Chemical test

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

Person performing a chemical test, 1940

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

Biochemical tests

• 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 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⁻
• 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

1. Niederl, J. B.; Baum, H.; McCoy, J. S.; Kuck, J. A. (1940). "Micro-Carius Halogen and Sulphur Determination". Industrial & Engineering Chemistry Analytical Edition. 12 (7): 428–431. doi:10.1021/ac50147a022. ISSN 0096-4484.