Waters Ostro Sample Preparation Products - Manual (Page 2)

[ Care and Use ManUal ]
2 Ostro Enhanced Protein Precipitation Plate
Step 4: mixing
aspiration (Preferred)
Aspirate the samples up and down 3X by a manual pipette, or an
automated sample handler may be used to ensure complete mixing.
Aspiration is the preferred mixing mode which will provide complete
mixing and a clear filtrate. Alternatively, an automated sample han-
dler may be used.
Vortexing
If vortexing is chosen for mixing, it is critically important to vortex
vigorously and thoroughly to observe the best product performance.
Apply a cap mat and securely seal (e.g. use a cap roller). This will
prevent leakage and cross talk during mixing. Shake (mix) the loaded
Ostro plate/collection plate assembly on a vortexer.
Note: There is no need to remove the cap mat from the Ostro plate
before applying vacuum. If positive pressure is to be used, remove the
cap mat, carefully.
Note: Excessive mixing at too high a setting (e.g., setting 8 on a
1-10 scale) could cause cross talk. Under-mixing (e.g., setting 2 on
a 1-10 scale) may cause clogging or a cloudy filtrate.
Step 5: Sample filtration
Positive Pressure (Preferred)
After mixing, place the Ostro plate/collection plate on a positive
pressure processor and set the flow for 60 psi for 5 minutes. A higher
pressure can be applied if flow does not occur.
Note: The Ostro plate’s proprietary design prevents liquid flow
through the device until force has been applied.
Vacuum
After mixing, place the Ostro plate/collection plate assembly on a
vacuum manifold (e.g. Waters Vacuum Manifold P/N 186001831),
and apply 15” Hg of vacuum for 5-10 minutes. A higher vacuum set-
ting can be use if flow does not occur at 15” Hg.
Step 6: analysis
Discard the Ostro plate and remove the collection plate containing
clear filtrate from the vacuum device or positive pressure manifold.
Seal the collection plate and transfer it to the LC/MS/MS autosampler
or store for later analysis. Extracts may be directly injected, diluted
prior to injection, or evaporated and reconstituted with an appropriate
solvent.