3/8/2023 0 Comments Dynamic light scattering wyattThere are some limitations to what the DLS unit can do. Compiling SoS’s under 500 or so gave a reasonable estimate of the population. Counts were lower (3e5) and had much larger variation in SoS’s. SoS’s are in the 500 range and while there is a small peak at a diameter of about 5nm, there is a larger peak around 50nmĪ 1:10 dilution of 2mg/ml BSA was also used. Sigma 5nm gold colloid suspension (G1402-25ML) diluted 1:10 also gives a strong signal (2.5e6 cnt/s) but has a bimodal population. Sigma 0.3 micron latex bead suspension (LB3-1ML) diluted 1:2000 gives a signal in the 3.0e6 counts/second range with a mean population diameter of about 500nM and a %polydispersity < 10. See page 2-14 of the Dynamics Users Guide If you notice longer stabilization time periods, please contact Mike. The NanoStar ramps at approximately 15 degrees per minute, so it should only take about 4 minutes to get from +4☌ to 60☌ (assuming an ambient temperature of ~25☌). In practice, it takes only a few minutes to reach and stabilize target temperatures. Open the main stem valve and set the line pressure to 20psi with the needle valve. If the set point is 20☌ or lower, the nitrogen purge gas must be used to carry away condensation from the Peltier cooling unit. Operating temperature is set in the Dynamics software by opening the Instrument panel in the Parameters node and entering a value for Set Temp (☌). Data can be collected between 4☌ and 100☌ with a claimed accuracy of 0.01☌. The NanoStar is equipped for temperature controlled measurements. Temperature control (or Why is there a N2 tank on the benchtop?): Since they don’t specify the rotor, a reasonable guess would be an RCF of 1000-1500 x g.Ģ. Wyatt’s recommendations for removal of dust are either filtration through a 0.2micron filter or spinning the sample for 10-15 minutes at 3000 rpm (sic). If you are working with material straight of a SEC column, it’s unlikely to be a concern, but otherwise you should be aware of the issue. Wyatt makes a point of noting that dust in solutions can be a problem with their instrument. For operating instructions, please contact Mike. It is a set of notes on various topics which may be of interest to users. This is not a detailed set of instructions for using the NanoStar.
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