How to Use Autosampler?

An Autosampler is an instrument which can be used for different laboratory applications, specifically for Gas Liquid Chromatography. It is, as the name implies, used to automatically introduce the sample into the inlets of the apparatus employed in the test. While it is possible to insert the samples manually into the instrument, it is no more a common practice as the auto samplers are more efficient and precise method to accomplish results.

Autosamplers can be classified by their capacity such as auto injectors that are capable of running multiple samples in one go. Robotic instruments also offer another classification of these autosamplers with the rotating robots that are being used widely. In the gas liquid chromatography process, the injector or the column inlet provide the introduction of the samples as a continuous flow of the carrier gases. Common inlet types include the split injectors, splitless injectors, on columns inlets, gas source inlet called as Gas switching valves and PTV injectors.  Other systems might include the Solid Phase micro extractions, Purge and Trap Systems and others. In split and splitless injector, the sample is introduced using the syringe to heated chamber.

With on column inlet, the sample is then introduced in its entirety sans the use of heat. The PTV injectors then introduce the sample at a very controlled temperature through a heater liner. In the gas source inlet method, the sample is injected into the gas stream right from the collection bottle, a methods that is used to introduce without any interruption to the flow of the gas.

The purge and trap autosampler system involves the bubbling of an inert gas through purging insoluble volatile compound and the aqueous samples using the matrix. These compounds are later on trapped in an absorbent column which on heating volatizes to the carrier stream.

The type of the autosampling system used largely depends on the application. In Gas Chromatography alone, there are 2 distinct types of columns being used based upon the type of autosampler being used. There are packaged columns that are usually made up of stainless steel and glass and contain highly granular, inert and solid material coated with some solid or liquid stationary phase.

The other type is Capillary Columns. These columns feature a small internal diameter that is being coated inside with the phase. Other types of capillary columns are made up of semi solid construction which allows greater flexibility. This allows a long column be tight wounded into coil which takes up very less room.

While it is usually gas liquid chromatography that often comes to the mind when are discussing autosampler types, there are samplers that are being used in different applications from the geological surveys to life sciences, Pharma industry to water quality testing and nearly every other application in the materials and life sciences as well as quality control testing of all types. These instruments have allowed the labs to handle minute and high samples while increasing efficiency and production.