Leica RM2125RTS Manual

CONTROLLED COPY
Centre for Biological Engineering
Standard Operating Procedure SOP194
Title: Use and maintenance of Leica RM2125 RTS rotary microtome.
Location: H27
Version 001 Effective Date: 24.05.2021 Review 24.05.2023
Written by: Sotiria Toumpaniari
Reviewed by:
Approved by: C.Kavanagh
Page 1 of 11
1. PURPOSE
To describe the use and maintenance of the Leica RM2125 RTS rotary microtome that is located in the
CL2 CBE laboratory H27.
2. SCOPE
This SOP applies to CBE personnel using the Leica RM2125 RTS rotary microtome for the sectioning
of fixed soft tissues that have been embedded in wax or other hard polymers. The microtome is
assigned to H27 which is used for histological processing and this system should not be transferred to
another lab. Only authorised and trained personnel may use the microtome.
3. RESPONSIBILITES
3.1. Authorised laboratory staff shall:
(i) Work in accordance with the instructions for operation and maintenance detailed in this SOP,
Risk Assessment and the operator manual.
(ii) Carry out the routine inspection, cleaning, and maintenance of the equipment, as required.
(iii) Record any adverse events and alarms that indicate non-conformance or malfunction on the
Maintenance Record and notify the Laboratory Manager/Responsible Person.
3.2. The Responsible Person/Laboratory Manager shall:
(i) Ensure that authorised laboratory personnel are given suitable information, instruction, training
and supervision in the correct use and maintenance of the equipment.
(ii) Investigate any reported problems, adverse event, alarms, or non-conformities associated with
equipment usage.
(iii) Organise the maintenance, repair, or servicing of the equipment by trained and authorised
contract / service personnel.
4. EQUIPMENT AND MATERIALS
1. Leica RM2125 RTS rotary microtome and accessories
2. Blades
3. Brush
4. Appropriate PPE (labcoat, gloves, overshoes and eye protection, where appropriate)

CONTROLLED COPY
Centre for Biological Engineering
Standard Operating Procedure SOP194
Title: Use and maintenance of Leica RM2125 RTS rotary microtome.
Location: H27
Version 001 Effective Date: 24.05.2021 Review 24.05.2023
Written by: Sotiria Toumpaniari
Reviewed by:
Approved by: C.Kavanagh
Page 2 of 11
5. PROCEDURE
5.1. Description of the system
The Leica RM2125 RTS is a manually operated rotary microtome for creating thin sections of
specimens of varying hardness for use in routine and research laboratories in the fields of biology,
medicine, and industry. It is designed for sectioning soft paraffin specimens as well as harder
specimens, as long as they are suitable for being cut manually.
Note: Operating temperature range is 10°–35°C, and relative humidity range is 20-80% non-condensing
humidity. Section thickness range is 0.5- 60μm.
5.2. Overview of components

CONTROLLED COPY
Centre for Biological Engineering
Standard Operating Procedure SOP194
Title: Use and maintenance of Leica RM2125 RTS rotary microtome.
Location: H27
Version 001 Effective Date: 24.05.2021 Review 24.05.2023
Written by: Sotiria Toumpaniari
Reviewed by:
Approved by: C.Kavanagh
Page 3 of 11
5.3. Operation
5.3.1. Clamping specimen on universal cassette clamp
1. Always clamp the specimen block BEFORE clamping the knife or the blade.
2. Lock the handwheel and cover the knife edge with the knife guard prior to any manipulation of knife
or specimen, prior to changing the specimen block and during all work breaks.
3. Activate the handwheel lock by allowing the handwheel handle to lock in place.
4. To insert a specimen into the specimen clamp, puch lever (1) fowrards.
5. Mount the cassette (2) horizontally or vertically as required.
6. To clamp the cassette, release the lever.
Note: Before clamping the cassette into the universal cassette clamp, remove excess wax on the outside of the
cassette to ensure that the cassette clamps in securely.
Wax deposits on the outside of the cassette can make the universal cassette clamp dirty. The dirt prevents the
cassette from clamping in securely and can lead to sections being too thick or thin, chattering within the section
and, in the worst-case scenario, damage to the specimen. Prior to sectioning, the user has to verify that the
specimen is clamped securely and, if necessary, remove wax deposits from the universal cassette clamp.
5.3.2. Clamping the knife / disposable blade in knife holder E
1. Carefully insert knife or disposable blade into the knife holder and clamp.
2. Fold knife guard (3) downward.
3. To insert the blade, rotate clamping lever (4) forward.
4. Carefully push in the blade (5 or 6) from the side.
5. To clamp the blade, rotate clamping lever (4) back upwards.

CONTROLLED COPY
Centre for Biological Engineering
Standard Operating Procedure SOP194
Title: Use and maintenance of Leica RM2125 RTS rotary microtome.
Location: H27
Version 001 Effective Date: 24.05.2021 Review 24.05.2023
Written by: Sotiria Toumpaniari
Reviewed by:
Approved by: C.Kavanagh
Page 4 of 11
5.3.3. Adjusting the clearance angle
1. The index marks (0°, 5° and 10°) for adjustment of the clearance angle (10) are located on the right
side of the knife holder (8).
2. There is also an index mark (11) on the right side of the knife holder base (7) which serves as a
reference point when adjusting the clearance angle.
3. When using the knife holder base (non-orientable), loosen the Allen screw to release the clamp by
turning Allen key No. 4 (9) counterclockwise.
4. When using the knife holder base (with lateral movement), rotate the lever on the right side of the
knife holder base counterclockwise.
5. Move the knife holder until the index mark of the desired clearance angle coincides with the
reference line on the knife holder base.
Example: Enlarged detail showing a clearance angle setting of 5°.
Note: The recommended clearance angle setting for knife holder E is approx. 1° - 3°.
6. Firmly hold the knife holder in this position and rotate the lever (9) or Allen screw (depending on the
knife holder base used) clockwise to clamp it.
5.3.4. Specimen retraction (specimen orientation)
(i) To prevent the knife or blade from touching the overlapped specimen while returning to the upper end
position, the specimen is retracted 40 μm when retraction is activated.

CONTROLLED COPY
Centre for Biological Engineering
Standard Operating Procedure SOP194
Title: Use and maintenance of Leica RM2125 RTS rotary microtome.
Location: H27
Version 001 Effective Date: 24.05.2021 Review 24.05.2023
Written by: Sotiria Toumpaniari
Reviewed by:
Approved by: C.Kavanagh
Page 5 of 11
Note: The user can switch the specimen retraction ON or OFF.
(ii) To do so, use an Allen key with handle, No. 4 (included in the delivery package) and turn the screw
depicted in the detail picture (Fig. 13a) so that the red dot indicates "OFF" = retraction is disabled. Red
dot on "ON" means = retraction is switched on.
(iii) Important if retraction is enabled:
The specimen must NOT be oriented or approached in the retraction phase (if the black dot on the
handwheel is visible – see enlarged detail Fig. 13 – you are in the sectioning phase)! The previously
retracted specimen will advance by the retraction value PLUS the selected section thickness before the
next section.
There is a danger of the specimen and knife being damaged by a section that is too thick.
The same applies to the "rocking mode", during which the specimen is trimmed by rocking motion (no
complete rotation of the handwheel).
Carry out "rocking mode" ONLY in the sectioning phase – NEVER in the retraction phase!
5.3.5. Orienting the specimen
The specimen orientation allows for simple position correction of the specimen surface when the
specimen is clamped into place.
1. Run the specimen to the rear end position by turning the coarse feed wheel.
2. Loosen the clamping lever in front on the microtome base plate and slide the knife holder base with
knife holder until it is almost in front of the specimen.
Note: Specimen blocks must NOT be oriented during the retraction phase!
If a block is oriented during retraction, the block will advance by the retraction value PLUS the selected
section thickness before the next section.
This may cause damage to both specimen and knife!
3. Move the specimen holder fixture to the upper end position by turning the handwheel and engage
the handwheel lock.
4. To release the clamp, turn the eccentric lever (12) counterclockwise.
5. Turn setscrew (14) to orient the specimen in north-south direction. Turn setscrew (13) to orient the
specimen in east-west direction.
6. To lock the current orientation, turn the eccentric lever (12) clockwise.