Endy:Victor3 plate reader\Measurement variation
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Also see: Victor3 plate reader
I measured the variation in repeated measurements on the plate reader.
Fluorescence
I measured the fluorescence of a well containing E. coli expressing YFP and a well containing untransformed MG1655. Ten measurements were taken over a 5min period.
Reading | MG1655.YFP | MG1655 |
1 | 108445 | 8142 |
2 | 109492 | 8320 |
3 | 110628 | 8194 |
4 | 109728 | 8188 |
5 | 109334 | 8304 |
6 | 109988 | 8329 |
7 | 110382 | 8480 |
8 | 109248 | 8205 |
9 | 107576 | 8238 |
10 | 107560 | 8228 |
Mean | 109238 | 8263 |
Stdev | 1016.07 | 93.1 |
CV | 0.0093 | 0.011 |
Absorbance
I measured the absorbance of the same wells. Measurements were taken over the same 5min period.
Reading | MG1655.YFP | MG1655 |
1 | 0.476 | 0.650 |
2 | 0.471 | 0.651 |
3 | 0.469 | 0.648 |
4 | 0.463 | 0.644 |
5 | 0.462 | 0.643 |
6 | 0.465 | 0.643 |
7 | 0.460 | 0.641 |
8 | 0.457 | 0.639 |
9 | 0.458 | 0.639 |
10 | 0.456 | 0.639 |
Mean | 0.46 | 0.64 |
Stdev | 0.00623 | 0.0042 |
CV | 0.013 | 0.0065 |
Notes
The absorbance readings for both wells appear to decrease over time. Over a 5 min time course this is unlikely to be due to evaporation. It may be due to settling of the cells in the well. The same effect was not observed for the fluorescence readings.