Quantitative analysis (chemistry)


Quantitative analysis (chemistry)

In chemistry, quantitative analysis is the determination of the absolute or relative abundance (often expressed as a concentration) of one, several or all particular substance(s) present in a sample.

Once the presence of certain substance(s) in a sample is known, the study of their absolute or relative abundance can help in determining specific properties.

For example, quantitative analysis performed by mass spectrometry on biological samples can determine, by the relative abundance ratio of specific proteins, indications of certain diseases, like cancer.

Quantitative vs. Qualitative

The term "quantitative analysis" is often used in comparison (or contrast) with "qualitative analysis", which seeks information about the identity or form of substance present. For instance, a chemist might be given an unknown solid sample. He or she will use "qualitative" techniques (perhaps NMR or IR spectroscopy) to identify the compounds present, and then quantitative techniques to determine the amount of each compound in the sample. Careful procedures for recognizing the presence of different metal ions have been developed, although they have largely been replaced by modern instruments; these are collectively known as qualitative inorganic analysis. Similar tests for identifying organic compounds (by testing for different functional groups) are also known.

Many techniques can be used for either qualitative or quantitative measurements. For instance, suppose an indicator solution changes color in the presence of a metal ion. It could be used as a qualitative test: does the indicator solution change color when a drop of sample is added? It could also be used as a quantitative test, by studying the colour of the indicator solution with different concentrations of the metal ion. (This would probably be done using ultraviolet-visible spectroscopy.)


Wikimedia Foundation. 2010.

Look at other dictionaries:

  • Quantitative analysis — may refer to:* Quantitative analyst, in finance, someone who applies mathematics, among others stochastic calculus, to finance * Quantitative analysis (chemistry), in analytical chemistry, the measurements of quantities of substances produced in… …   Wikipedia

  • quantitative analysis — n. the branch of chemistry dealing with the accurate measurement of the amounts or percentages of the various components of a compound or mixture …   English World dictionary

  • quantitative analysis — noun Chemistry measurement of the quantities of particular constituents present in a substance …   English new terms dictionary

  • analysis — /euh nal euh sis/, n., pl. analyses / seez /. 1. the separating of any material or abstract entity into its constituent elements (opposed to synthesis). 2. this process as a method of studying the nature of something or of determining its… …   Universalium

  • chemistry — /kem euh stree/, n., pl. chemistries. 1. the science that deals with the composition and properties of substances and various elementary forms of matter. Cf. element (def. 2). 2. chemical properties, reactions, phenomena, etc.: the chemistry of… …   Universalium

  • analysis — n. examination of component parts 1) to make an analysis 2) a careful, painstaking, thorough; in depth; penetrating analysis 3) (ling.) discourse analysis 4) (chemistry) qualitative; quantitative analysis 5) (math.) vector analysis 6) upon… …   Combinatory dictionary

  • quantitative chemical analysis — ▪ chemistry       branch of chemistry that deals with the determination of the amount or percentage of one or more constituents of a sample. A variety of methods is employed for quantitative analyses, which for convenience may be broadly… …   Universalium

  • Quantitative structure-activity relationship — (QSAR) is the process by which chemical structure is quantitatively correlated with a well defined process, such as biological activity or chemical reactivity.For example, biological activity can be expressed quantitatively as in the… …   Wikipedia

  • surface analysis — ▪ chemistry Introduction       in analytical chemistry (chemistry), the study of that part of a solid that is in contact with a gas or a vacuum. When two phases of matter are in contact, they form an interface. The term surface is usually… …   Universalium

  • qualitative chemical analysis — ▪ chemistry       branch of chemistry that deals with the identification of elements or grouping of elements present in a sample. The techniques employed in qualitative analysis vary in complexity, depending on the nature of the sample. In some… …   Universalium


Share the article and excerpts

Direct link
Do a right-click on the link above
and select “Copy Link”

We are using cookies for the best presentation of our site. Continuing to use this site, you agree with this.