I’m running a standard calibration of my i7 Span-8, trying to improve the precision of the 8 channels on my system. Running the low volume range (0-19.9) I’m finding that the variance of the 1uL volume is significantly different than the other targets I’m using.
This makes sense, very low volumes are hard to hit, and require finesse - and really should not be grouped into the other volume targets as it may throw off the applied calibrations over the whole range. A good visual is in this chart where the normalized residuals are all fairly similar except the 1uL group, which can negatively affect the regression model for the whole range. The term is heteroskedasticity if you want to read more into it.
My thought is this - the i7 only has three volume groups - Small, Standard, and Large - but I’m curious if I could add a new group to the mix and if the software would actually recognize this group when making decisions on which calibration to apply.
I can add the dictionary in easily, but I’m weary to do this my real system for fear of bricking the instrument (bad) but I’m not sure if I can test this in simulation, or how to determine if the scaling is being applied to the pump movements.
Any ideas or recommendations? I would love to have a specialized calibration model for these “very low” volumes, but not sure if this crazy idea would work of if I’m better off working out these problems on a case-by-case basis.
I wouldn’t now how to do it that way, but I wonder if you can figure out a way to build multiple techniques for each volume range, and set a rank for each of those in such a way that in your transfer/aspirate/dispense command, that it will autocorrect the correct technique (with customized calibration).
If you aren’t using auto-select at all, then you could set all of other techniques to “do not auto-select”, and only do that for the for the techniques where you need 1 ul transfers. If you had multiple different types of liquid that each required their own specific calibration offset/scaling factor, then you might have to set up different liquid types to make the auto-select work properly in that case.
This doesn’t help if you are trying to do this globally. Hope this helps you, at least in a way that wont potentially brick anything!
You can utilize a technique on the browser that supports multiple techniques based on the volume you wish to aspirate. This range can then be calibrated using a scaling factor. Additionally, you can set the technology to auto-select. The process operates based on the volume you’re working with, selecting the appropriate technique that has been calibrated.
*or example:
The first technique is suitable for volumes between 0.01 and 3, with a scaling factor of 0.93.
The second technique is suitable for volumes between 3.01 and 5.0, with a scaling factor of 0.95.
The third technique is applicable for volumes between 5.01 and 50, with a scaling factor of 1.034.
When working with a liquid type named ‘RNA’, during the transfer process, select ‘RNA’ as the liquid type and click on ‘Auto-Select’. Based on the volume, the software will then choose the technique that best matches the volume.
