Understanding the Significance of GC Capillary Column

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

Understanding the types of GC capillary columns used in making zero-air gas generators in detail:1. 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.

2. 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

• 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.

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.

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