Semiautomatic pipette

Membrane filters are used under vacuum, with positive pressure, or with gravity. Filters have been incorporated into certain disposable tips for use with semiautomatic pipettes. These filters minimize the exchange of aerosol droplets between the tips and the pipette. This is of particular importance for DNA amplification and microbiological procedures. Other membrane filters are designed for ultrafiltration and are available with a variety of pore sizes for selective filtration. Ultrafiltration is a technique for removing dissolved particles using an extremely fine filter. It is used to concentrate macromolecules, such as proteins, because smaller dissolved molecules pass through the filter. 

Syringe-barrel cartridges, disk-holders, plastic pipette-tips, well plates vacuum manifolds for semiautomatic batch processing fully automated autosamplers, xyz liquid handlers and robot-controlled work stations. 

In laboratories that have a large number of samples to analyze, some degree of automation has become essential. SPE is amenable to automation and is used widely for sample pretreatment. A popular system consists of an array of extraction plates with wells that hold 96 collection tubes, usually in rows of eight tubes each. An assembly of eight automatic pipettes applies samples to the system one row at a time. Semiautomatic elution is also employed. With this system the time needed to process 96 samples is reduced to < 1 h. 

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