Volumetric Glassware from DWK Life Sciences
ISO/IEC 17025 Accreditation
DWK Life Sciences manufactured volumetric products are tested and calibrated in an ISO/IEC 17025 accredited calibration laboratory located at DWK Life Sciences’s glass manufacturing facility in Stoke-on-Trent. To receive ISO/IEC 17025 accreditation, a calibration laboratory must demonstrate the highest levels of competency in a number of areas of its calibration procedures, including:
Certification of Volumetric Products
Many of our volumetric products are available with certification for conformity or traceability purposes. Below is an overview of the certification that is offered by DWK Life Sciences:
UKAS Certified Products
A range of volumetric flasks and measuring cylinders are available with individual UKAS (United Kingdom Accreditation Service) calibration certificates. As well as detailing the measured volume (at 20℃) and uncertainty of measurement, UKAS calibration certificates also include information on the calibration laboratory environmental conditions (in which the product calibrated) and calibration equipment and procedures used. For example, PYREX® measuring cylinders are calibrated at five points on the graduated scale. i.e. a 250ml cylinder will be graduated at 50, 100, 150, 200 and 250ml.
Works Certified Products
Class A/AS Works Certified volumetric products are inscribed with an individual serial number and are supplied with an individual calibration certificate. Each certificate includes details of the actual volume, uncertainty estimation for the calibration and the required tolerance for compliance.
Batch Certified Products
Recalibration of Volumetric Glassware
Normally, volumetric glassware only needs recalibrating after extensive or demanding usage, which may have affected the original accuracy.
Recalibration is usually not necessary if:
However, recalibration should definitely be considered under the following circumstances:
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Frequently Asked Questions
We’ve listened to customers and designed our pipettes with a colored ring marking at its upper end to make selection quick and easy. This color-coding is carried out according to DIN 12621.
All of our pipettes are used for precise volume measurement and are similar in shape to tubes. The difference between graduated pipettes and bulb pipettes lies in the shape and type of graduation. With bulb pipettes, only the total volume can be read off (there is no partial graduation). Graduated pipettes, however, are characterized by partial scaling, where partial volumes can be measured in addition to the total volume.
According to DIN, EN, and ISO, volumetric instruments are divided into two accuracy classes with a fixed error limit.
Here’s a quick guideline: Accuracy Class A always designates the highest accuracy with the
lowest error limit. For accuracy Class B, the double error limits of A/AS generally apply. For volumetric instruments of Class AS, calibrated to "EX", the suffix S indicates rapid execution. This accuracy variant is used for pipettes and Burets.
We’re happy to offer guidance here as cleaning and care are critical. Volumetricinstruments should be cleaned immediately after use either manually in an immersion bath or mechanically in a laboratory dishwasher. Make sure that the cleaning temperature is low, the residence time is short, and the alkalinity of the cleaning medium is also low. Volumetric instruments can then be dried (at max. 250°C) and autoclaved, disinfected, or sterilized.
The use of abrasive cleaning methods is not recommended at any time as this can damage the surface. Cleaning in an ultrasonic bath is possible, however, contact with the sound membranes should be avoided.
Dispensers are piston lifting attachments that can be used to measure defined quantities of liquid easily, quickly, and precisely, for example, from a laboratory bottle. When our dispensers are screwed onto laboratory bottles, the previously set quantity of liquid is sucked into the cylinder by an upward movement of the piston — accurate every time. The subsequent downward movement ejects the quantity of liquid via a cannula. With this principle, there is no need to adjust the meniscus.
For all Class A and AS volumetric instruments there is a retrace code which can be used to
easily download a batch certificate on our website.
No specific certificates are issued for Class B volumetric instruments.