1 Shagore

Difference Between Assay And Essay

Assay vs Purity

Substances are hardly found in a pure state. If it is an element, it forms various combinations between them or with other elements in order to exist. Not only elements, molecules and compounds also tend to mix with a large number of other species in nature. Therefore, often all the substances exist as mixtures.


In chemistry, an assay is an analysis carried out to determine the level of impurities a sample has. It is a quantitative determination. In a sample, after identifying the main material present in it, its concentration is measured in an assay. Assay methods normally incorporate accurate and precise analytical methods. There are various types of assays. Depending on the sample to be analyzed and the other requirements, you can choose the most appropriate assay type. Chemical assays are done using techniques like chromatography, titrations, etc.

Assays are done to determine the purity of metals in an ore. One such method is the wet method where the sample is dissolved in an acid to extract the metal. Sometimes a dry method can also be used where the metal is mixed with a substance to reduce the melting point. Then by fluxing, the impurities are removed while leaving the purified metal as a residue. Bioassays are another type of assays carried out to quantify the effect of samples in biological systems. It includes studies of drugs on micro- organisms, virulence studies on human, bioassay of hormones, etc.


Pure means absence of contaminants or other materials, which we do not expect to have in a sample. Purity is some kind of a measurement to indicate how pure the sample is. This measurement can be qualitative or quantitative. If the purity is low, that means there are lots of contaminants. If the purity is high, then the contaminants are low. Pure substance cannot be separated into two or more substances by any mechanical or physical method. Pure substance is, therefore, homogenous. It has a uniform composition throughout the sample. Further, the properties of it are also uniform throughout the sample. Elements are pure substances. An element is a chemical substance that consists of only a single type of atoms, hence they are pure. There are about 118 elements given in the periodic table according to their atomic number. For example, the smallest element is the hydrogen, and silver, gold, platinum are some of the commonly known precious elements. Elements can be subjected to chemical changes to form various compounds; however, elements cannot be further broken down by simple chemical methods. Compounds are the other type of pure substances. Compounds are made up by two or more different chemical elements. Although there are two or more elements joined together when forming a compound, these cannot be separated by any physical means. Rather, they can only be decomposed by chemical means. So this makes a compound a pure substance. Purity can be expressed as a fraction or a percentage.

What is the difference between Assay and Purity?

• Purity is some kind of measurement to indicate how pure the sample is. An assay is an analysis carried out to determine the level of impurities a sample has.

• Assays are quantitative, and purity can be indicated quantitatively or qualitatively.

Cite This Page
"Difference Between Assay and Purity." DifferenceBetween.Com. March 15, 2012. < https://www.differencebetween.com/difference-between-assay-and-vs-purity/ >

Filed Under: ChemistryTagged With: assay, Bioassays, Chemical assays, purity

It is easy to get confused about the difference between literature reviews and essays because these two writing structures can be based on the same research.  However, the main difference is on where the emphasis is placed.

The purpose of an essay is to use what is known about a subject to prove an argument or point of view.  Not all of the knowledge of a topic may be used in an essay, but only what is relevant to the argument.  In an essay, mentioning the people who discovered or developed the knowledge is generally only for referencing purposes.

On the other hand, a literature review is designed to be a critical analysis of all the knowledge that has been discovered about a subject.  Its purpose is to examine all that others have already discovered about the subject and the researchers working on the subject are considered to be key.

At a sentence level, one way to emphasise a particular aspect of a subject is to place that aspect at the beginning of sentences and paragraphs.

In an essay, where the focus is on the knowledge itself, it is put to the front of sentences.  For example:

Playing computer and video games have risen dramatically in popularity.  It is estimated that three billion hours of gaming are played globally each week.  The major reason for this is because players are able to tap into a high level of emotional satisfaction that is difficult to experience in everyday life (McGonigal, 2011).

However, in literature reviews what is considered to be more important are the authors and researchers who found or developed the information.  Therefore they appear at the beginning of sentences.

Jane McGonigal (2011) estimates that three billion hours of gaming are played globally every week.  Her research suggests that the major reason for this is because players are able to tap into a high level of emotional satisfaction that is difficult to experience in everyday life.

This is not to say that both kinds of sentences can be used in both types of writing.  However, the overall trend for essays is to emphasise the information, whereas for literature reviews the trend is to emphasise the authors.

For more on the differences between the structure of essays and the structure of literature reviews,  check out QUT Cite|Write

Leave a Comment


Your email address will not be published. Required fields are marked *