Introduction
Handling pipetting volumes below 1 µl with a precision better than 10 % is currently one of the major needs in the present automated drug discovery. CyBio has complete an initial round of testing demonstrating that the CyBi™-Well vario and CyBi™-Well 2000 with 384 tips are capable of pipetting 0.2 µl into a wet plate with less than 5% CVs. The following data are results of precision and accuracy tests with a CyBi™-Well vario and a CyBi™-Well 2000 with 384 pistons according to the procedure described below.
Application purpose
PrecisionFigure 1 and 2 show the photometric determined values of the precision and the deviation of the single wells.
Accuracy
Figure 3 shows the accuracy values for the range of 0.2 µl to 3 µl.
The accuracy of the
CyBi™-Well 2000 with 384 channels was determined by weighing the microplates after pipetting.
The results are affected by some methodological parameters as described in Table 1.
Why you should choose this solution
The results shown in Fig. 1 and 2 prove that the CyBi™-Well 2000 and the CyBi™-Well vario in the 384 tip format are able to achieve CV values less than 5 % for 200 nl pipetting volume and less than 2 % for 1 µl pipetting volume when pipetting into a liquid in the 384 plate format.
The values shown in Figure 1 and 2 were obtained by the following procedure.
- The measurement was taken in Greiner 384-well clear bottom microplates with 25 µl CyBi™-Tips.
- The concentration of the tested solution were adjusted so that the resulting extinction at 405 nm was between 0.4 and 1.2. The concentration was 417 mg p-Nitrophenol per liter for 0.2 µl and 0.5 µl and 139 mg p-Nitrophenol per liter for 1.0 µl, 2.0 µl and 3.0 µl in 0.1 N NaOH.
- 50 µl 0.1 N NaOH per well were placed in the above mentioned microplate with a CyBi™-Well 2000.
- Only new tips were used for the precision measurements and they were rinsed with the p-Nitrophenol solution having the following settings:
Piston Speed: 100 rpm
No. of rinse cycles: 10
Rinse volume: 10µl
- Measurement took place by pipetting the test volume into the 384 microplate with the already placed NaOH-solution. During dispensing the test volume the pipetting tips were immersed about 1 mm into the NaOH-solution. The remaining volume was dispensed back into the reservoir, supply vessel, resp.
- Testing took place in the manual mode with an aspiration volume of 10 µl. A first pipetting cycle run back into the reservoir, supply vessel, resp.
- A single channel vertical photometer with the option for 384 microplates -Tecan Spectra Flour Plus - was used. Previous to the measurement, the geometric parameter of the well grid has been defined. Measurement of extinction in the vertical photometer.
- Due to the less favorable miscibility of the p-Nitrophenol-solution with the NaOH-solution in 384 microplates, the following process were executed before the measurement: The substances were mixed in an orbital shaker for 15 minutes.
Mixing in the orbital shaker for 10 minutes at 1000 rpm
Waiting 30 - 45 minutes
Repeat mixing for 10 minutes at 1000 rpm
- The microplate were sealed after the addition of the NaOH-solution, after pipetting and during the mixing process.
