What is "assay"

Assay \As*say"\, v. t. [imp. & p. p. Assayed; p. pr. & vb. n. Assaying.] [OF. asaier, essaier, F. essayer, fr. essai. See Assay, n., Essay, v.]

1. To try; to attempt; to apply. [Obs. or Archaic]

   To-night let us assay our plot.
   --Shak.

   Soft words to his fierce passion she assayed.
   --Milton.

2. To affect. [Obs.]

   When the heart is ill assayed.
   --Spenser.

3. To try tasting, as food or drink. [Obs.]

4. To subject, as an ore, alloy, or other metallic compound, to chemical or metallurgical examination, in order to determine the amount of a particular metal contained in it, or to ascertain its composition.

Assay \As*say"\, n. [OF. asai, essai, trial, F. essa. See Essay, n.]

1. Trial; attempt; essay. [Obs.]
   --Chaucer.

   I am withal persuaded that it may prove much more easy in the assay than it now seems at distance.
   --Milton.

2. Examination and determination; test; as, an assay of bread or wine. [Obs.]

   This can not be, by no assay of reason.
   --Shak.

3. Trial by danger or by affliction; adventure; risk; hardship; state of being tried. [Obs.]

   Through many hard assays which did betide.
   --Spenser.

4. Tested purity or value. [Obs.]

   With gold and pearl of rich assay.
   --Spenser.

5. (Metallurgy) The act or process of ascertaining the proportion of a particular metal in an ore or alloy; especially, the determination of the proportion of gold or silver in bullion or coin.

6. The alloy or metal to be assayed.
   --Ure.

   Usage: Assay and essay are radically the same word; but modern usage has appropriated assay chiefly to experiments in metallurgy, and essay to intellectual and bodily efforts. See Essay.

   Note: Assay is used adjectively or as the first part of a compound; as, assay balance, assay furnace.

   Assay master, an officer who assays or tests gold or silver coin or bullion.

   Assay ton, a weight of 29,166 2/3 grams.

Assay \As*say"\, v. i. To attempt, try, or endeavor. [Archaic. In this sense essay is now commonly used.]

She thrice assayed to speak.
--Dryden.

c.1300, "to try, endeavor, strive; test the quality of," from Anglo-French assaier, from assai (n.), from Old French essai "trial" (see essay).

"trial, test of quality, test of character," mid-14c., from Anglo-French assai (see assay (v.)). Meaning "analysis" is from late 14c.

n. 1 trial, attempt, essay. 2 Examination and determination; test. 3 The qualitative or quantitative chemical analysis of something. 4 Trial by danger or by affliction; adventure; risk; hardship; state of being tried. 5 Tested purity or value. 6 The act or process of ascertaining the proportion of a particular metal in an ore or alloy; especially, the determination of the proportion of gold or silver in bullion or coin. 7 The alloy or metal to be assayed. vb. 1 (context transitive English) To attempt (something). (from 14^thc.) 2 (context archaic intransitive English) To try, attempt ((term: to) do something). (14^th-19^thc.) 3 (context transitive English) To analyze or estimate the composition or value of (a metal, ore etc.). (from 15^thc.) 4 (context obsolete transitive English) To test the abilities of (someone) in combat; to fight. (15^th-17^thc.) 5 To affect. 6 To try tasting, as food or drink.

1. n. an appraisal of the state of affairs; "they made an assay of the contents"; "a check on its dependability under stress" [syn: check]

2. a substance that is undergoing an analysis of its components

3. a written report of the results of an analysis of the composition of some substance

4. a quantitative or qualitative test of a substance (especially an ore or a drug) to determine its components; frequently used to test for the presence or concentration of infectious agents or antibodies etc.

5. v. analyze (chemical substances)

6. make an effort or attempt; "He tried to shake off his fears"; "The infant had essayed a few wobbly steps"; "The police attempted to stop the thief"; "He sought to improve himself"; "She always seeks to do good in the world" [syn: try, seek, attempt, essay]

An assay is an investigative (analytic) procedure in laboratory medicine, pharmacology, environmental biology and molecular biology for qualitatively assessing or quantitatively measuring the presence or amount or the functional activity of a target entity (the analyte). The analyte can be a drug or biochemical substance or a cell in an organism or organic sample. The measured entity is generally called the analyte, or the measurand or the target of the assay. The assay usually aims to measure an intensive property of the analyte and express it in the relevant measurement unit (e.g. molarity, density, functional activity in enzyme international units, degree of some effect in comparison to a standard, etc.).

If the assay involves addition of exogenous reactants (the reagents) then their quantities are kept fixed (or in excess) so that the quantity (and quality) of the target is the only limiting factor for the reaction/assay process, and the difference in the assay outcome is used to deduce the unknown quality or quantity of the target in question. Some assays (e.g., biochemical assays) may be similar to or have overlap with chemical analysis and titration. But generally, assays involve biological material or phenomena which tend to be intrinsically more complex either in composition or in behavior or both. Thus reading of an assay may be quite noisy and may involve greater difficulties in interpretation than an accurate chemical titration. On the other hand, older generation qualitative assays, especially bioassays, may be much more gross and less quantitative (e.g., counting death or dysfunction of an organism or cells in a population, or some descriptive change in some body part of a group of animals).

Assays have become a routine part of modern medical, environmental, pharmaceutical, forensic and many other businesses at various scales from industrial to curbside or field level. Those assays that are very highly commercially demanded have been well investigated in research and development sectors of professional industries, undergone generations of development and sophistication, and become copyrighted intellectual properties via highly competitive process patenting. Such industrial scale assays as these are often done in well equipped laboratories and with automated organization of the procedure—from ordering an assay to pre-analytic sample processing (sample collection, necessary manipulations e.g. spinning for separation or other processes, aliquoting if necessary, storage, retrieval, pipetting/aspiration etc.). Analytes are generally tested in high throughput AutoAnalyzers, and the results are verified and automatically returned to ordering service providers and end users. These are made possible through use of advanced Laboratory informatics system that interfaces with multiple computer terminals with end users, central servers, the physical autoanalyser instruments, and other automata.