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Magnetic Tumble Stirring using the Reciprocating Tumble
Stirrer (VP 709) has been demonstrated to facilitate
resoluabilization of extracts dried in deep well microplates.
To test the ability of the Alligator Tumble Stirrer to
resoluabilize extracts in deep well plates we added 1.75 ml of MeOH: EtOAc: Me-t-Bu ether 60:30:10 to each of the wells of a
deep well microplate containing dried extracts from a large
library. The extracts were photographed via a mirror showing the
bottom of the plate prior to adding the solvents (photo #1). Next
we dispensed stir discs into all the wells except E1, F1, G1, H1
and all of column 2. (Column 1 was all the same extract so it
serves as a control for stirring and not stirring. Column 2 with
no stir disc serves as a partial unstirred control for the rest
of the extracts.)
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Photo #1- Dried Extract In Bottom Of Wells
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Next we stirred the
microplate at 65 tumbles per minute (high speed) and photographed
the bottom of plate after 25 minutes (photo #2). At this point all the stirred wells except C12
appeared to be totally dissolved while most of the unstirred
wells still had some if not all the extracts in the bottom the
well.
At this point we removed the stir discs with the
VP 408AM Magnetic Replicator and loading,
unloading magnetic block system
(VP 770)
and photographed the plate bottom (photo #3).
Next we aspirated the solvent from the plate and
again photographed the empty plate bottom (photo #4).
The visual evidence indicated that the extracts in the stirred
wells were dissolved in a few minutes. Although not all the
extract in the stirred well C12 was dissolved, a significant
portion was by 25 minutes. Furthermore, a target (bull's eye)
like pattern was present in the bottom tip of the well with the
clear areas indicating that the places where the disc had scraped
the extract off the well and the colored areas indicating a
depression in the wells where the disc could not physically
contact the well.
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Photo #2 - After 25
Minutes Of Stirring
Photo #3 - After Stir Discs
Were Removed |
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Column 2, which was not stirred,demonstrated 6 of 8 wells with
significant dried exact still in the bottom of the well. The 4
wells not stirred in column 1 also demonstrated significant
extract in the bottom of the wells while the 4 stirred wells of
the same extract were resoluabilized.
Note that this study was done before the advent of The
Rotary Tumble Stirrers ( VP 710 series). The VP 710 series
stirrers are capable of tumbling the stirs at much faster speeds
in the same direction (500 RPM). We recommend the VP 710 series
for stirring in deep well microplates because of the superior
movement of liquids in tall columns.
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Photo #4 - Extract Still In Bottom Of Wells After The
Solvent Was Removed
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