©
Spectradyne LLC, All rights reserved
21
Version 2.5.0 Revision 3, July 2020
Buffer Maintenance
Refrigerate the running buffer and bottles
➢
The running buffer and bottles should be refrigerated during long periods of inactivity
(e.g., overnight) to minimize algae growth.
➢
Running buffer should be replaced with fresh filtered buffer approximately
every
two
weeks.
Guidelines for Sample Preparation
Some optimization of sample preparation may be required when analyzing a sample for the first
time. Once the best sample prep for the analyte in question is determined, that procedure can
be used for future analyses of that analyte and its variations. The parameters below are suggested
targets for first-run samples.
For further details on method development,
please contact Spectradyne’s support team
at
Optimal sample parameters:
Concentration:
10
9
particles/ml below 300 nm, 10
8
particles/mL above 300
nm
Calibration beads
(optional):
Add calibration beads to final concentration ~10
9
/ml below
300 nm, ~10
8
/ml above 300 nm. Recommended size ~30%
below the cartridge max size.
Ionic strength:
~ 1 S/m (e.g., ~100 mM NaCl)
Surfactant:
1% polysorbate 20 or equivalent
Notes:
➢
Sample diluent and calibration particles:
❖
If ionic strength or surfactant in the diluent is a concern, then lower values can
be used.
❖
For first-run analyses, Spectradyne highly recommends mixing calibration
particles of a known size (typically NIST-traceable polystyrene beads) with the
analyte.
❖
Keep in mind that the sample diluent may be a source of nanoparticles!
➢
Running buffer:
❖
Important:
Running buffer does not contact the analyte sample until after its
particle distribution has been analyzed. The user should not be concerned that
ionic strength or surfactant content of the running buffer will affect the
measurements.
