Chemistry - Chromatography
Chromatography can be used in both qualitative and quantitative analysis.
Sometimes referred to as separation science, it is used to separate the
components of a mixture by selective removal from a moving fluid (gas or
liquid). In all forms of chromatography there are two distinct phases: a
stationary phase and a mobile phase.
The different components of a mixture will be attracted to the stationary
and mobile phases to different extents. Chromatography uses these
differences in attraction to separate the components.
The moving fluid, referred to as the mobile phase, passes over a
stationary phase. The components of the mixture are separated according to
their relative attractions to the mobile and stationary phases.
The four main types of chromatography are paper chromatography, thin-layer
chromatography, gas chromatography (GC) and high performance liquid
The different bonding characteristics of each component with the mobile
and stationary phases are used to provide either an _R_f value (paper and
thin-layer chromatography) or a retention time (GC and HPLC) which enables
ready identification of each component.
The chromatograms produced with GC and HPLC, reflect the qualitative and
quantitative aspects of chromatography.
Chromatography has many applications in chemistry and associated
industries. These applications generally involve separating, identifying
and quantifying the components of a chemical mixture:
* testing for performance-enhancing drugs
* detecting impurities in foodstuffs and pharmaceuticals
* identifying and measuring environmental pollutants
Previous | Next