Gas Chromatography

Gas Chromatography (GC) -

CLICK HERE👉Gas chromatography (quick animation)

The chromatographic technique where the mobile phase is a gas.

GC is currently one of the most popular methods for separating and analyzing compounds. This is due to its high resolution, low limits of detection, speed, accuracy and reproducibility.

GC can be applied to the separation of any compound that is either naturally volatile (i.e., readily goes into the gas phase) or can be converted to a volatile derivative. This makes GC useful in the separation of a number of small organic and inorganic compounds.

Equipment:

A simple GC system consists of:

1. Gas source (with pressure and flow regulators)

2. Injector or sample application system

3. Chromatographic column (with oven for temperature control)

4. Detector & computer or recorder

CLICK HERE👉Gas Chromatography Explained (In Hindi)

Carrier gas: He (common), N2, H2

Pinlet 10-50 psig

Flow = 25-150 mL/min packed column

Flow = 1-25 mL/min open tubular column

Column: 2-50 m coiled stainless steel/glass/Teflon

Oven: 0-400 °C ~ average boiling point of sample

Accurate to <1 °C

Detectors: FID, TCD, ECD, (MS)

Mobile Phase: GC separates solutes based on their different interactions with the mobile and stationary phases.

Carrier gas – Main purpose of the gas in GC is to move the solutes along the column, mobile phase is often referred to as carrier gas.

Common carrier gas: include He, Ar, H2, N2.

CLICK HERE👉GC Practical Experiment

Advantages Gas-solid chromatography (GSC):

- long column lifetimes

- ability to retain and separate some compounds not easily resolved by other GC methods, viz.

geometrical isomers, permanent gases etc.

Disadvantage:

- very strong retention of low volatility or polar solutes

- catalytic changes that can occur on GSC supports

- GSC supports have a range of chemical and physical environments, viz. different strength retention sites ‚ non-symmetrical peaks‚ variable retention times

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