Analyses - Sartorius CombiSart Bedienungsanleitung

3.3 Line up your sterile culture media,
such as Nutrient Pads in petri dishes
or agar in petri dishes. Moisten
the nutrient pads with 3.0-3.5 ml of
sterile distilled or demineralized
water. The Dosing Syringe (16685-2)
with a sterile Minisart (17597-K)
attached, simplifies the addition of
water to Nutrient Pads.
3.4 Place a Bunsen burner with a
glass beaker containing a little
alcohol and a pair of blunt-tipped
forceps next to the autoclaved filter
holder.
If you are working with a stainless
steel filter holder and will sterilize it by
flaming, proceed as follows:
a) Locale the sterile packaged
membrane filter within easy reach.
b) Turn on the vacuum source and
remove the stainless steel funnel.
c) With the Bunsen flamer flame the
filter support including the stainless
steel frit by opening the valve (turn
to 6 o'clock) to draw the flame
through the filter support. Then
close the valve (turn to 9 o'clock).
d) Hold the stainless steel funnel in
one hand and flame it from below.
e) Reposition the stainless steel funnel
on the base, and lightly push down
on the quick-lock clamp to secure
the funnel (there is no need to force
the clamp down to it's full extent).
Using a spiral pattern flame the
funnel on the inside from the
bottom to the top.
f) Flame the lid on the inside, and
place it back on the stainless steel
funnel.
g) To accelerate cooling of the filter
holder and simplify insertion of the
membrane filter, rinse the filter
holder with sterile water (e.g. using
a Dosing Syringe with a sterile
Minisart attached). To remove the
water via vacuum, open the valve
(turn to 6 o'clock), then close it
(turn to 9 o'clock).
14
h) Sterilize the blunt-tipped forceps
briefly in the flame and remove the
sterile membrane filter (with the
yellow interleaving disc) from the
package. Using one hand,
remove the stainless steel funnel
with the lid from the base of the
filter holder, and use your other
hand to centre the membrane filter
(with the protective yellow
interleaving disc) on the filter
support.
i) Remove the protective yellow disc
and replace the funnel on the base
of the filter holder. Lock the funnel
in place using the clamp (just lightly
push down on the quick-lock clamp
to secure the parts; there is no
need to force the clamp down to
it's full extent).
3.5 Pour the sample to be tested into
the funnel. For samples less than 5
ml, use 10 to 20 ml of sterile water or
physiological saline as diluent. Re-
open the valve (turn to 6 o'clock) to
suction off the liquid, then close the
valve (turn to 9 o'clock).
3.6 Remove the funnel and using the
flamed, blunt-tipped forceps, remove
the membrane filter.
3.7 Place the membrane filter on a
Nutrient Pad or an agar plate and
incubate. Make certain no air
bubbles are entrapped between the
membrane and Nurtient Pad.
3.8 The filter holders and components
should be rinsed them with 70%
alcohol and air-dry for storage.
3.9 The grid printed on the
membrane facilitates evaluation of
the colony count. The grid optically
divides the filtration surface into 130
squares, each measuring 3.1 x 3.1 mm.
Therefore, one square equals 1/130
of the overall area (if you use the
6980103 stainless steel filter support
with a diameter of 47 mm, available
as an accessory, the filtration area is
2
reduced to 9.6 cm hence, one grid
square equals 1/100 of the 9.6 cm
Important Note: Prefiltration
Samples with a high particle load of
dirt or insoluble sediment must be
prefiltered for bacteriological testing.
The stainless steel prefilter attachment
(16807) (which also can be flamed)
allows you to perform prefiltration in
concurrently with membrane filtration.
Attach it between the stainless steel
funnel and the base and fill
completely with sterile water (to
prevent air from being entrapped and
interfering with filtration), and insert a
12301-050 bacteriological prefilter
(8 µm pore size). This prefilter retains
any coarse particles in the sample,
reducing the particulate load on the
membrane filter on the stainless steel
filter support. Colonies are able to
grow unimpeded by interfering
deposits. The prefilter attachment can
also be flamed.

4. Analyses

4.1 Assemble the filtration system as
described in Sections 2 and 3. A
Minisart SRP25 should be used a a
particle trap during filtration to prevent
exposure of the membrane underside
and filter support to secondery
contamination with particles.
If particle contamination is irrelevant
for your application, close off the
Minisart outlet with a luer lock
(male) plug.
4.2 If applicable, rinse any particles
off the filter holder, the membrane
filter and the blunt-tipped forceps.
4.3 Remove the corresponding
funnel from the base of the filter
holder, and using the blunt-tipped
forceps place the membrane filter on
the filter support.
4.4 Place the funnel back onto the
base of the filter holder, and lock the
funnel in place with the clamp (just
lightly push down on the quick-lock
clamp to secure the parts; there is no
2 need to force the clamp down to it's
).
full extent). BioSart 250 funnels can
be locked in place by turning
clockwise.