Maintenance
Chapter 5
Zetasizer APS Basic Guide
Page 5-5
In general, a size measurement of a sample requires less cleaning afterwards than a
thermal trend measurement of the same sample (as the thermal trend denatures the
protein which exposes hydrophobic parts which can give it a tendency to stick to
the cell and tubing). The user providing the samples should be in the best position
to know what could be an efficient cleaner for their sample, however the following
protocols have been shown to be effective for a variety of proteins.
The rinse fluid scattering (a parameter selected in the schedule settings) should be
monitored to make sure there is no build up of contamination in the optical cell.
For most protein samples tested (albumins, lysozyme, antibodies), the washing
protocols outlined below have worked well for concentrations up to 200mg/ml:
For standard size measurements:
Select Custom Wash
Activate all three steps by clicking on them
Choose 600
µ
l of rinse fluid/solvent, then 1250
µ
l of wash fluid, and finally
5000
µ
l of rinse fluid
Deionised water is suggested as the rinse fluid and 0.1M NaOH as the
wash fluid
For thermal trend measurements:
Use either use vigorous wash or select custom wash for concentrations of
proteins <10mg/ml
Activate all three steps by clicking on them
Choose 1250
µ
l of rinse fluid/solvent, then 3750
µ
l of wash fluid, and finally
7500
µ
l of rinse fluid
Deionised water is suggested as the rinse fluid and 0.1M NaOH as the
wash fluid. Higher concentrations up to 1M might be needed to keep the
system clean.
After a longer period of non-use or as a procedure to use if the system will
not be used for a long period:
Rinse the system with 10ml of deionised water through each inlet.
If the instrument is to be left unused for a very long period, rinse through
the system extensively with water and then with 20% ethanol in water to
prevent anything growing in the system.
Extensive cleaning
If the rinse fluid scattering has increased to
greater
than 50-60kcps, it is recom-
mended that a thorough wash with 1M NaOH and 1M HCl is performed using
the Wash control tools.
MAN0494-1 (Zetasizer APS Basic Guide).book Page 5 Friday, August 9, 2013 2:08 PM
