With VVP’s sensor controlled pipetting a real time analysis of the flow rate of the liquids entering and leaving the tip is possible. Now, full pipetting diagnostics have been implemented in the software as easy click on/off commands giving the system the ability to not only half pipetting of a single channel while the rest continue to pipet correctly but now it is possible to correct a single error in the 96 VVP, 24 VVP (Large Volume) and Fixed-8 VVP pipetting tools. Once a head has completed an aspirate command, if a single or multiple channels had pipetting errors, the head rises out of the liquid, spears just the channels that had errors, and will dip the head again in the plate while only aspirating the now empty tips. The system also analyzes the well definition and offsets itself to run the aspirate in a slightly different position within the well.
Cot & Clog Detection & Correction
Clot & Clog detection can be optimized by setting threshold parameters depending on your samples matrix. Once anything starts to interfere with the tip opening and there is an interruption of the average flow rate, that independent channel closes before the clog/ clot is pulled into the tip permanently clogging it. The rest of the tip finish aspirating correctly and the head rises out of the samples, clear the just the tip that and an error and the head re-dips into the samples and re-tries to aspirate the sample in a different place in the well.
Short Sample Diagnostics
Short sample or Air-In-Sample diagnostics analyze the flow rate of the liquid into the tip and when is ‘senses’ air either at the end of and aspiration or during the aspiration and error is create. A user may program a re-try, have it put back the sample in the source well or transfer the volume and report the actual volume transferred.
Tracking Error Diagnostics
Usually during method development well parameters are set that are used by the arms to track down as the sample is aspirated and track up as samples are dispensed. If the sample is aspirated faster than the arm tracks down an error is created where the system ‘sees’ air in the sample column.