An auto sampler is a tool which is used in various different laboratory applications, particularly gas-liquid chromatography, where it is used as its name suggests to automatically presenting a sample to the inlets of the device being employed in a specific test. Although it is possible to manually insert samples with many tools, this is no longer the frequent practice, since auto samplers provide a much more efficient and reproducible method.
Auto samplers may be classified by their capacity, like auto samplers instead of auto-injectors; the latter tool is capable of running more than 1 sample at once. Robotic instruments provide another classification of auto sampler, with rotating/SCARA robots being one of the most frequently used. In gas-liquid chromatography, the column or injector provides for the introduction of samples into a constant stream of carrier gas. Common inlet kinds are the split/split less injectors, on-column inlets, PTV injectors, the gasoline supply inlet also referred to as a gas switching valve, purge and trap systems and SPME solid phase micro extraction systems. From the split/split less injector, the sample is introduced into a heated room by means of a syringe.
With an on-column inlet, the Sample is introduced in its entirety without using heat. PTV injectors present the sample via a heated liner at a controlled pace. In the gas supply inlet method, the sample is put into the gas flow from collection bottles, a method that allows samples to be introduced without disrupting the carrier gas flow. Purge and trap auto sampler systems involve bubbling an inert gas through aqueous samples, purging insoluble volatile compounds from the matrix. These volatile compounds are subsequently trapped in an absorbent column that is then warmed – the volatiles are led into the carrier stream. Solid phase micro extraction Sprees a cheaper alternative to purge and trap systems that provides increased ease of use and a lower price.
The Sort of automatic sampling System used depends largely on the particular program; in gas chromatogram alone, there are two unique kinds of columns used – together with the various kinds of auto sampler being more suitable for one or the other. There are packed columns usually made from glass or stainless steel and containing an inert, strong and extremely granular material that is coated with a liquid or solid stationary phase. The other kind is capillary Columns; those columns feature a very small internal diameter, with the interior of the column being coated with the stage. Other capillary columns are created out of a semi-solid structure and parallel microspores; this design allows for great flexibility, so a very long column can be wrapped into a tight coil that takes up far less space.