DWK Life Sciences sets the standard for volumetric pipettes, offering you unparalleled choice and guaranteed accuracy. Our pipette line includes many application-specific
varieties: bacteriological, serological, and measuring pipettes to name a few. In addition, we offer different characteristics to suit specific purposes including glass, plastic, and electronic versions plus a variety of sizes. We stock large quantities of reusable, disposable, and sterile pipettes to meet your immediate needs. To avoid dangerous cross-contamination of valuable specimens or laboratory reagents, our disposable pipettes are recommended.
Frequently Asked Questions
Our 5mL Acura (W810316) and 5mL Acura Electro (W870920-A) will work well with glass
Pasteur pipette tips when used with adapter W820023. Or, if you prefer, our 2mL Calibra
(851340), which comes supplied with an adapter, can be used with Pasteur pipette tips.
Sterilization by means of irradiation may cause cross-linkage or scission of chemical bonds at the molecular level. The amount of scission or cross-linkage is dependent upon chemical composition, morphology, and radiation absorption. These effects may increase or decrease over time. Although the effects of radiation on particular types of material may be predicted, they may also depend upon outside stresses placed in the product during manufacturing or storage after the process, which can lead to brownish discoloration of the glass.
Therefore, we recommend the qualification of materials/products at a dose at or above the maximum dose range followed by product functionality at several time frames throughout the predicted life span of the product. The results of this testing should be used to establish the maximum dose for routine processing.
Pipettes are sterilized at a 25.0-40.0 kGy range based on an AAMI dose validation study
performed by our sterilization vendor. The bioburden test data and the dose calculation from that study determine the dose required.
Only our serological pipettes require that the last drops be "blown out" to obtain the total
rated capacity. They are calibrated to deliver to the tip and are permanently marked in one of two ways: with two bands or a wide opaque ring near the top end. Volumetric (transfer) or
measuring (Mohr) pipettes are calibrated after the touch-off method.
For your reference, we’ve outlined the proper method of delivery below.
- Draw the liquid above the top graduation using a bulb or equivalent device.
- Use your forefinger — not your thumb — for level control.
- Wipe any drops off the outside surface.
- Zero meniscus at the top graduation.
- Dispense in vertical position with unrestricted outflow.
- Touch off the last remaining drop to the surface of the receiver vessel two seconds after free-flow stops.
All calibrated volumetric glassware requires that the user be informed whether the ware is "To Contain" or "To Deliver" and that it be permanently marked "TC" or "TD." When the graduation line denotes the volume contained in the calibrated vessel, it is marked TC. The ware is marked TD when the graduation line indicates the volume delivered from the vessel. TD calibrated vessels are different from the TC calibrated vessels because of the drainage holdback error. For example, when the amount of water required to wet the inner surface of the vessel in contact with the water is added to the TC volume, the TD vessel then delivers the same volume as the contained volume in a TC vessel. Be advised, the International Standards Organization designation for "To Contain" is "IN" and the "To Deliver" is "EX."