In chemistry, a chemical test is a

qualitative Qualitative descriptions or distinctions are based on some quality or characteristic rather than on some quantity or measured value. Qualitative may also refer to: *Qualitative property, a property that can be observed but not measured numericall ...

quantitative Quantitative may refer to: * Quantitative research, scientific investigation of quantitative properties * Quantitative analysis (disambiguation) * Quantitative verse, a metrical system in poetry * Statistics, also known as quantitative analysis ...

procedure designed to identify, quantify, or characterise a

chemical compound A chemical compound is a chemical substance composed of many identical molecules (or molecular entities) containing atoms from more than one chemical element held together by chemical bonds. A molecule consisting of atoms of only one ele ...

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 A specification often refers to a set of documented requirements to be satisfied by a material, design, product, or service. A specification is often a type of technical standard. There are different types of technical or engineering specificat ...

regulation Regulation is the management of complex systems according to a set of rules and trends. In systems theory, these types of rules exist in various fields of biology Biology is the scientific study of life. It is a natural science with a ...

, or

contract A contract is a legally enforceable agreement between two or more parties that creates, defines, and governs mutual rights and obligations between them. A contract typically involves the transfer of goods, services, money, or a promise to ...

are met * Decide if a new product development program is on track: Demonstrate

proof of concept Proof of concept (POC or PoC), also known as proof of principle, is a realization of a certain method or idea in order to demonstrate its feasibility, or a demonstration in principle with the aim of verifying that some concept or theory has prac ...

* Demonstrate the utility of a proposed

patent A patent is a type of intellectual property that gives its owner the legal right to exclude others from making, using, or selling an invention for a limited period of time in exchange for publishing an sufficiency of disclosure, enabling disclo ...

* Determine the interactions of a sample with other known substances * Determine the composition of a sample * Provide standard

data In the pursuit of knowledge, data (; ) is a collection of discrete values that convey information, describing quantity, quality, fact, statistics, other basic units of meaning, or simply sequences of symbols that may be further interpret ...

for other scientific, medical, and Quality assurance functions * Validate suitability for end-use * Provide a basis for

Technical communication Technical communication is used to convey scientific, engineering, or other technical information. Individuals in a variety of contexts and with varied professional credentials engage in technical communication. Some individuals are designated as ...

* Provide a technical means of comparison of several options * Provide

evidence Evidence for a proposition is what supports this proposition. It is usually understood as an indication that the supported proposition is true. What role evidence plays and how it is conceived varies from field to field. In epistemology, eviden ...

in legal proceedings

Biochemical tests

* Clinistrips quantitatively test for sugar in

urine Urine is a liquid by-product of metabolism in humans and in many other animals. Urine flows from the kidneys through the ureters to the urinary bladder. Urination results in urine being excreted from the body through the urethra. Cellular ...

* The Kastle-Meyer test tests for the presence of

blood Blood is a body fluid in the circulatory system of humans and other vertebrates that delivers necessary substances such as nutrients and oxygen to the cells, and transports metabolic waste products away from those same cells. Blood in th ...

* 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 Tincture of iodine, iodine tincture, or weak iodine solution is an antiseptic. It is usually 2 to 7% elemental iodine, along with potassium iodide or sodium iodide, dissolved in a mixture of ethanol and water. Tincture solutions are characterized ...

tests for

starch Starch or amylum is a polymeric carbohydrate consisting of numerous glucose units joined by glycosidic bonds. This polysaccharide is produced by most green plants for energy storage. Worldwide, it is the most common carbohydrate in human diets ...

* The Van Slyke determination tests for specific

amino acid Amino acids are organic compounds that contain both amino and carboxylic acid functional groups. Although hundreds of amino acids exist in nature, by far the most important are the alpha-amino acids, which comprise proteins. Only 22 alpha ...

s * The Zimmermann test tests for ketosteroids * Seliwanoff's test differentiates between aldose and ketose sugars * Test for lipids: add

ethanol Ethanol (abbr. EtOH; also called ethyl alcohol, grain alcohol, drinking alcohol, or simply alcohol) is an organic compound. It is an alcohol with the chemical formula . Its formula can be also written as or (an ethyl group linked to a h ...

to sample, then shake; add water to the solution, and shake again. If fat is present, the product turns milky white. *The

Sakaguchi test The Sakaguchi test is a chemical test used to detect presence of arginine in proteins. It is named after the Japanese food scientist and organic chemist, Shoyo Sakaguchi (1900–1995) who described the test in 1925. The Sakaguchi reagent used ...

detects the presence of

arginine Arginine is the amino acid with the formula (H2N)(HN)CN(H)(CH2)3CH(NH2)CO2H. The molecule features a guanidino group appended to a standard amino acid framework. At physiological pH, the carboxylic acid is deprotonated (−CO2−) and both the a ...

in protein *The Hopkins–Cole reaction tests for the presence of

tryptophan Tryptophan (symbol Trp or W) is an α-amino acid that is used in the biosynthesis of proteins. Tryptophan contains an α-amino group, an α-carboxylic acid group, and a side chain indole, making it a polar molecule with a non-polar aromati ...

in proteins *The nitroprusside reaction tests for the presence of free

thiol In organic chemistry, a thiol (; ), or thiol derivative, is any organosulfur compound of the form , where R represents an alkyl or other organic substituent. The functional group itself is referred to as either a thiol group or a sulfhydryl gro ...

groups of

cysteine Cysteine (symbol Cys or C; ) is a semiessential proteinogenic amino acid with the formula . The thiol side chain in cysteine often participates in enzymatic reactions as a nucleophile. When present as a deprotonated catalytic residue, s ...

in proteins *The

Sullivan reaction Sullivan may refer to: People Characters * Chloe Sullivan, from the television series ''Smallville'' * Colin Sullivan, a character in the film ''The Departed'', played by Matt Damon * Harry Sullivan (''Doctor Who''), from the British science f ...

tests for the presence of

and

cystine Cystine is the oxidized derivative of the amino acid cysteine and has the formula (SCH2CH(NH2)CO2H)2. It is a white solid that is poorly soluble in water. As a residue in proteins, cystine serves two functions: a site of redox reactions and a m ...

in proteins *The

Acree–Rosenheim reaction The Acree-Rosenheim reaction is a chemical test used for detecting the presence of tryptophan in proteins. A protein mixture is mixed with formaldehyde. Concentrated sulfuric acid is added to form two layers. A purple ring appears between the two la ...

tests for the presence of

in proteins *The

Pauly reaction The Pauly reaction is a chemical test used for detecting the presence of tyrosine or histidine in proteins. It is named after German chemist Hermann Pauly, who first described the reaction. When proteins containing either tyrosine or histidine are ...

tests for the presence of

tyrosine -Tyrosine or tyrosine (symbol Tyr or Y) or 4-hydroxyphenylalanine is one of the 20 standard amino acids that are used by cells to synthesize proteins. It is a non-essential amino acid with a polar side group. The word "tyrosine" is from the Gr ...

histidine Histidine (symbol His or H) is an essential amino acid that is used in the biosynthesis of proteins. It contains an α-amino group (which is in the protonated –NH3+ form under biological conditions), a carboxylic acid group (which is in the ...

in proteins *

Heller's test Heller's test is a chemical test that shows that strong acids cause the denaturation of precipitated proteins. Concentrated nitric acid is added to a protein solution from the side of the test tube to form two layers. A white ring appears between t ...

tests for the presence of

albumin Albumin is a family of globular proteins, the most common of which are the serum albumins. All the proteins of the albumin family are water-soluble, moderately soluble in concentrated salt solutions, and experience heat denaturation. Albumins ...

* 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

polysaccharide Polysaccharides (), or polycarbohydrates, are the most abundant carbohydrates found in food. They are long chain polymeric carbohydrates composed of monosaccharide units bound together by glycosidic linkages. This carbohydrate can react with ...

s or

disaccharide A disaccharide (also called a double sugar or ''biose'') is the sugar formed when two monosaccharides are joined by glycosidic linkage. Like monosaccharides, disaccharides are simple sugars soluble in water. Three common examples are sucrose, ...

s * Benedict's reagent tests for reducing sugars or

aldehyde In organic chemistry, an aldehyde () is an organic compound containing a functional group with the structure . The functional group itself (without the "R" side chain) can be referred to as an aldehyde but can also be classified as a formyl group ...

s * Fehling's solution tests for reducing sugars or aldehydes, similar to Benedict's reagent *

Molisch's test Molisch's test is a sensitive chemical test, named after Austrian botanist Hans Molisch, for the presence of carbohydrates, based on the dehydration of the carbohydrate by sulfuric acid or hydrochloric acid to produce an aldehyde, which condense ...

tests for carbohydrates *

Nylander's test Nylander's test is a chemical test used for detecting the presence of reducing sugars. Glucose or fructose reduces bismuth oxynitrate to bismuth under alkaline conditions. When Nylander's reagent, which consists of bismuth nitrate, potassium sodiu ...

tests for reducing sugars *

Rapid furfural test The rapid furfural test is a chemical test used to distinguish between glucose and fructose. The rapid furfural test is similar to Molisch's test but uses concentrated hydrochloric acid instead of concentrated sulfuric acid and the solution is bo ...

distinguishes between

glucose Glucose is a simple sugar with the molecular formula . Glucose is overall the most abundant monosaccharide, a subcategory of carbohydrates. Glucose is mainly made by plants and most algae during photosynthesis from water and carbon dioxide, usi ...

and

fructose Fructose, or fruit sugar, is a ketonic simple sugar found in many plants, where it is often bonded to glucose to form the disaccharide sucrose. It is one of the three dietary monosaccharides, along with glucose and galactose, that are absorb ...

Proteins and polypeptides

* The

bicinchoninic acid assay The bicinchoninic acid assay (BCA assay), also known as the Smith assay, after its inventor, Paul K. Smith at the Pierce Chemical Company, now part of Thermo Fisher Scientific, is a biochemical assay for determining the total concentration of pro ...

tests for

protein Proteins are large biomolecules and macromolecules that comprise one or more long chains of amino acid residues. Proteins perform a vast array of functions within organisms, including catalysing metabolic reactions, DNA replication, respon ...

s * The Biuret test tests for

s and

polypeptide Peptides (, ) are short chains of amino acids linked by peptide bonds. Long chains of amino acids are called proteins. Chains of fewer than twenty amino acids are called oligopeptides, and include dipeptides, tripeptides, and tetrapeptides ...

s * Bradford protein assay measures

quantitatively * The Phadebas amylase test determines alpha-amylase activity

Organic tests

* The carbylamine reaction tests for primary

amine In chemistry, amines (, ) are compounds and functional groups that contain a basic nitrogen atom with a lone pair. Amines are formally derivatives of ammonia (), wherein one or more hydrogen atoms have been replaced by a substituent su ...

s * The Griess test tests for organic nitrite compounds * The iodoform reaction tests for the presence of methyl

ketone In organic chemistry, a ketone is a functional group with the structure R–C(=O)–R', where R and R' can be a variety of carbon-containing substituents. Ketones contain a carbonyl group –C(=O)– (which contains a carbon-oxygen double bon ...

s, or compounds which can be oxidized to methyl ketones * The Schiff test detects

s *

Tollens' reagent Tollens' reagent (chemical formula Ag(NH3)2OH) is a chemical reagent used to distinguish between aldehydes and ketones along with some alpha-hydroxy ketones which can tautomerize into aldehydes. The reagent consists of a solution of silver nitr ...

tests for

aldehydes In organic chemistry, an aldehyde () is an organic compound containing a functional group with the structure . The functional group itself (without the "R" side chain) can be referred to as an aldehyde but can also be classified as a formyl grou ...

(known as the silver mirror test) * The Zeisel determination tests for the presence of

ester In chemistry, an ester is a compound derived from an oxoacid (organic or inorganic) in which at least one hydroxyl group () is replaced by an alkoxy group (), as in the substitution reaction of a carboxylic acid and an alcohol. Glycerides ...

s or

ether In organic chemistry, ethers are a class of compounds that contain an ether group—an oxygen atom connected to two alkyl or aryl groups. They have the general formula , where R and R′ represent the alkyl or aryl groups. Ethers can again b ...

s * Lucas' reagent is used to distinguish between

primary Primary or primaries may refer to: Arts, entertainment, and media Music Groups and labels * Primary (band), from Australia * Primary (musician), hip hop musician and record producer from South Korea * Primary Music, Israeli record label Work ...

, secondary and

tertiary Tertiary ( ) is a widely used but obsolete term for the geologic period from 66 million to 2.6 million years ago. The period began with the demise of the non- avian dinosaurs in the Cretaceous–Paleogene extinction event, at the start ...

alcohols. * The bromine test is used to test for the presence of unsaturation and

phenols In organic chemistry, phenols, sometimes called phenolics, are a class of chemical compounds consisting of one or more hydroxyl groups (— O H) bonded directly to an aromatic hydrocarbon group. The simplest is phenol, . Phenolic compounds ...

Inorganic tests

* Barium chloride tests for

sulfate The sulfate or sulphate ion is a polyatomic ion, polyatomic anion with the empirical formula . Salts, acid derivatives, and peroxides of sulfate are widely used in industry. Sulfates occur widely in everyday life. Sulfates are salt (chemistry), ...

s * The

Beilstein test The Beilstein test is a simple qualitative chemical test for organic halides. It was developed by Friedrich Konrad Beilstein. A copper wire is cleaned and heated in a Bunsen burner flame to form a coating of copper(I) oxide. It is then dipped ...

tests for

halide In chemistry, a halide (rarely halogenide) is a binary chemical compound, of which one part is a halogen atom and the other part is an element or radical that is less electronegative (or more electropositive) than the halogen, to make a f ...

s qualitatively * The

bead test The bead test is a traditional part of qualitative inorganic analysis to test for the presence of certain metals. The oldest one is the borax bead test or blister test. It was introduced by Berzelius in 1812.''Materials Handbook: A Concise Desktop ...

tests for certain

metal A metal (from Greek μέταλλον ''métallon'', "mine, quarry, metal") is a material that, when freshly prepared, polished, or fractured, shows a lustrous appearance, and conducts electricity and heat relatively well. Metals are typi ...

s * The Carius halogen method measures

s quantitatively.{{cite journal, last1=Niederl, first1=J. B., last2=Baum, first2=H., last3=McCoy, first3=J. S., last4=Kuck, first4=J. A., title=Micro-Carius Halogen and Sulphur Determination, journal=Industrial & Engineering Chemistry Analytical Edition, volume=12, issue=7, year=1940, pages=428–431, issn=0096-4484, doi=10.1021/ac50147a022 * Chemical tests for cyanide test for the presence of

cyanide Cyanide is a naturally occurring, rapidly acting, toxic chemical that can exist in many different forms. In chemistry, a cyanide () is a chemical compound that contains a functional group. This group, known as the cyano group, consists of ...

, CN⁻ * Copper sulfate tests for the presence of water *

Flame test A flame test is an analytical procedure used in chemistry to detect the presence of certain elements, primarily metal ions, based on each element's characteristic flame emission spectrum (which may be affected by the presence of chloride ...

s test for

s * The Gilman test tests for the presence of a Grignard reagent * The Kjeldahl method quantitatively determines the presence of

nitrogen Nitrogen is the chemical element with the symbol N and atomic number 7. Nitrogen is a nonmetal and the lightest member of group 15 of the periodic table, often called the pnictogens. It is a common element in the universe, estimated at seve ...

* Nessler's reagent tests for the presence of

ammonia Ammonia is an inorganic compound of nitrogen and hydrogen with the formula . A stable binary hydride, and the simplest pnictogen hydride, ammonia is a colourless gas with a distinct pungent smell. Biologically, it is a common nitrogeno ...

* Ninhydrin tests for

or primary

s * Phosphate tests test for

phosphate In chemistry, a phosphate is an anion, salt, functional group or ester derived from a phosphoric acid. It most commonly means orthophosphate, a derivative of orthophosphoric acid . The phosphate or orthophosphate ion is derived from phosph ...

* The

sodium fusion test The sodium fusion test, or Lassaigne's test, is used in elemental analysis for the qualitative determination of the presence of foreign elements, namely halogens, nitrogen, and sulfur, in an organic compound. It was developed by J. L. Lassaigne. T ...

tests for the presence of

sulfur Sulfur (or sulphur in British English) is a chemical element with the symbol S and atomic number 16. It is abundant, multivalent and nonmetallic. Under normal conditions, sulfur atoms form cyclic octatomic molecules with a chemical formul ...

, and

s in a sample * The Zerewitinoff determination tests for any acidic hydrogen * The Oddy test tests for acid, aldehydes, and sulfides *

Gunzberg's test Gunzberg's test is a chemical test used for detecting the presence of hydrochloric acid. Gunzberg's reagent is made by dissolving two grams of phloroglucinol and one gram of vanillin in 100 millilitres of 95% ethanol. Hydrochloric acid catalyses Gun ...

tests for the presence of

hydrochloric acid Hydrochloric acid, also known as muriatic acid, is an aqueous solution of hydrogen chloride. It is a colorless solution with a distinctive pungent smell. It is classified as a strong acid. It is a component of the gastric acid in the dig ...

* Kelling's test tests for the presence of

lactic acid Lactic acid is an organic acid. It has a molecular formula . It is white in the solid state and it is miscible with water. When in the dissolved state, it forms a colorless solution. Production includes both artificial synthesis as well as natur ...

References

Analytical chemistry Measurement

Purposes

Biochemical tests

Reducing sugars

Proteins and polypeptides

Organic tests

Inorganic tests

See also

References