Previously, I had data showing that 5nm gold in 10mM salts went diffused through pnc-Si membranes. I was able to achieve this twice, although the second time took two days before the gold signal was intense enough to observe via absorption. Here’s what has happened recently: 5nm gold will not pass through untreated SC 168,…
Here are the results of diffusion based protein separations at different salt concentrations and 50kD Microcons: We see a sharp cutoff between 31 and 45kD. Separations look like they have progressed further in 10mM salts rather than 100 mM (this is the opposite of what we see in pnc-Si). The 100kD data may also support…
The retrial on cellulose (100kD) gold separations gave similar results to the first study (results from Tecan scans): particle salt results 5 0mM no au in filtrate, retentate concentration 15 0mM no au in filtrate 5 10mM no au in filtrate, retentate concentration 15 10mM no au in filtrate I took the membranes and rinsed…
This is just a little update on the results of the pnc-Si, cellulose, and pes separations. When I added up the retentate and filtrate, it didn’t always equal the intensity of the starting sample (keeping in mind that I was unable to collect filtrate from PES and should re-try that separation). I took the percent…
Can viscosity be determined by dynamic light scattering? Dynamic light scattering in essence measures the diffusion of particles and calculates the hydrodynamic radius using the Stokes-Einstein relation, D = kT/(6πηr). To find a size using dynamic light scattering, you need to input the viscosity so it can perform the calculation. If we don’t give the…
We got a bunch of extremely nice EO wafers through the pipeline, and I’ve been trying to do some experiments with them. There’s very few pinholes on these wafers, and the pores are beautiful. My experiments so far have been w/ SC 166. Pore image: Contributed area distribution: We need the following figures for our…
I set up separations with 100kD cutoff Microcon (cellulose) membranes and protein standards. Here are the results: Due to shorter than normal gel, the myosin didn’t get resolved. However we can see a separation that appears to be fairly sharp. We have seen this in the past with cellulose. The different salt concentrations don’t appear…
Here are the sizes of the particle ladder by TEM. I compare to the previous unmodified DLS results in this table. Manufacturer’s Size TEM size Stdev DLS Size 5 6.6 .6 8 10 7.8 .9 9.4 15 12.7 .9 13.2 20 16.0 1.5 17.2 30 25.7 2.1 28.8 40 34.3 2.3 30.7 The particles aren’t…
This was the first try at using PES for protein separations by diffusion. 100kD cutoff Nanoseps were used to separate 10mM KCl and 100mM KCl standards. In both cases, the backside fluid was gone after 24hours. I don’t think evaporation was the problem; either the membrane sucked up the fluid or it was drawn up…
I reran the samples from this post on coomassie stained gels. The sensitivity is lower, but the results look reasonable. First off I check out how well the sum of the retentate and filtrate matched the starting sample. This was much closer with the 100mM trial. There seems to be more error/loss in the 10mM…