When designing its Extrahera automation system, one of the important goals of the Swedish Biotage company was to obtain an instrument capable of automatic sample enrichment and cleaning within a few easily programmable steps, that is at the disposal of analysts during the sample preparation for processing solid-phase extraction (SPE), supported liquid extraction (SLE), protein and phospholipid removal (PLD) and protein precipitation (PPT).
Depending on the configuration of Extrahera, the samples can be placed on the sample holder either in 96-place plates or in test tubes placed in a test tube holder. For extraction, SPE/SLE/PLD/PPT plates of standard size, as well as 1, 3 or 6 ml columns can be used. If the samples to be processed are in test tubes, 24 tubes can be placed in Extrahera at the same time, while in the case of plates, maximum the 96-place plates can be used. For test tubes 4-channel pipetting heads, for 96-place plates 8-channel pipetting heads can be used. The pipetting heads can be replaced in a few minutes.
The dual format design of Extrahera ensures the processing of the samples without cross-contamination. On the upper level the sample holder, the extraction vessel support, the 25-ml containers of the 5 solvents, and two pipette tip holders – one for the sample and one for the solvents – as well as a pipette tip bin are placed. On the lower level there is a four-position carousel in which the waste outlet plate and three fraction collectors can be placed. The carousel rotates the waste outlet plate and the fraction collectors into the internal position according to the method, then a lifter positions them to the extraction vessel.
The samples and the solvents are moved with the help of the pipetting head and the 1 ml disposable pipette tips. In the case of moving identical solvents a set of pipette tips can be reused, however, the pipette tips used for handling the samples can be used only once. 5 different solvents are used for the dilution of the sample, for column conditioning, washing the sample, and dissolving the fractions. These solvents are drawn by the pipette head from the 25 ml internal solvent reservoirs. The filling of the solvent reservoirs is done by the ultrasonic level detection at the start of the method, the amount of the removed solvent is replaced by the solvent pumps automatically from the outer solvent vessels. The sample preparation steps (column conditioning, sample loading, sample washing, elution of fractions, column drying) are carried out with positive pressure which needs clean nitrogen gas or compressed air. The gas pressure can be adjusted for every step of the method from the software, thus the flow rate on the cartridge can be varied.
The control and programming of Extrahera is done with the Linux-based internal software developed for SPE, SLE, PLD and PPT tasks via a 12″ color touch screen. The internal software contains pre-prepared methods which can be either converted or completely new ones can be made in accordance with the users’ needs. The results are stored in pdf file format, which can be exported to the USB pendrive.
- pipette head: 4 or 8 channels
- pipetting speed: adjustable from the software
- pipetting accuracy:
- 50-100 µL:±2,0%
- 500 µL: ±1,5%
- 1000 µL: ±1,0%
- pipetting reproducibility: 1%.
- solvents: 5 solvents in inner 25 ml reservoirs, automatically refilled
- applicable pressure: 0-5 bar
- needed gas for extraction: 6-10 bar pressure, at least 1 liter/min flow rate clear nitrogen or pressurized air
- needed gas for moving of the pipette head and for sealing: 5 liter/min flow rate, 6 ± 0,2 bar pressurized air or nitrogen
- pipette tip volume: 1 ml
- waste outlet: vacuum pump is needed
- dimensions: 860 x 570 x 730 mm, 75 kg.