European Instruments service and calibrate pipettes to ISO and UKAS standards and supply a certificate of calibration to the customer showing the performance of the pipette. Limits can then be applied to these results to assess for suitability of use. But where do these limits come from?
Using Customer supplied limits
Many customers have limits they would like us to apply to the calibration results. When a customer does supply limits, European Instruments can input these limits into our calibration software and the software will assess if the customer’s limits are being met. When customer’s limits are to be used it is preferable that they are supplied to us in actual values for each test point being calibrated
Using European Instruments Standard limits
Many customers however do not have specific limits that they would like applied to the calibration results, but rely upon us as the service provider to let you know when a pipette is no longer performing. For this purpose we will apply our “EI Standard Pipette Limits” Our limits have been determined based upon our experience of pipettes in use, manufacturer specification and looking at relevant pipette standards such as ISO8655. These limits have been set to assess the performance of the pipette over its lifetime.
Key Points of EI Standard Limits
- They are based on our many years of experience and in line with standards such as ISO8655.
- They allow for effects such as age of the pipette and tip selection.
- They are realistic against manufacturer’s “out of box” specifications.
- They are the same for each pipette volume being calibrated regardless of make or model.
Table of EI Standard Limits
Inaccuracy:
| % | Possible Test Points within the range of the Pipette | ||||||||||||
| Nominal | 1 | 2 | 5 | 10 | 20 | 50 | 100 | 200 | 500 | 1000 | 2000 | 5000 | 10000 |
| 1 | 4 | – | – | – | – | – | – | – | – | – | – | – | – |
| 2 | 8 | 4 | – | – | – | – | – | – | – | – | – | – | – |
| 5 | 10 | 5 | 2.5 | – | – | – | – | – | – | – | – | – | – |
| 10 | 12 | 6 | 2.4 | 1.5 | – | – | – | – | – | – | – | – | – |
| 20 | – | 8 | 3.2 | 1.6 | 1 | – | – | – | – | – | – | – | – |
| 50 | – | – | 8 | 4 | 2 | 1 | – | – | – | – | – | – | – |
| 100 | – | – | – | 8 | 4 | 1.6 | 1 | – | – | – | – | – | – |
| 200 | – | – | – | – | 6.4 | 2.6 | 1.3 | 0.8 | – | – | – | – | – |
| 500 | – | – | – | – | – | 6.4 | 3.2 | 1.6 | 0.8 | – | – | – | – |
| 1000 | – | – | – | – | – | – | 6.4 | 3.2 | 1.3 | 0.8 | – | – | – |
| 2000 | – | – | – | – | – | – | – | 6.4 | 2.6 | 1.3 | 0.8 | – | – |
| 5000 | – | – | – | – | – | – | – | – | 6.4 | 3.2 | 1.6 | 0.8 | – |
| 10000 | – | – | – | – | – | – | – | – | – | 6.4 | 3.2 | 1.3 | 0.8 |
CV %:
| % | Possible Test Points within the range of the Pipette | ||||||||||||
| Nominal | 1 | 2 | 5 | 10 | 20 | 50 | 100 | 200 | 500 | 1000 | 2000 | 5000 | 10000 |
| 1 | 5 | – | – | – | – | – | – | – | – | – | – | – | – |
| 2 | 5 | 2.5 | – | – | – | – | – | – | – | – | – | – | – |
| 5 | 7.5 | 3.8 | 1.5 | – | – | – | – | – | – | – | – | – | – |
| 10 | 8 | 4 | 1.6 | 0.8 | – | – | – | – | – | – | – | – | – |
| 20 | – | 5 | 2 | 1 | 0.5 | – | – | – | – | – | – | – | – |
| 50 | – | – | 4 | 2 | 1 | 0.4 | – | – | – | – | – | – | – |
| 100 | – | – | – | 3 | 1.5 | 0.6 | 0.3 | – | – | – | – | – | – |
| 200 | – | – | – | – | 3 | 1.2 | 0.6 | 0.3 | – | – | – | – | – |
| 500 | – | – | – | – | – | 3 | 1.5 | 0.8 | 0.3 | – | – | – | – |
| 1000 | – | – | – | – | – | – | 3 | 1.5 | 0.6 | 0.3 | – | – | – |
| 2000 | – | – | – | – | – | – | – | 3 | 1.2 | 0.6 | 0.3 | – | – |
| 5000 | – | – | – | – | – | – | – | – | 3 | 1.5 | 0.8 | 0.3 | – |
| 10000 | – | – | – | – | – | – | – | – | – | 5 | 2.5 | 1 | 0.5 |
Notes:
(ii) Not all test points are available on all pipettes (see your pipettes useful operating range).
(iii) Pipettes with test points outside of the values shown in the chart will be based on 80% of the nominal value.
(iv) Single volume pipettes will use the nominal value only.
(v) Multichannel pipettes will use the values in the chart as an average over all channels tested.