thumb|Person performing a chemical test, 1940

In chemistry, a chemical test is a qualitative or quantitative procedure designed to identify, quantify, or characterise a chemical compound or chemical group.

Purposes

Chemical testing might have a variety of purposes, such as to:

  • Determine if, or verify that, the requirements of a specification, regulation, or contract are met
  • Decide if a new product development program is on track: Demonstrate proof of concept
  • Demonstrate the utility of a proposed patent
  • Determine the interactions of a sample with other known substances
  • Determine the composition of a sample
  • Provide standard data for other scientific, medical, and Quality assurance functions
  • Validate suitability for end-use
  • Provide a basis for Technical communication
  • Provide a technical means of comparison of several options
  • Provide evidence in legal proceedings

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Biochemical tests

  • Clinistrips quantitatively test for sugar in urine
  • The Kastle-Meyer test tests for the presence of hemoglobin
  • Salicylate testing is a category of drug testing that is focused on detecting salicylates such as acetylsalicylic acid for either biochemical or medical purposes.
  • The Phadebas test tests for the presence of saliva for forensic purposes
  • Iodine solution tests for starch
  • The Van Slyke determination tests for specific amino acids
  • The Zimmermann test tests for ketosteroids
  • Seliwanoff's test differentiates between aldose and ketose sugars
  • Test for lipids: add ethanol to sample, then shake; add water to the solution, and shake again. If fat is present, the product turns milky white.
  • The Sakaguchi test detects the presence of arginine in protein
  • The Hopkins–Cole reaction tests for the presence of tryptophan in proteins
  • The nitroprusside reaction tests for the presence of free thiol groups of cysteine in proteins
  • The Sullivan reaction tests for the presence of cysteine and cystine in proteins
  • The Acree–Rosenheim reaction tests for the presence of tryptophan in proteins
  • The Pauly reaction tests for the presence of tyrosine or histidine in proteins
  • Heller's test tests for the presence of albumin in urine
  • Gmelin's test tests for the presence of bile pigments in urine
  • Hay's test tests for the presence of bile pigments in urine

Reducing sugars

  • Barfoed's test tests for reducing polysacchorides or disaccharides
  • Benedict's reagent tests for reducing sugars or aldehydes
  • Fehling's solution tests for reducing sugars or aldehydes, similar to Benedict's reagent
  • Molisch's test tests for carbohydrates
  • Nylander's test tests for reducing sugars
  • Rapid furfural test distinguishes between glucose and fructose

Proteins and polypeptides

  • The bicinchoninic acid assay tests for proteins
  • The Biuret test tests for proteins and polypeptides
  • Bradford protein assay measures protein quantitatively
  • The Phadebas amylase test determines alpha-amylase activity

Organic tests

  • The carbylamine reaction tests for primary amines
  • The esterification reaction tests for the presence of alcohol and/or carboxylic acids
  • The Griess test tests for organic nitrite compounds
  • The 2,4-dinitrophenylhydrazine tests for carbonyl compounds
  • The iodoform reaction tests for the presence of methyl ketones, or compounds which can be oxidized to methyl ketones
  • The Schiff test detects aldehydes
  • Tollens' reagent tests for aldehydes (known as the silver mirror test)
  • The Zeisel determination tests for the presence of esters or ethers
  • Lucas' reagent is used to distinguish between primary, secondary and tertiary alcohols.
  • The bromine test is used to test for the presence of unsaturation and phenols.

Inorganic tests

  • Barium chloride tests for sulfates
  • Acidified silver nitrate solution tests for halide ions
  • The Beilstein test tests for halides qualitatively
  • The bead test tests for certain metals
  • The Carius halogen method measures halides quantitatively.
  • Chemical tests for cyanide test for the presence of cyanide, CN<sup>−</sup>
  • Copper sulfate tests for the presence of water
  • Flame tests test for metals
  • The Gilman test tests for the presence of a Grignard reagent
  • The Kjeldahl method quantitatively determines the presence of nitrogen
  • Nessler's reagent tests for the presence of ammonia
  • Ninhydrin tests for ammonia or primary amines
  • Phosphate tests test for phosphate
  • The sodium fusion test tests for the presence of nitrogen, sulfur, and halides in a sample
  • The Zerewitinoff determination tests for any acidic hydrogen
  • The Oddy test tests for acid, aldehydes, and sulfides
  • Gunzberg's test tests for the presence of hydrochloric acid
  • Kelling's test tests for the presence of lactic acid

See also

  • Independent test organization
  • Medical test
  • Test method

References