Cleaning/Sterilizing (& declogging)

Mario Roederer roederer at
Tue Aug 28 13:56:24 EST 2001

We have recently become very fond of using 0.1N NaOH to "cleanse" our
cytometer.  The advantage is that it hydrolyzes DNA/RNA, which is one
of the major contributors to clogs for certain cell samples.  It
solubilizes cells quite well.

After any clog (partial or full), and at the end of the day, we
always run three things through the cytometer (make sure the fluid
from each runs long enough to go through the nozzle--i.e., boost for
15-30 seconds minimum).

(1) 0.1N NaOH (sterile filtered, made in the best water you have)
(2) CoulterCleanse solution
(3) dH2O (if end of day, we leave the tubing filled with distilled water)

After each of the tubes 1-3, we wipe down the outside of the sample
inlet tube with a kemwipe, while the instrument back-flushes sheath
fluid, and wash with dH20, to prevent contaminating future samples
with the base or the cleansing solution.

To sterilize, we may also run 70% ethanol through the system.

However, I strongly endorse the NaOH--It cleans clogs like nothing
else we've ever tried.


(Disclaimer:  I have no idea what 0.1N NaOH might do to your tubing,
nozzle, or other equipment.  We've used it for nearly a year with no
problems on multiple instruments, however, make sure you understand
the risks to your instrument of any solution you apply to your

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