More excitement on o-ring position and transport
In my last post, I concluded that switching the o-ring position from below the membrane to the top in the sepcon produced no leaks. The reason for this switch was to reduce the 1mm “dead-space” (created by the o-ring) that adds to the unstirred water layer (UWL). The next thing that Barrett and I looked into was shaking to reduce the UWL more. I focused on spinning in the Tecan as opposed to the tabletop VWR orbital shaker that Barrett used as seen here. The shaking settings in the Tecan were: duration = 540 sec, mode = orbital, and amplitude = 6 mm. This brings the shaking to ~30rpm. The results of the first trial are:
Notice the minimul difference due to o-ring position. The second trial’s results:
Here, it seems that transport was quicker with the o-ring on the bottom:I did not expect this. These results are similar to what Barrett saw as well. The third trial I added a PET transwell to the mix:
The transport through the PET transwell is drastically faster than both sepcons. Once again, the transport through the sepcon where the o-ring is on the bottom is slightly faster than where the o-ring is on the top.
O-ring placement makes very little difference in transport while shaking at max. speed (~30rpm) in the Tecan. To see where the the o-ring placement is best for transport, measurements will have to be taken at a higher rpm.