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Recommended Equipment

Performance specifications for each Q-Plex™ array are met before it leaves the Quansys facility. However, along with the actual components of the kit and the process of following the protocol, the equipment, and consumables used during the testing can affect the performance of the assay. At Quansys, we use the following equipment and supplies and recommend our customers do the same to ensure you have optimal results. If you have any questions about the equipment you plan to use with the Q-Plex array, please contact Quansys technical support before running the assay.

Plate Washer

Why is it important?

Washing is an integral part of running a Q-Plex kit. All of the reagent and sample must be removed from the wells at each assay step. Improper washing such as scratching the bottom of a well, allowing the wells to dry, or not removing material from a previous step can have adverse effects on the assay performance as seen below.

Quansys recommendation:

Quansys has used the BioTek ELX 405 for years and have found it reliable for optimal performance.

Click here to see the procedure we use with this washer.

When programming any automatic plate washer:

  1. Dispense 400 µL of wash buffer into each well to completely fill the well, repeat at least 3 times at each step.
  2. Ensure the tips do not impact the bottom of the well during aspiration.
  3. Use a slow dispense rate to avoid removing bound material from the bottom of the well.
  4. After washing, if there is a significant amount of residual wash in the wells or the amount of residual wash is not consistent across the plate, tap the plate upside down on a paper towel to remove residual wash.
  5. If using an 8 channel washer to wash an entire plate, program the washer so that each column of wells is not left dry while other wells are being washed.

If automated plate washers are not available, hand washing is acceptable. Fill each well with 400ul of wash buffer and shake out. Repeat 3X or 6X depending on which wash step. At the end of each wash step, tap the plate upside down on a paper towel. Proceed immediately to dispense the next solution so drying does not occur.

Plate Shaker

Why is it important?

Q-Plex kits require constant and aggressive shaking. Insufficient shaking can cause a decrease in sensitivity while over-shaking can cause samples to splash onto the lids or cover of the plate.

Quansys recommendation:

At Quansys we use Barnstead/Labline 4625 plate shaker with a 500 rpm shaking speed.  This item is no longer available for sale, but its recommended replacement, the Thermo Scientific 88880023 Microplate Shaker, is a great option.

Sample Preparation

Why is it important?

Samples and calibrators must be diluted before being loaded into the Q-Plex plate. Many consumables allow proteins in the sample to bind to their surface, which can affect assay performance. Using a low binding 96-well plate to assemble your calibrators and samples will ensure your wells are loaded onto the Q-Plex plate with minimal time variance and will reduce any potential assay drift.

Quansys recommendation:

Low-binding polypropylene plastics are preferred for sample dilution over polystyrene plastics or glass. At Quansys we use polypropylene (low-binding) V-bottom, 96-well plates to prepare sample and calibrator dilution.



Why is it important?

Any variation of performance of pipette and/or user error diminishes the precision of the assay.

Quansys recommendation:

We recommend verifying the accuracy of each pipette internally weekly and with the manufacturer annually. In addition, you can brush up on your pipetting technique by reviewing our Tech Tip on pipetting here.

Lab Temperature

Why is it important?

The ambient temperature of the lab where the Q-Plex array is tested can change the sensitivity of the assay.

Quansys recommendation:

Labs at Quansys are held at 21-22⁰C (70-72⁰F). An assay tested at 18⁰C (65⁰F) may have diminished signal and sensitivity compared to the results at Quansys. This decrease in signal will not affect calculated concentrations of samples or precision of the assay but a decrease in sensitivity may be observed.

Deionized Water

All reconstitution or dilution requiring water should use deionized water.