The Reference 2 is the successor to the highly successful Reference pipette, and enhances the range’s already high standards with a new design, reduced weight and operating forces and multi-channel versions.
As the premium product in Eppendorf’s pipette portfolio, the Reference 2 provides the most accurate results possible alongside robust, reliable handling and optimum user safety.
These levels of security make the Reference 2 ideal for use with precious liquids, or in any application requiring extremely high levels of accuracy. When there can be no compromise on quality and reproducibility, Eppendorf’s new Reference 2 is an ideal instrument for these liquid handling applications.
Eppendorf Reference® 2 pipettes come in 3 varieties:
Reverse pipetting means uptake of liquid including the blow-out volume and dispensing of liquid without the blow-out volume. Reverse pipetting is recommended to reduce the error with viscous or foaming liquids or when dispensing very small sample volumes. The excess solution aspirated remains in the tip and is discarded.
When pipetting viscous liquids, we recommend positive displacement instruments like Biomaster, Multipette/Repeater, and Varipette or an air cushion pipette (Research plus, Reference 2) in combination with the reverse pipetting technique (see Userguide 20 and 21 for details).
When pipetting chloroform, we recommend positive displacement instruments like Biomaster, Multipette/Repeater, and Varipette or an air cushion pipette (Research plus, Reference 2) in combination with the reverse pipetting technique (see Userguide 20 and 21 for details).
Diethyl ether has such a high vapour pressure that it would leak out of the tip immediately when an air cushion pipette is used. For this reason, it can only be pipetted using a positive displacement pipette, such as Biomaster, Multipette/Repeater, and Varipette.
A 99 % solution of n-amyl alcohol is a highly viscous solution. We recommend working with an instrument that operates according to the positive displacement principle like Multipette/Repeater, Varipette, or Biomaster.
It is best to use a positive displacement device like the Multipette/Repeater. Positive displacement devices are most suitable for precise and drip-free dispensing of liquids with high vapour pressure. As the liquid is enclosed in a tip with integrated piston, the solvent vapour does not come into direct contact with the instrument.
No, we cannot guarantee this. Of course we work carefully and cleanly in production, but no special measures are taken to prevent the infiltration of nucleic acids. To protect your pipette from contamination, we recommend using positive displacement pipettes, for example, our Biomaster or filtertips (ep Dualfilter T.I.P.S. or ep Dualfilter T.I.P.S. SealMax).
Following contamination of pipettes with radioactive liquids, we recommend placing the contaminated parts in a complex-forming liquid or special cleaning solution. Then rinse very thoroughly with distilled water and dry. Grease piston lightly afterwards.
Exactly in the same way as liquids at room temperature, however, please note that solutions may behave differently. In addition, the pipetting accuracy / precision may be outside the permissible error limits. In order to achieve maximum accuracy / precision, all components should have the same temperature: pipette, tips, liquid, and the surrounding air.
This belongs to the permissible errors of your specific application. In general an adjustment of air cushion pipettes, in other words altering the stroke of the pipette, is required for solutions of a density größer 1.2 mg/µL. <br />Please be aware that variable manual pipettes turn into "fixed-volume pipettes" when being adjusted: They can only be adjusted to a specific liquid to one volume and not across the entire dispensing range.<br />Eppendorf manual pipettes have a user adjustment for temporary adjustment purposes. This user adjustment can easily be set back to manufacturer settings without the need for recalibration. For the correct procedure and examples for settings of user adjustments for different liquids please see the operating instructions and CD enclosed to your pipette.
The measuring values of the analysis scales are multiplied by the correction factor Z (see SOP pipettes). This takes into account the density of the water at the relevant temperature and the relevant air.
ISO 8655 addresses the needs of suppliers, test houses, and users and specifies the general requirements for piston-operated liquid handling devices. It is structured in seven chapters:<br />ISO 8655-1: Terminology, general requirements, and user recommendations<br />ISO 8655-2: Piston pipettes<br />ISO 8655-3: Piston burettes<br />ISO 8655-4: Dilutors<br />ISO 8655-5: Dispensers<br />ISO 8655-6: Gravimetric method for the determination of measurement error<br />ISO 8655-7: Non-gravimetric methods for assessment of equipment performance (titration, photometry)
The systematic error describes the deviation of the dispensed volume from the nominal volume or from the selected volume of the piston stroke device, and is determined by establishing the mean value of (usually) 10 measurements. The random error describes the mean variation of the dispensed volumes from the mean value of the dispensed volumes, and is determined by calculating the repeat standard deviation of (usually) 10 measurements.
The Z factor is included in EN ISO 8655-6 and was incorporated into our SOP. As we understand it, it was incorporated in the standard by the Physikalisch Technische Bundesanstalt in Braunschweig.<br />The Z factor describes the density of water at a particular temperature using a 5th degree polynomial. Furthermore, the density of water is corrected by the density of air (derived from air pressure) and a fixed correction value for balances. These corrections are the key reasons for the deviation from density values in various books of tables.
According to the EN ISO 8655 standard, a variable pipette should be calibrated to 3 volumes during conformity testing:<br />1. Nominal volume,<br />2. 50 % of nominal volume,<br />3. Smallest value that can be set or 10 % of nominal volume.
The weight fluctuations you measured would appear to be a temperature problem. Please ensure that the pipette, the distilled water used for testing, the tips etc… are all at the same temperature. It is recommended that the pipettes be placed in the weighing room at least 2 hours before the test is performed. While measuring, ensure that transfer of heat from your hands is kept to a minimum (otherwise weight fluctuations may occur!) Tip: do not constantly grasp the pipette in the palm of your hand while waiting for each measurement result! We recommend our standard operating procedure (SOP) for pipettes as a source of basic information on pipette calibration.
According to ISO 8655, all channels of multi-channel pipettes are to be tested. All channels have to be filled but only the channel to be tested is measured. Because of the high number of measurements (8-channel pipette: 240 measurements, 12-channel pipette: 360 measurements), it makes sense to send the multi-channel pipette to a professional calibration lab. These labs have special constructions for balances to ensure that all channels are filled but only one channel is measured.
To attach the Multipette holder adapter you first need to remove one pipette holder from the pipette carousel. To do this, undo the screw at the top end of the pipette holder. Once the pipette holder has been removed from the carousel you can put the Multipette holder in the free space in the carousel and screw it all firmly together again.
Our pipettes are checked for a minimum lifetime of five years. This means a normal use with 200,000 strokes, 26,000 volume changes, 100,000 tip ejections, and 175 autoclavings without the pipetting results and pipette material being affected.
If the pipette grease is not removed actively (e.g., by cleaning with alcohols before autoclaving), there is no need to regrease the piston-cylinder system. During endurance testing (200,000 strokes, 26,000 volume changes, 100,000 tip ejections, and 175 autoclavings), the Reference 2 was not regreased and gravimetrically checked after each autoclaving. No decline in systematic and random measurement error was observed. If regreasing is needed, Eppendorf grease for Research plus and Reference 2 must be used. Only this grease withstands the heat in the required manner.
The Reference 2 is mounted in a way that all materials have room for expansion. Furthermore, only materials are used which are resistant to severe conditions, e.g. autoclaving (pressure, rise in temperature).
No, the Reference 2 does not fit into the mounts for Research plus / Research / Reference. A Reference 2 mount can be integrated in the Research plus / Research / Reference carousel or a Reference 2 carousel can be used. The reason for this switch was to ensure a better fit of the pipettes in the Reference 2 mounts.
Yes. The scope of delivery includes a locking ring with which the spring-loaded tip cone can easily be inactivated. Disassemble the upper from the lower part of the pipette and push the locking ring onto the lower part from the top. Please refer to the operating manual for an illustrated description.
Reference 2 pipettes offer factory adjustment and user adjustment. The factory adjustment should be changed if the pipette was found to be out of specifications during calibration. Before adjusting, exclude other causes such as pipette handling, environmental errors, or worn-out parts. The user adjustment is an easy way of adjusting the pipette temporarily to different conditions (e.g. pipetting a liquid with high density). Please note that the adjustment is only valid for the chosen volume and not for the full volume range.
The RFID chip is used to clearly identify an instrument. Identification data, e.g. serial number or results of quality control tests by the manufacturer, are stored on the RFID chip. This data cannot be changed or deleted.
The user decides upon the frequency of calibration, the number of test volumes and the number of measurements for each test volume within the framework of monitoring his test materials. This can vary depending on the frequency of use of the pipette, the number of users of the device, the aggressiveness of the liquids to be dispensed and the error limits deemed acceptable by the user. However, an inspection should be carried out at least once a year. See also EN ISO 8655-6.
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