FlowStar2 LB 514
3. Measuring Cells
37
3.5 Cleaning the Measuring Chamber
If the measuring cell has become clogged, for example by gel formation or
bending of the outlet line, the cell may get damaged by the pressure of the
HPLC pump, which may be up to 400 bar. As a consequence, eluate will
flow into the measuring chamber.
To prevent damage to the photomultiplier, a
leakage sensor
is installed at
the lowest point of the counting chamber, which detects and signals even
minor amounts of liquid, so that you can take action in due time and prevent
possible damage or, at least, kept it to a minimum. Moreover, at this point,
an outlet is installed as an
emergency outlet
, to which a hose is to be
connected which is led out on the front of the device, so that spilled liquid
can be drained to a waste container.
If you notice that liquid has spilled into the counting chamber, sepa-
rate the device from mains immediately!
Clean the chamber thor-
oughly. Special precautions have to be observed depending on how
much liquid has escaped! Wear protection glasses and gloves.
Liquids from admixture cells
often contain aggressive substances which
have to be removed completely; otherwise, they will continue to have a
harmful effect on the device and may ultimately damage it. For this reason,
the device should be cleaned by
B
ERTHOLD
T
ECHNOLOGIES
service person-
nel as this requires disassembling of the detectors.
In
Solid cells
the eluate includes radioactive substances which have to be
removed carefully, taking special precautions. Dry the chamber using a
soft cloth or filter tissue. Possible deposits from a radioactive substance
are irrelevant for the measurement, since the radiation cannot reach the
scintillator due to the limited range of the isotopes involved. Clean the win-
dow of the photomultiplier with a soft cloth.
It is recommended to leave the cleaned measuring chamber open over
night for drying, covered with a black cloth to avoid incoming light.
Always make sure that the photomultipliers are not exposed to light!
Clean them only in subdued light (light bulb).
Check the emergergency outlet after a leakage to make sure no liquid
is dried inside and may block the outlet. In case of a blocked emer-
gency outlet tubing please replace the tubing from outlet to waste
container.