A PLOT column, or Porous Layer Open Tubular column, is a capillary column used by gas chromatography, with the injected sample undergoing a stationary phase adsorption process. The stationary phase of the PLOT column is based on an adsorbent or porous polymer. The most common PLOT column stationary phases consist of various derivatives of styrene and alumina. These particles are bound to the surface of the capillary by means of a chemical bonding or by "glueing". Because the column particles are porous, they act as a kind of "molecular sieve", but there is no separation of particle size but separation polarity. The greater the polarity of the column and that of the analysis component, the greater the affinity between the stationary and the mobile phase. Characteristics
PLOT columns have very high affinity with almost all types of organic compounds and thus high retention. They can be used to achieve divisions that are impossible with conventional stationary phases. Another advantage is that in some columns, conventional columns must be used under ambient temperature. In the PLOT column, the same separation can easily be performed above this temperature.
The PLOT column has an internal diameter of 320 - 530 μm. The coating is 5 - 50 μm thick. In addition to the PLOT column there is another type of open tubular column. This is the WCOT column. However, the difference with this column is that the PLOT column has a fixed stationary phase and the WCOT column is a liquid. Use
PLOT columns are often used in the analysis of sulfur gases, noble gases, light hydrocarbons and volatile solutions. Benefits
PLOT columns have a number of advantages over a packed column. They have higher efficiency, faster separation (in seconds), the column is ready for reuse (less than 30 minutes) and less tools are needed.
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