17
Please always use a stable stand and a micromanipulator to move
the sensor into a semisolid sample like sediment, biofilm or soil.
The
minisensors
are standard sensors for robust long-term oxygen
measurements in gaseous or aquatic environments. Fixed
minisensors with a mechanically protected tip (
OXF500PT
; C) can
be used for insertion through a rubber septum without addition of
air to gas samples. Here the very sensor tip is flush with the tip of a
beveled needle and glued into it.
In case of fixed minisensors with a tip diameter of 1.1 mm
(
OXF1100
; C), the fixed sensor tip extends 1 mm from the needle
tip and is hence unprotected after removal of the protective cap.
Avoid any contact to harsh surfaces!
The needle-type oxygen sensors are also optionally available with
optical isolation
for measurements in samples with auto-
fluorescence. With this optical isolation, interferences between the
REDFLASH
indicator
luminescence and autofluorescence, e.g.
from photosynthetic pigments, are reduced. However, the optical
isolation causes an increase in the response time t90, which is the
time for 90% of the total sensor signal change (see respective
Sensor Specifications
).
5.2
Bare Fiber Sensors
The bare fiber sensors are identical
to the retractable needle-type
oxygen sensors, except that they do
not contain a housing. They
comprise only the bare optical fiber
with the
REDFLASH
indicator
immobilized on the sensor tip,
secured during transportation and storage in a protective plastic
tube (
PT
). The fiber-optical cable (
C
) is connected with the ST-plug
