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SPE-01
2.2 Accelerated elution (Flash column chromatography)
The flow rate in manual column cleanup is limited by gravity and particle size of the sorbent. In
addition to unstable flow rate, the elution cannot be accelerated. In organic synthesis field, column
chromatographic purification has seen a drastic improvement after introduction of flash HPLC which
uses higher flow rate and sorbent of smaller particles. However this technique is seldom used for
sample cleanup in trace analysis due to the lack of suitable automated cleanup instruments.
The performance of the pump in SPE-01 is comparable to the pump used in a flash LC. It can deliver a
flow rate up to 20 mL/min. The high output pressure also allows to use smaller particles (10-20 um) to
improve the column efficiency. Below is an example of its application for pesticide residue cleanup in
tea.
Elution pattern of 5 pyrethroid insecticides on column packed with 3 gram florisil (fenpropathrin,
cyhalothrin, cypermethrin, denvalerate, deltamethrin).
As shown in the above figures, elution pattern at 18 mL/min is similar to that at 6 mL/min (near the
flow rate in manual column cleanup). A much faster elution speed can be achieved in automated
column cleanup.
Currently the particle size of packing material for SPE cartridges and column chromatographic cleanup
is normally of 40 um and above. Although it is known that a smaller particle gives better separation
efficiency and reduces elution volume in chromatography, it is not practical in manual operation as the
liquid will have problem flowing out. With the introduction of SPE-01, it becomes possible to use
columns with smaller particles.