sample known to lack carbohydrates (e.g., pure water) used to ensure the reagents are not contaminated.
Noun
  1. biochemical indicator of the presence of carbohydrates in a solution; if carbohydrates are present a violet ring is formed by reaction with alpha-naphthol in the presence of sulfuric acid

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