How To Manage Contamination of Your Analytical Balance
App Note / Case Study
Published: February 3, 2025
Credit: Technology Networks
High-resolution balances guarantee the highest level of precision with each measurement. However, they are more susceptible to errors due to contamination by residual substances. Hence, effective cleaning of analytical balances is essential to ensure reliable experimental results.
This application note explores how a new generation of modern analytical balances benefit from hardware and software features that make cleaning processes easier and safer.
Download this application note to discover how to:
Implement best practices for analytical balance cleaning Configure analytical balances according to the needs of your lab Integrate the cleaning process into your compliance procedures and SOPs
Application Note
Find out more: www.sartorius.com
Keywords:
Lab balances, Cleaning, Weighing, Compliance,
contamination, cleaning validation, analytical balance,
weighing pan, draft shield, residue, spill over, accuracy,
digital documentation, high-capacity micro balance,
GxP compliance
Best Cleaning Practices For
Cubis® II Balances
Important Considerations on How to Manage Contamination
Of Your Sartorius Balance
Introduction
The cleaning of a laboratory instrument could be part of
your daily routine or even part of your validation process
or your SOPs. When it comes to laboratory balances, the
higher the resolution of the balance, the greater is the risk
of compromised weighing accuracy due to contamination
from small amounts of leftover residues. This can directly
impact the outcome of your weighing results and the quality
of your samples. However, users often feel insecure about
how to clean their balances properly. Recent developments
tackle this problem in the new generation of Cubis®
II
Ultra-High Resolution Balances from Sartorius. Both
hardware technology and software design were optimized
which made the cleaning process easier, safer and more
efficient.
2
Cleaning Workflow
The preinstalled Cleaning App on our Cubis® II Balances provides an illustrated and guided workflow for cleaning. The App
differs between two cleaning routines:
1. Daily Cleaning on a regular or daily basis
2. Advanced Cleaning during your in-depth maintenence.
Find the examplary workflows for Cubis II Ultra-High Resolution Balances below.
Daily Routine: Keep Your Device Clean on a Regular Basis
The below described steps are recommended on a daily basis, after user logout or when changing the weighing task.
Preparation:
1. Put your balance in standby mode
2. Remove the tools from your cleaning kit (part of your packaging)
3. Pepare paper tissues and cleaning reagents (we recommend water or 70% ethanol)
Balance Disassembly and Cleaning:
1. Remove the weighing pan and clean it with a brush than reinsert
2. Wipe the base plate with the soft brush or wet tissue to ensure there are no residues
left on this area
Key Discussion Points
- Cleaning Workflow: daily and extensive
- How the cleaning app offers intuitive guidance and maintains records?
- How can the cleaning process be part of your compliance and SOPs?
- What parts of the balance can be removed?
- What chemicals can be used?
- Do´s & Don´ts, our recommendations
3
Extensive Cleaning: Schedule Your In-Depth Device Maintanence
In-depth cleaning is recommended at least on a quarterly basis or in case significant spill-over occurs.
Info Cleaning App:
Every Cubis® II Balance with an MCA display comes with a cleaning app. Just click-on the app
for an intuitive in-built guidance and to capture the cleaning event related data digitally.
Preparation:
1. Put your balance in standby mode
2. Remove the tools from your cleaning kit (part of your packaging)
3. Pepare paper tissues and cleaning reagents (we recommend water or 70% ethanol)
Balance Disassembly:
Disassemble all removable parts in the following order:
1. Unclip the display from the base and slide the display towards yourself for enough space
2. Remove the draft shields: 1. Front shield, 2. Left and right draft shield, 3. Upper drafshield
3. Weighing pan and base plate
Balance Cleaning:
Clean the removed parts and the balance itself usig a wet tissue and the tools from the Cleaning
Kit. Keep the following in mind:
- Collect larger amounts of liquid or powder using a tissue, prush or foreceps
- Try to push the samples into the corners of the weighing chamber to avoid they enter any openings
- Metal parts can even be cleaned in the dishwasher
Balance Reassembly:
Ensure all parts are dried completely. Reassemble in the following order:
1. Base plate and weighing pan
2. Upper draft shield, the left and right draft and front panel
3. Display
Balance Tests:
To ensure the proper function of the balance we recommend the following tests/procedures:
1. Function of the draft shield without scratching over the complete range
2. Automatic motorized leveling
3. Internal calibration and adjustment (isoCAL)
4
How the Cleaning App Offers Intuitive Guidance
And Maintains Records?
Every Cubis®
II MCA Balance comes with the Cleaning
Application that with its in-built guidance makes the
cleaning process more intuitive and hassle free. We offer
two types of cleaning procedure, for regular daily cleaning
and for scheduled deep cleaning.
The basic cleaning is recommended on a daily basis, or
before user logout. This process ensures that sample traces
are completely removed avoiding weighing inaccuracy and
sample contamination.
Figure 1 and 2: Example Screenshots Representing the Basic Cleaning Process in a Few Simple Steps.
The advanced cleaning procedure is useful when more
comprehensive cleaning process is required. We recommend this process to be part of your device maintenance
routine and shall be performed at least on a quarterly basis.
It is recommended that a laboratory balance should be
regularly cleaned to ensure, product traces are completely
removed before a new weighing workflow is started.
Figure 3 and 4: Example Screenshots Representing the Advanced Cleaning Process for Deep Cleaning.
The interval of the respective cleaning procedure as well as
the contamination criterion can be adapted to the user’s
needs. The balance can be configured to actively trigger
the respective cleaning workflow by displaying the
contamination status prominently in the status center or
recommending for a cleanup before logout. At the same
time function tests assure the weighing performance after
the cleaning process is completed which further ensures a
proper cleaning process.
5
How Can the Cleaning Process Be Part of Your
Compliance And SOPs?
In recent years, cleaning validation guidelines have become
as complex as process validation due to the raising concerns
over the quality of the cleaning. For those laboratories, where
tracing is required, we offer built-in cleaning workflows (basic
cleaning and advanced cleaning) which can be configurated
according to the need/frequency/user, and most importantly,
the cleaning related events are captured digitally and part of
the audit report. Combined with the QApp Pharma Package
the cleaning process can be signed with an electronic
signature. This enables to keep accurate records of your
cleaning tasks and therefore be part of your compliance or
to your SOPs.
What Chemicals Can Be Used?
Chemical Compatibility
Sartorius balances are long lasting instruments.
The selection of materials is driven by meeting highest
requirements in terms of weighing performance as well es
chemical compatibility. The latter ensures that contamination
does not easily damage your balance and the respective spill
over can be easily removed using various cleaning agents
and solvents.
For cleaning of the balance, we recommend the following
cleaning agents that are compatible with all parts shown in
the previous chapter:
- Water
- Ethanol (70 %)
- Isopropanol (70 %)
Table 1: Detailed Chemical Compatibility for Ultramicro- and Microbalances*
Part of the balance Ethanol
70%
Isopropanol
70%
Acetone
100%
Citric acid
10%
Hydrogen
peroxide
3.5%
Sodium
hydroxide
32%
Klercide
Sporicidal
Chloride
Draft shield + + + + + - +
Filter draft shield + + + + + - +
Filter draft shield lid + + + + + o +
Weighing pan (normal and filter) + + + + + o +
Bush + + + - - - +
Internal draft shield (Ultra Micro) + + + + + - +
Shield plate + + + + + - +
Display + + + + + + +
Palm keys + + - + + - +
Weighing chamber + + + - - - +
Housing + + - + + + +
IR Sensor + + + + + o +
Draft shield back panel + + + + + + +
LED light strip + o + o + - +
E-Box + + - - - - -
Symbol Meaning
+ Well resistant
o Partially resistant (optical changes without affecting the mechanical stability may occur)
- Not resistant
* Avoid contact of any cleaning agent with attached labels as these can be removed or destroyed
6
Table 2: Detailed Chemical Compatibility for Cubis® II High-Capacity Micro Balance and Semimicrobalances Gen. 3
(i.e. MCA225-3S00-D QP99 HWL)*
Part of the balance Ethanol
70%
Isopropanol
70%
Acetone
100%
Citric acid
10%
Hydrogen
peroxide
3.5%
Sodium
hydroxide
32%
Klercide
Sporicidal
Chloride
Upper draft shield + + + o o - o
Draft shield left/right + + - o o - +
Front panel + + + + + - +
Weighing pan + + + + + o +
Adaptor ring + + + + + o +
Base plate + + + + + o +
Back panel o + + + + + +
Display + + + + + + +
Palm keys + + - + + - +
Weighing chamber + + + + + + +
Rear housing (plastic) + o + + + + +
Rear housing (heat sink) + o o + + + +
Inner draft shield glass
cylinder + lid
+ + + - o - +
Back panel inner draft shield + + + + + o +
Inner draft shield base + + + + + o +
Table 3: Detailed Chemical Compatibility for Analytical and Semimicro Balances Gen. 2 (i.e. MCA225S-2S00-A QP99)
Part of the balance Ethanol
70%
Isopropanol
70%
Acetone
100%
Citric acid
10%
Hydrogen
peroxide
3.5%
Sodium
hydroxide
32%
Klercide
Sporicidal
Chloride
Upper draft shield + + + + + - +
Draft shield left & right pane + + + + + - o
Draft shield frame + + + + + - +
Shield plate + + + + + + +
Front shield + + + + + - +
Draft shield back panel + + + + + - +
Rear wall (housing) + + - + + - +
Weighing pan + + + + + + +
Base plate + + + + + + +
Display + + + + + + +
Palm keys + + - + + - +
Weighing chamber + + + - - - +
Housing + + - + + - +
Symbol Meaning
+ Well resistant
o Partially resistant (optical changes without affecting the mechanical stability may occur)
- Not resistant
* Avoid contact of any cleaning agent with attached lables as these can be removed or destroyed.
7
Table 4: Detailed Chemical Compatibility for Precision Balances*
Part of the balance Ethanol
70%
Isopropanol
70%
Acetone
100%
Citric acid
10%
Hydrogen
peroxide
3.5%
Sodium
hydroxide
32%
Klercide
Sporicidal
Chloride
Weighing pan + + + + + + +
Shield plate + + + + + + +
Base plate + + + - - - -
Weighing chamber + + + - - - -
Display + + + + + + +
Housing + + - + + - +
Symbol Meaning
+ Well resistant
- Not resistant
* Avoid contact of any cleaning agent with attached labels as these can be removed or destroyed
Table 5: Detailed Chemical Compatibility for High Capacity Balances*
Part of the balance Ethanol
70%
Isopropanol
70%
Acetone
100%
Citric acid
10%
Hydrogen
peroxide
3.5%
Sodium
hydroxide
32%
Klercide
Sporicidal
Chloride
Weighing pan + + + + + + +
Pan retainer + + + - - - -
Base plate + + + + + - +
Display + + + + + + +
Housing + + - + + - +
Symbol Meaning
+ Well resistant
- Not resistant
* Avoid contact of any cleaning agent with attached labels as these can be removed or destroyed
8
Do’s & Don’ts, Our Recommendations
How to Handle the Balance Parts?
To avoid any parts of the balance from breaking, it is
recommended to handle them with care. Especially the
parts of the draft shield can be damaged rather easily
while uninstalled.
Be sure to have enough place around your balance before
starting the cleaning procedure to keep the balance parts
somewhere safe while taking care of the contamination.
How to Handle Sample Spilling?
Be careful to avoid to not push liquids or solids in any
openings as it can cause severe damage to the weighing
system.
In case you have spilled sample in the weighing chamber,
try to collect it in the chambers corners or carefully absorb
it with a tissue.
Why Is Drying of the Parts Important
After Cleaning?
In case you have used cleaning agents or rinsed these parts
under water, it is extremely important to dry them properly
before reassembly.
A wet weighing pan, sample holder and adapter ring (if
applicable) can lead to moisture entering the weighing
system and can cause drifts in weighing results due to
evaporation or even severe damage.
How to Handle the Ionizer Nozzles?
Be careful to avoid cleaning the ionizer nozzles. These
nozzles can be easily damaged.
When to Call Service?
- If large amounts of liquids or solids entered any openings
on the balance.
- If the rails of the draft shields are already dirty and
movement is limited.
- If any parts break during the cleaning procedure.
Sartorius Instrument Service: https://www.sartorius.com/en/
services/instrument-service/
Germany
Sartorius Lab Instruments GmbH & Co. KG
Otto-Brenner-Straße 20
37079 Göttingen
Phone +49 551 308 0
USA
Sartorius Corporation
565 Johnson Avenue
Bohemia, NY 11716
Phone +1 888 OCTET 75
Or +1 650 322 1360
For further information, visit
www.sartorius.com
Specifications subject to change without notice. ©2023. All rights reserved. All names of Sartorius products are registered trademarks and the property
of Sartorius AG and/or one of its affiliated companies. Cubis-II-Ultra-High-Resolution-Best-Cleaning-Practices-Guide-en-L-Sartorius Status: 12 | 2023