1. No category

User Guidelines & Standard Operating Procedure
for the
AMINCO French Press
French Press Standard Operating Procedure
ii
TABLE OF CONTENTS
DISCLAIMER ................................................................................iii
ACKNOWLEDGEMENTS .................................................................... iv
1.
INTRODUCTION........................................................................1
1.1
Purpose of the Standard Operating Procedure .............................1
1.2
Theoretical Background ........................................................1
1.3
Instrumentation .................................................................2
2.
POTENTIAL HAZARDS.................................................................6
3.
PERSONAL PROTECTIVE EQUIPMENT ...............................................6
4.
SPILL AND ACCIDENT PROCEDURES ................................................7
4.1
Accidents .........................................................................7
4.2
Spills ..............................................................................7
5.
WASTE DISPOSAL PROCEDURES .....................................................9
6.
PROTOCOL........................................................................... 10
6.1
Caring for the French Press and Pressure Cells........................... 10
6.2
Preparing Your Sample ....................................................... 10
6.3
Filling the Pressure Cell...................................................... 12
6.4
Pressurizing the Cell.......................................................... 13
6.5
Cleaning the Cell.............................................................. 15
7.
PREVENTATIVE MAINTENANCE .................................................... 16
7.1
French press ................................................................... 16
7.2
40K French pressure cell..................................................... 16
7.3
Long term storage ............................................................ 16
8.
QUICK REFERENCE GUIDE.......................................................... 17
9.
REFERENCES ......................................................................... 19
9.1
Methodology References ..................................................... 20
APPENDIX 1: FRENCH PRESS USER LOG ............................................... 21
French Press Standard Operating Procedure
iii
DISCLAIMER
The materials contained in this document have been compiled from sources
believed to be reliable and to represent the best opinions on the subject. This
document is intended to serve only as a starting point for good practices and
does not purport to specify minimal legal standards. No warranty, guarantee,
or representation is made by Laurier as to the accuracy or sufficiency of
information contained herein, and Laurier assumes no responsibility in
connection therewith.
French Press Standard Operating Procedure
iv
ACKNOWLEDGEMENTS
The following individuals of Laurier contributed to the writing, editing, and
production of this manual: Gena Braun (Instrumentation Technician); Stephanie
Kibbee (Environmental/Occupational Health and Safety Office).
This manual was prepared for Laurier. Any corrections, additions or comments
should be brought to the attention of the Instrumentation Technician at
519-884-0710 ext. 2361.
Issued: November 2007
Revision: 0
French Press Standard Operating Procedure
1
1. INTRODUCTION
1.1 Purpose of the Standard Operating Procedure
This standard operating procedure (SOP) is NOT a substitute for training
and/or reading the appropriate manuals before use. All principle
investigators and supervisors must document that training has been
received by students and staff who will be using the French Press.
This SOP is intended to promote consistent and safe use of the AMINCO French
press within the Faculty of Science. This SOP covers the potential hazards,
personal protection requirements, spill and accident procedures, waste
disposal considerations, and instrument operation for the AMINCO French press
[henceforth referred to simply as the French press].
1.2 Theoretical Background
The French pressure cell was first developed by C.S. French and H.W. Milner in
1955 (French and Milner, 1955). It has since become a commonly used method
for cell disruption or subcellular fractionation, enzyme preparation, bacterial
and plant tissue degradation, and recovery of intercellular proteins and nucleic
acid. The pressure-induced process results in a more uniform and complete
disruption than usually obtained with other mechanical and ultrasonic methods.
The French press operates at pressures up to 40,000 psi (with the pressure cell
currently available). Samples placed into the cell are pressurized and then
slowly released through a small orifice or outlet valve. As the sample passes
thought the outlet valve, cells and organelles are subjected to a sudden drop in
pressure and the resulting shear stress causes the cells to burst. Following
pressure treatment, the resulting solution is usually centrifuged to separate the
cell components and membrane fragments.
2
French Press Standard Operating Procedure
1.3 Instrumentation
The French press system is composed of a hydraulic press and a 40K pressure
cell. The various components of the press and pressure cell are outlined in
Figures 1-1 and 1-2, and described in Tables 1-1 and 1-2.
Upper platen
Cell clamp
Aligning pins
Cell clamp support rods
Lower platen
Pressure
gauge
Hydraulic
reservoir
access door
Pressure
increase
control
Pump switch
Ratio selector
Figure 1-1: French press components
3
French Press Standard Operating Procedure
Piston
Handle
Flow valve assembly
Handle
O-ring
Cup PT
setscrew
35 ml/Max fill line
Back-up ring
Cell body
Invert ring
Valve stem
O-ring
Back-up ring
Sample outlet
tube
Closure plug
Figure 1-2: Pressure cell components
French Press Standard Operating Procedure
Table 1-1: French press components
Components
Description
Upper platen
Provides a mechanical stop for the top of the
pressure cell piston. Used also in conjunction
with the spacer and piston retainer (not
supplied) for positioning and housing these
components when the rapid-fill pressure cells
are used in the press.
Cell clamp with thumb
screws
Locks top of pressure cell in position to ensure
proper cell alignment during pressurization.
Aligning pins
Centers the cell in the press.
Cell clamp support rods
Provides support for the cell clamp. Remove
rods, install rod extensions, replace rods for use
with the 40K Cell.
Lower platen
Moves up or down to permit cell installation and
subsequent pressurization to selected psi value.
Three alignment pins on lower platen are used
to position lower section of cell body in press.
Pressure gauge
Indicates pressure value at RATIO SELECTOR
valve. The actual pressure value applied to
lower platen depends upon the position of
RATIO SELECTOR lever (HIGH, MED or DOWN).
Pressure increase
control
Used in conjunction with RATIO SELECTOR
control lever to regulate amount of pressure
applied to lower platen (item 7). Clockwise
rotation increases pressure, while
counterclockwise rotation decreases pressure.
Pump switch
Controls application of AC power to pump motor
inside unit.
Ratio selector
MED or HIGH position is used in conjunction with
PRESSURE INCREASE CONTROL to control
pressure against lower platen (item 7). DOWN
position permits lower platen to descend for
pressure cell installation or removal.
Hydraulic reservoir
access door
Opens to gain access to hydraulic fluid reservoir
inside the press.
4
French Press Standard Operating Procedure
Table 1-2: 40K Pressure cell components
Components
Description
Flow valve assembly
Controls the rate of sample release when the
cell is under pressure.
Handle
Turns clockwise or counterclockwise to
decrease or increase sample flow
respectively. DO NOT OVERTIGHTEN.
Valve stem
Fits into the closure plug base to control
sample flow rate.
Cell body
Contains the sample to be processed, up to a
volume of 35 ml.
Closure plug
Fits into the bottom of the cell body.
O-ring and back-up ring
Insures a tight seal between the cell body
and the closure plug.
Sample outlet tube
Processed sample flows out of this tube
when the cell is under pressure or when the
cell is inverted after filling.
Piston
Transfers pressure from the upper platen of
the press to the pressure cell.
Handle
Used to insert the piston into the cell.
35 mL/Max fill line
The maximum point to which the piston can
be withdrawn from the cell.
O-ring and back-up ring
Insures a tight seal between the cell body
and the piston.
Invert ring
Holds the o-ring and back-up ring in place.
5
French Press Standard Operating Procedure
6
2. POTENTIAL HAZARDS
Do not over-pressurize the cells: Before applying pressure to the cell,
determine the gauge pressure required to produce the desired pressure in the
cell. The maximum working pressure with the cell currently available is 40,000
psi. This corresponds to a maximum gauge reading on HIGH of 2,520 psi. DO
NOT EXCEDE THIS VALUE FOR ANY REASON.
If the maximum working pressure is exceeded, the seals and/or cell itself could
rupture causing serious injury to the operator.
The French press and pressure cells are to be used with samples of plant or
animal cells only. DO NOT put inappropriate materials (e.g., sand, glass, dirt,
etc.) in the cell as this could result in an explosion, causing bodily injury.
The pressure cell must be seated firmly between the aligning pins and flat
on the lower platen before pressure is applied. If the cell is not seated
properly it can be seriously damaged under pressure or potentially ejected
from the press, again presenting a serious hazard to the operator.
Check the condition of all o-rings and cell components before beginning a
run. Damaged o-rings can cause the piston to bend or jam in the pressure cell
or cause leaks during a run.
3. PERSONAL PROTECTIVE EQUIPMENT
Material to be processed may contain potentially infectious
material, so standard laboratory protective equipment must be
worn (latex or nitrile gloves, approved safety glasses or goggles,
and a lab coat).
See the WLU Laboratory Health and Safety Manual for additional
information on personal protective equipment:
http://www.wlu.ca/documents/23120/Laboratory_Health_%26_
Safety_Manual__Feb_2007_Final.pdf.
French Press Standard Operating Procedure
7
4. SPILL AND ACCIDENT PROCEDURES
4.1 Accidents
All incidents must be reported to the Instrumentation Technician and if
applicable, a student’s supervisor.
The Instrumentation Technician will insure that all accidents, incidents and
near misses are reported to the Environmental/Occupational Health and Safety
(EOHS) Office via the WLU Employee Accident/Incident/Occupational Disease
Report form (www.wlu.ca/eohs/forms). To meet regulatory requirements,
these forms must be submitted to EOHS within 24 hours of occurrence, with the
exception of critical injuries, which must be reported immediately to the EOHS
Office by telephone. Critical injuries include any of the following; place life in
jeopardy, produce unconsciousness, result in substantial loss of blood, involve
fracture of a leg or arm but not a finger or toe, involve amputation of a leg,
arm, hand or foot, but not a finger or toe, consist of burns to a major portion
of the body, or cause the loss of sight in an eye.
Additional details regarding incident reporting can be found in the WLU
Accident Incident Procedure (www.wlu.ca/eohs).
4.2 Spills
The WLU Laboratory Health and Safety Manual provides detailed instructions
for dealing with major and minor spills. Do not attempt to clean up a spill if
you have not been properly trained, or if you are unsure of the proper
procedures. Before using ANY hazardous materials, make sure you
understand the proper clean-up procedure. The Environmental/Occupational
Health and Safety Office is also available to provide guidance at ext. 2874. The
guidelines below are summarized from the WLU Laboratory Health and
Safety Manual.
Determine if the spill is a major or minor spill (see Table 4-1).
1. For major spills:
a. Evacuate the lab, close the doors, restrict the area, and notify others in
the area of spill, including your supervisor and the Instrumentation
Technician if possible.
b. Call ext 3333 (Community Safety and Security).
c. Activate the fire alarm if there is risk to the safety of other people in the
building.
d. Be available to provide technical information to emergency responders.
2. For minor spills:
a. Attend to injured or contaminated personnel.
French Press Standard Operating Procedure
8
b. Restrict the area and notify others in the lab of the spill, including your
supervisor and the Instrumentation Technician if possible.
c. Take action to minimize the extent of the spill.
d. If flammable material is involved, turn of ignition sources (power, Bunsen
burners).
e. It is the responsibility of the user of the hazardous material to clean up
the spill if he/she feels it is safe to do so.
f. Select and wear all appropriate personal protective equipment.
g. Apply spill pillow/pads or other absorbent material, first around the
outside of the spill, encircling the material, then absorb to the center of
the spill.
h. Dispose of all materials used to clean up the spill in a sealed container.
i. All personal protective equipment must be disposed of correctly, and
must not be worn outside the laboratory.
j. Label and dispose of all bags or containers as hazardous waste.
3. For chemical spills on the body:
a. Remove all contaminated clothing.
b. Flood exposed area with running water form a safety shower for at least
15 minutes.
c. Have another individual contact 9-911 and ext 3333 to obtain medical
attention.
4. For chemicals splashed in the eye(s):
a. Immediately rinse eyeball and inner surface of eyelid with water
continuously for 15 minutes. Forcibly hold eye lid(s) open to ensure
effective wash behind eyelids.
b. Have another individual contact 9-911 and ext 3333 to obtain medical
attention.
5. IN ALL CASES: Report the incident to your supervisor and the
Instrumentation Technician.
9
French Press Standard Operating Procedure
Table 4-1: Guidelines for classification of a major spill
Material
Quantity
Air and water reactive materials
All quantities
Flammable liquids
Greater than 4L
Combustible liquids
Greater than 4L
Non-flammable organic liquids
Greater than 4L
Concentrated acids
Liquids greater than 1L
Solids greater than 1kg
Concentrated bases and alkalis
Liquids greater than 1L
Solids greater than 1kg
Mercury
Greater than 30 ml
Oxidizers
Liquids greater than 1L
Solids greater than 500g
Highly toxic, highly malodorous
material
Liquids greater than 100 ml
Solids greater than 50g
Low hazard material
At the discretion of laboratory
personnel
Compressed gas leaks
If the leak cannot be stopped by
closing the valve on the gas cylinder
5. WASTE DISPOSAL PROCEDURES
Any hazardous chemicals or biological materials used for sample analysis or
preparation must be disposed of properly, as outlined in the WLU Laboratory
Health and Safety Manual and the WLU Biosafety Manual.
French Press Standard Operating Procedure
10
6. PROTOCOL
6.1 Caring for the French Press and Pressure Cells
1. Never use any corrosive solutions in the cell. This includes all acidic and
mildly acidic solutions, such as acetate.
2. Check the condition of the o-rings on the piston before and after each use.
If either o-ring looks worn (nicked, or black material comes off when you
touch it) call the Instrumentation Technician to have the o-ring replaced. A
broken o-ring can cause the piston to get stuck and render the pressure
cell useless.
3. Handle the piston with care to avoid scratching it. Do not put it down on the
bench top. Place it on clean kimwipes or a similar soft clean surface when
not in use. Store wrapped in a soft clean cloth.
4. Do not use a hard bristle brush on any part of the French press. Clean only
with a soft towel or kimwipe.
5. Check the oil level. With the unit off and unplugged, open the side door
and remove the reservoir cap. Check the level of hydraulic fluid in the
reservoir, and contact the Instrumentation Technician if the level is near or
below the minimum line.
a. If the press will be operated below 20oC a different type of hydraulic
oil must be used; contact the Instrumentation Technician.
6.2 Preparing Your Sample
1. The bacterial suspension should not be too thick. The ideal suspension has
10 g (wet weight) of cells per 100 ml of buffer. The maximum concentration
is 15 g cells per 100 ml of buffer.
2. See Table 6-1 for examples of solutions and pressures used to disrupt
different cell types in a French pressure cell.
11
French Press Standard Operating Procedure
Table 6-1: Solutions and pressures used in French pressure cells.
Isolated fraction
Neisseria
meningitidis
transferrin-binding
proteins(1)
Buffer used
0.1 M acetate buffer, 0.2 M
lithium chloride, pH 5.8 (LiCl
buffer)
Working
Pressure
(psi)
Number
of passes
through
the press
16,000
Three
Incubated for 2 hours at 45oC in
a shaking water bath
Cyanidioschyzon
merolae
chloroplasts(2)
Hypotonic solution: 20mM trisHCl (pH 7.6), 5 mM MgCl2 5mM
KCl, 5mM EGTA) containing 180
mM sucrose
1,500
Not stated
Rhodobacter
sphaeroides
chromatophores(3)
Not stated.
21,755
(150 mPa)
Not stated
Acaryochloris
marina chlorophyll
d(4)
Tricine, 20 mM KCl, 0.05% NaN3
10,442
(72 MPa)
Not stated
Nicotiana glauca
guard cell protein(5)
250 mM sucrose, 50 mM TrisHCl (pH 7.5), 5 mM
EDTA, 5 mM DTT, 2 mM PMSF
with 2%
polyvinylpolypyrrolidone
18,000
Two
French Press Standard Operating Procedure
12
6.3 Filling the Pressure Cell
During the assembly and fill process, do not allow the piston to pick-up
granules (e.g., sand, glass, dirt, etc.). A contaminated piston will
irreversibly damage the inside of the cell.
1. Make sure that the piston and the closure plug can be inserted and removed
smoothly from the cell. If not, a small amount of Dow Corning silicon grease
may be applied to the o-rings (this grease can be obtained from the
Instrumentation Technician). Do not apply any grease if not required.
2. Slide the piston into the cell to a small volume line (the minimum volume is
5 mL)
3. Invert the cell and piston and place on the cell filling stand (see Figure 6-1).
Figure 6-1: Pressure cell inverted in the filling stand
4. Fill the pressure cell with straight buffer first as follows:
a. Make sure the buffer is free of any debris or particulate. Small particles,
including broken pipette tips, will scratch the inside of the cell.
b. With the piston in place and the cell inverted on the filling stand, pour a
small volume of buffer into the cell (5-10 mL). Fill to within 1” of the
bottom of the cell to minimize any air trapped in the cell. Trapped air will
be expelled under high pressure when the cell is pressurized, and can
cause splattering and loss of sample.
c. Place a waste beaker close to the filling stand to catch any flow out for
the outlet tube. Make sure that the outlet valve is open slightly to allow
air and excess buffer to escape, and gently push the close plug onto the
bottom of the cell. CAUTION: Some liquid will drip out of the cell as the
closure plug is put in place. Orient the outlet tube and waste beaker to
catch this liquid.
13
French Press Standard Operating Procedure
d. Tighten the outlet valve. Make sure that the outlet valve handle is only
finger tight; over tightening the valve can damage the seal.
5. With one hand on the closure plug, and one hand on the cell body, carefully
lift the filled cell out of the filling stand and invert it.
6. Place a waste beaker underneath the outlet tube, and open the outlet
valve.
7. Gently press down on the piston to expel the buffer from the cell, and in
doing so, rinse out the cell.
8. Repeat steps 4 and 5 using the desired volume of sample (maximum
volume of 35 ml).
6.4 Pressurizing the Cell
1. Place the filled cell onto the lower platen of the French press. Make sure it
is properly seated between the aligning pins on the lower platen (Figure 62).
Cell clamp
Cell clamp
support rods
Outlet valve
Rod extensions
Sample outlet
tube
Figure 6-2: Pressure cell installed on the French press
2. Double check to make sure the closure plug is properly in place and the cell
is seated firmly between the aligning pins. If the closure plug slips out and is
not completely seated in the cell when you start to apply pressure, you may
bend it and possibly, if the cell surfaces are not 100% horizontal, shoot the
cell out of the press. This can also occur if the cell is overfilled and the
piston is not inserted properly.
3. Secure the cell in place with the cell clamp.
4. Make sure that the piston handle is perpendicular to the cell clamp thumb
screws; otherwise the piston handle may hit the thumb screws when under
French Press Standard Operating Procedure
14
pressure and deform the handle. Hand tighten the thumb screws to keep
the cell from rising up when pressure is applied.
5. Use the table printed on the front of the press to assess the desired working
pressure and corresponding gauge pressure. Do not set the working pressure
above 40,000 psi. The corresponding maximum gauge pressure with the
RATIO set on high is 2,520 psi. If the maximum working pressure of the
cell is exceeded, the seals and/or cell itself could rupture causing serious
injury to the operator.
6. Plug in the French press.
7. With the pump off: Turn the PRESSURE INCREASE control fully
counterclockwise and set the RATIO SELECTOR to DOWN.
8. Set the PUMP switch to on and turn the PRESSURE INCREASE control
clockwise until the gauge indicates the pressure selected in step 5.
a. Be patient: It may take a few moments for the pump to fill and pressurize
the internal hydraulics of the press.
9. Set the RATIO SELECTOR to either MED or HIGH. The position of this level is
also determined by the pressure selected in step 5.Check the cell alignment
in the press as the lower platen rises. Ensure that the cell piston squarely
strikes under the upper platen.
a. If the pressure cell needs to be realigned lower the platen by placing
the three-position control lever to DOWN. Realign the cell in the press.
10.Recheck the psi reading on the pressure gauge to ensure that it indicates
the predetermined pressure value.
a. Do not adjust the pressure when the cell itself is under pressure (i.e.
the platen is set at MEDIUM or HIGH). If the pressure needs to be
readjusted, first set the RATIO SELECTOR to DOWN and wait for the platen
to reach its lowest position.
11.Open the flow valve on the cell only slightly so liquid flows from the sample
outlet tube at a rate of approximately 15 drops per minute (1 drop every 4
seconds). This is the maximum recommended flow rate.
a. The flow valve is extremely sensitive. To achieve the desired flow rate,
gently finger tap the valve handle.
12.Some air may be present in the cell; be prepared for a slight "spitting"
action at the end of a run. It's best to hold the outlet tubing during the
process. After the sample has been processed, lower the platen by placing
the RATIO SELECTOR control lever to DOWN.
a. There will be some sample loss due to material left in the valve ports and
drip tube. Do not try to squeeze out the last drop sample. You will
damage the piston, closure plug and cell body.
13. Unless you are doing other tests, when the platen reaches its lowest
position, reduce the system pressure to zero by turning the PRESSURE
INCREASE control fully counterclockwise. Then set the pump switch to OFF.
14.Open the outlet valve completely to release any pressure remaining in the
cell.
15.Remove the cell from the press when all the processing is complete. Clean
and store the Pressure Cell as described in section 6.5.
French Press Standard Operating Procedure
15
16.Check the exterior of the press. Wipe any hydraulic fluid or sample spills
from the press surface using a damp cloth. Do not use solvents.
17. Fill in the log book.
6.5 Cleaning the Cell
DO NOT STORE THE PRESSURE CELLS ASSEMBLED.
Clean and dry the pressure cells thoroughly after each use. All metal parts
are made of 400-series stainless steel (specially heat-treated) and are
susceptible to surface corrosion if not properly cleaned and dried.
If you sample is a BIOLOGICAL HAZARD, you must COLLECT all of the rinse
water from the following steps, and autoclave it along with the cell, piston,
and closure plug. Do not autoclave the outlet tube as it may melt (rinse briefly
with the dilute bleach found in the French press cupboard, and then thoroughly
rinse with water).
1. When you are done, you must carefully rinse out the cell to prevent
corrosion. The cell, just like an ultracentrifuge rotor, will corrode if not
thoroughly cleaned.
2. Disassemble the cell and rinse all pieces with running water. A small
amount of gentle soap can be used, but it must be rinsed thoroughly.
3. Pay particular attention to rinsing water through the outlet stem and
through the orifices of the cell itself. Slide the closure plug into the cell and
allow water to flow through the valve hole. Cover the valve hole and allow
water to flow through the outlet hole.
4. Allow the cell to air dry on paper towels.
5. Check all o-rings and make sure they are in good condition. Contact the
Instrumentation Technician if they appear worn or damaged.
6. Store the cell away from salt solutions or corrosive substances.
French Press Standard Operating Procedure
16
7. PREVENTATIVE MAINTENANCE
Users are not to perform maintenance. These procedures are carried out by
the Instrumentation Technician.
7.1 French press
-
Replace the fuse as required
Clean the outside of the press with a damp cloth
Check the hydraulic fluid level and replace if necessary
7.2 40K French pressure cell
-
Change the o-rings when the cell leaks or the o-rings are visibly damaged
7.3 Long term storage
-
A light coating of mineral oil should be applied to all surfaces to prevent
corrosion during periods of non-use.
French Press Standard Operating Procedure
17
8. QUICK REFERENCE GUIDE
WEAR PERSONAL PROTECTIVE EQUIPMENT
Safety glasses or goggles, gloves, and lab coat
During the assembly and fill process, do not allow the piston to pick-up
granules (e.g., sand, glass, dirt, etc.). A contaminated piston will
irreversibly damage the inside of the cell.
1. Make sure all cell components (o-rings, piston) are in good condition before
beginning.
2. Check the hydraulic oil level. Refill if needed.
3. Rinse the pressure cell components with a small amount of buffer (use the
cell filling stand).
4. Slide the plunger to the desired volume line (max 35 mL) and fill with
sample using the filling stand.
5. Tighten the outlet valve on the closure plug to hand tight, lift the cell out
of the filling stand and invert the cell using both hands.
6. Place the filled cell onto the lower platen of the French press. Make sure it
is properly seated between the aligning pins on the lower platen and the
closure plug is firmly in place.
7. Secure the cell in place with the cell clamp and hand tighten the thumb
screws.
8. Make sure that the piston handle is perpendicular to the cell clamp thumb
screws; otherwise the piston handle may hit the thumb screws when under
pressure and deform the handle.
9. Use the table printed on the front of the press to assess the desired working
pressure and corresponding gauge pressure. Do not set the working
pressure above 40,000 psi. The corresponding maximum gauge pressure
with the RATIO set on HIGH is 2,520 psi.
10.With the pump off: Turn the PRESSURE INCREASE control fully
counterclockwise and set the RATIO SELECTOR to DOWN.
11.Set the PUMP switch to on and turn the PRESSURE INCREASE control
clockwise until the gauge indicates the pressure selected in step 7.
12.Set the RATIO SELECTOR to either MED or HIGH. The position of this level is
also determined by the pressure selected in step 7.
a. If the pressure cell needs to be realigned lower the platen by
placing the three-position control lever to DOWN. Realign the cell in
the press.
13.Recheck the psi reading on the pressure gauge to ensure that it indicates
the predetermined pressure value. Do not adjust the pressure when the cell
itself is under pressure.
14.Open the flow valve on the cell only slightly so liquid flows from the sample
outlet tube at a rate of approximately 1 drop every 4 seconds.
French Press Standard Operating Procedure
18
15.After the sample has been processed, lower the platen by placing the RATIO
SELECTOR control lever to DOWN. Do not try to squeeze out the last drop
sample.
16. Reduce the system pressure to zero by turning the PRESSURE INCREASE
control fully counterclockwise. Then set the pump switch to OFF.
17.Open the outlet valve completely to release any pressure remaining in the
cell.
18.Remove the cell from the press when all the processing is complete. Clean
and store the Pressure Cell as described in section 6.5 (do not store it
assembled).
19.Check the exterior of the press. Wipe any hydraulic fluid or sample spills
from the press surface using a damp cloth. Do not use solvents.
20.Fill in the log book.
French Press Standard Operating Procedure
19
9. REFERENCES
International Livestock Research Institute. www.ilri.org. Accessed August 15,
2007.
The David Bird Laboratory. Plant Nematode Genetics Group. North Carolina
State University. www.cals.ncsu.edu. Accessed August 15, 2007.
Laboratory Health and Safety Manual. 2007. Wilfrid Laurier University
Environmental/Occupational Health and Safety Office.
Marcus SL. French Press Mini-Cell Protocol. Biological Services, Department of
Chemistry, University of Alberta. www.chem.ualberta.ca/~bioservices.
Accessed August 15, 2007.
Vanderheiden GJ, Fairchild AC, Jago GR. 1970. Construction of a laboratory
press from use with the French pressure cell. Applied Microbiology, 19: 875877.
French CS, Milner HW. 1955. Disintegration of bacteria and small particles by
high-pressure extrusion, p. 64-67. Colowick SP, Kaplan NO (ed.), Methods in
enzymology, vol. 1. Academic Press Inc., New York.
French Press Standard Operating Procedure
20
9.1 Methodology References
(1) Echeverría B, Gómez JA, Hernández E, Criado MT, Ferreirós C. 1988.
Optimization of membrane isolation and transferrin-binding proteins
solubilization from Neisseria meningitidis cells. Journal of
Microbiological Methods 31: 151-157.
(2) Miyagishima S, Itoh R, Aita S, Kuroiwa S, Kuroiwa T.1999. Isolation of
dividing chloroplasts with intact plastid-dividing rings from a
synchronous culture of the unicellular red alga Cyanidioschyzon
merolae. Planta 209: 371-375.
(3) Tokaji Z, Tandori J, Maróti P. 2002. Light- and Redox-dependent Thermal
Stability of the Reaction Center of the Photosynthetic Bacterium
Rhodbacter sphaeroides. Photochemistry and Photobiology 75: 605–
612.
(4) Chen M, Zeng H, Larkum AWD, Cai Z. 2004. Raman properties of
chlorophyll d, the major pigment of Acaryochloris marina: studies
using both Raman spectroscopy and density functional theory.
Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy
60: 527-534.
(5)
Smart LB, Nall NM, Bennett AB. 1999. Isolation of RNA and Protein from
Guard Cells of Nicotiana glauca. Plant Molecular Biology Reporter 17:
371-383.
French Press Standard Operating Procedure
APPENDIX 1: FRENCH PRESS USER LOG
21
22
French Press Standard Operating Procedure
DATE
NAME
EXT #
SUPERVISOR
SAMPLE TYPE
AND
CONCENTRATION
WORKING/
CELL
PRESSURE
GAUGE
PRESSURE
RATIO
SETTING
PROBLEMS /
COMMENTS
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