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Last updated: December 15, 2018

What Does Assay Mean?

Assay is a procedure for the examination or determination of quality or strength of a substance. It is the analysis of the amount of metal in an ore, or the determination of the amount of purities in a precious metal. An assay procedure is generally employed to evaluate an intensive property of the measured entity, called "analyte". It is expressed in a relevant measurement unit like density, molarity, etc.

Assay is being used as a routine examination procedure in modern environmental, pharmaceutical, chemical, and many other industries at different scales. Industrial-scale assays are frequently performed in fully equipped laboratories and with an automated and computer control procedure.


Corrosionpedia Explains Assay

An assay is an investigation procedure for the determination of purity/quality of a metal, substance, or sample. It is widely used in different scales in various industries—specifically medical, chemical, and environmental industries. Now assay has become a part of the routine procedure of investigation, both qualitatively and quantitatively in these industries. Assay is done combined with both pre and post-analytic procedures.

Assay types are varied and depend on many things. Assays can be single target assays or multiplex assays, depending on how many targets or analytes are measured. Assays can be typified into four classes when considering the quality of the results produced:

  • Qualitative assay - it produces qualitative gradation but not an exact quantity. It gives a pass or fail.
  • Semi-quantitative assays - it produces approximate gradation but not an exact number for the quantity of the substance.
  • Quantitative assays - it gives precise and correct numeric quantitative values of the amount of a substance in a sample.
  • Functional assay - it tries to quantitatively measure the functioning of an active substance, rather than just its quantity.

In the pharmaceutical industry, the safety of workers handling solid intermediaries is assessed through in vitro assays. In petro-chemistry, crude oil assay is used. It gives a detailed hydrocarbon analysis data for refinery engineers, oil businessmen, and producers. It helps to determine the suitability of crude oil feedstock to a particular refinery.


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