Understanding the Significance of GC Capillary Column

1
Understanding the Significance of GC Capillary
Column

• Capillary is a long narrow tube used in gas
  chromatography specifically in zero-air gas
  generators.  These are filled with the stationary
  phase and play a key role in the process of GC.
  It helps to pass differently through it at
  different temperature depending upon the boiling
  point of two compounds which need to be
  identified.
• The Capillary Column is of two different types
• Packed Column,
• Open tubular column

2

• Understanding the types of GC capillary columns
  used in making zero-air gas generators in
  detail-
• Packed Column,
• Packed GC Capillary columns are usually made up
  of stainless steel, nickel, glass, or Teflon. The
  amount of pressure drop per length is very less
  in a packed column. Its inner diameter may vary
  from 1.5m to 4mm and a maximum length of 3
  meters. They are having inert solid support or
  absorbent in their coating which works as a
  support material to the column. Absorbent like
  Porous polymers and finely graded silica gel is
  used in Gas-Solid Chromatography. In Gas-liquid
  chromatography, the stationary medium is
  supported with diatomaceous earth, if the
  corrosive solute is analyzed then sieved Teflon
  steel is used.

3

• Open tubular column
• Fused silica or stainless with high tensile value
  is used for its construction. The length and
  diameter may vary from 5-100mm and 0.1- 0.75mm
  respectively. In this, the stationary medium is
  not coated but is on the internal part of the
  column so that the gas flow faces the least
  resistance. To protect it from outer scratches
  polyamide coating is used.
• Understanding them more through-
• Wall coated open tubular column, (WCOT)
• The inner surface of the capillary column has a
  thin layer filled with liquid as a stationary
  medium whose thickness may vary from 0.05 to 3µm

4

• Support coated open tubular column, (SCOT)
• In this column, the inner part of the column has
  deposited a porous substance working as an
  adsorbent in the internal part of the column. The
  liquid absorbent work as support material to the
  porous substance.
• Porous layer open tubular column, (PCOT)
• A porous layer solid absorbent such as alumina,
  molecule sieve, or porapak is at the internal
  part of the column. These are well suited for
  light, gas, and volatile substances.
• Fused silica open tubular column, (FCOT)
• This column is internally covered by fused silica
  and is having a chemically bond stationary phase.

5
Understanding the Significance of GC Capillary
Columns for Zero Air Gas Generator Zero gas is
the air that has no or very less amount of
hydrocarbon. The oxidative catalyst like platinum
or palladium is used to convert air into zero
gas. It only contains less than 0.1 ppm of total
Hydrocarbon. The generator used a cellulose inlet
filter to remove all excess oil, particles, and
filters. There are many companies that deal in
the manufacturing of GC Capillary Columns,
wherein Quadrex has been the number one
manufacturer of GC Capillary Columns.
SOURCE
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ding-the-significance-of-gc-capillary-column.html