Luminex xPONENT for MAGPIX 4.2 - Manual (Page 33)

when the analyzer flushes the sample lines after sample acquisition and expels
approximately 75 µL of sample back into the well.
Examples
• If you use a sample volume of 50 µL and aspirate 50 µL, you acquire air bubbles.
• If you use a sample volume of 200 µL and a standard sample pickup of 50 µL, the well
overflows when the analyzer washes the sample lines after acquisition and expels fluid
back into the well, because the amount of fluid expelled back into the well is approximately
75 µL.
CAUTION: Sample volume is critical to the proper functioning of your
MAGPIX instrument. Aspirating too few beads can result in
insufficient bead count or insignificant data results. Aspirating too
many beads can result in saturation of the chamber and prevent
proper bead classification, which may also result in low bead
counts or inconclusive data.
This formula quantifies the volume restrictions on the assay design:
Total well volume (µL) - Sample uptake volume (µL) + 75 (µL) <Maximum Well Volume (µL)
Where:
• Total well volume = Starting sample volume before the instrument acquires sample.
Sample volume is determined by the consistency of the bead set.
• Sample uptake volume = Uptake volume for acquisition (program this in the protocol as
sample volume).
• 75 (μL) = Volume expelled back into the well.
• Maximum well volume = The maximum volume capacity of the wells in a selected 96-well
microtiter plate.
You can change the sample size while running a batch using the Change Volume button on
the Current Run tab.
If you are running a MagPlex kit, follow the kit’s product insert or use the software protocol
provided.
Do not dilute MagPix Calibration or Verification beads, or the Fluidics 1 and Fluidics 2 beads.
Plates
Follow these guidelines when choosing plates:
• When using uncovered plates, use black opaque plates to reduce photobleaching.
• For heated assays, use CoStar ® Thermowell ® 96-well, thin-wall polycarbonate, model P
plates.
• For unheated assays, use a 96-well plate with an overall height no greater than 0.75
inches (19 mm).
CAUTION: The heater block or plate can be hot and can cause personal
injury when touched. Use care when you are working with it and
do not touch it.
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