Gas Chromatography
Chemito GC 1000, Chemito Instruments, India

Gas Chromatography (GC) is a commonly used separation technique. It can be used for qualitative and quantitative analysis of volatile compounds such as hydro carbons, fatty acids and organic solvents. It is also used for analysis of organic pollutants such as pesticides, herbicides in environmental studies. A broad variety of samples can be analyzed as long as the compounds are sufficiently thermal stable and volatile. For all the chromatographic techniques, there is a mobile phase and a stationary phase. The mobile phase in gas chromatography is an inert gas such as nitrogen or helium. The stationary phase is an inert solid support inside glass tubing called a column. The compound to be analysed is evaporated depending upon its boiling temperature. The gaseous compounds interact with the walls of the inert column and eluted at different time, known as the retention time of the compound. The retention time obtained for each eluted compound is compared with the standard for qualitative analysis of compounds. 

The key components of GC includes a source of gas as the mobile phase, an inlet to deliver sample to a column, the column where separations occur, an oven as a thermostat for the column, a detector to register the presence of a chemical in the column effluent, and a data system to record and display the chromatogram. Packed and capillary column are the two types of column used in GC. The capillary column has much lesser internal diameter and is efficiently used for analysis of minute concentrations of compounds. The Chemito GC 1000 gas chromatograph has a packed column configuration with FID and TCD detector systems. The instrument is controlled by a microprocessor and can be operated through a keyboard with 22 functional keys. The keyboard can provide easy functional control over all analytical parameters and can be operated in user friendly manner. There is also facility for storing a set of analytical parameters that saves valuable time for the user. The instrument is equipped with multilevel temperature programming and oven temperature ranges from 99°C to 450°C.The GC 1000 also comes equipped with built in control module which when used with system control software assist the user in total instrument control from a computer via a port.