Operating the bbe BenthoTorch
bbe BenthoTorch Manual Page 21
M
EASUREMENT BY BBE
BT
The samples are measured directly on site with the BT. Each plate is measured a few times (around
5) to “cover” the whole area. If the biofilm shows high patchiness, more measurements for a more
representative average value are performed. It is important to remember that the measurement area
of the BT is only 1cm², in a circle.
S
CRAPING AND TRANSPORT
It is better to scrape the samples directly “at site”. If such a possibility does not exist, the samples are
transported to the laboratory. For this, the samples are stored in a foil bag with a piece of a moist
sponge and filled with air to prevent damage to the biofilm. The closed bags are then stored safely in
an isolated box with ice packs to keep the samples cool.
At the laboratory, the flat plates are scraped with the blade of a cutter knife to remove the whole
biofilm from the substratum without damaging it. The sample is put into 25-50ml of water. The volume
of the water sample (V
p
) and the area scraped (A
scr
) should be noted for subsequent calculation.
Optionally, to create a homogenous sample, the solution is exposed to an ultrasonic bath for 5
minutes and stirred afterwards.
E
XTRACTION AND MEASUREMENT OF CHLOROPHYLL
-
A
(DIN
38
412-L16)
Materials und Methods:
- Chemicals:
o 90% ethanol
o HCl 3M
- Materials/Instruments:
o Glass fiber filters (Whatman GF/F)
o Vacuum filtration apparatus
o Vacuum pump
o Brown glass bottles (around 50ml for extraction)
o Pipette 10ml
o Spectrophotometer (LKB Biochrom 4050 Ultrospec II UV/Vis Spectrophotometer)
o Cuvette for a spectrophotometer (1cm)
o Syringe and syringe filter (0,45µm)
Extraction:
Using the vacuum filtration apparatus, the sample is filtrated over a GF/F filter with a vacuum of
around 400mbar. The filter is put into a brown glass bottle with 10ml (V
E
) of 90% ethanol making
sure the whole filter is covered with ethanol. The bottle is closed tight and incubated for 12 to 24h
in darkness at room temperature.
Spectrophotometric measurement:
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