Gas Chromatography - Flame Ionization Detector Animation

Learn that gas chromatography uses a carrier gas (mobile phase) and a heated column (stationary phase) to separate vaporizable compounds. The system includes an autosampler or manual inlet to introduce samples into the continuous carrier gas flow.

A sample is injected via syringe through a septum into a heated chamber, where volatilization occurs. The carrier gas then transports the vaporized sample either in split mode (partial venting) or splitless mode (complete transfer) into the column.

Choose between packed columns with stationary phase coated directly on the column or capillary columns with stationary phase coated on the inner wall. Both types separate components based on differential partitioning and affinity to the stationary phase.

Control factors affecting component separation such as column temperature, carrier gas flow rate, column length, and sample amount. Components with less affinity to the stationary phase elute first, while those with greater affinity elute later.

Eluating compounds enter the flame ionization detector where they combust in a hydrogen-air flame, generating mainly carbon ions. Two electrodes—a positive nozzle electrode and negative electrode above the flame—create a potential difference to detect these ions.

The current produced between the electrodes is proportional to the amount of organic compound present. This current is measured with a voltmeter, amplified, and fed into an integrator for computer processing.

The number of peaks indicates the number of components in the mixture. The x-axis shows the time for analytes to reach the detector (retention time), while the y-axis represents the peak area, reflecting the amount of specific analyte present.