# BISC209/S12: Calibration of Micropipets

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## Protocol for Micropipet Calibration

1. To calibrate your P1000, P 200, and P 20 micropipets, label 6 microfuge tubes (1-6) and weigh them on a top loading balance. Don't forget to tare the balance. Record the weights in a table in your lab notebook, like the one below.

2. Using the information in the table below, pipet the specified volumes into the pre-weighed microfuge tubes prepared in step 1 and then reweigh the tubes. Record all weights.

3. Calculate the weight of the water in grams by substracting the dry weight from the weight of the tubes with water. Note that 1000 microliters of water should weigh exactly 1 gram at room temperature.

4. If the water in any tube weighs more or less than 1 gram, repeat that tube. Ask your instructor to check your pipetting technique if your calibration continues to be off after several repeated attempts.

Tube # | Pre-weight | Tube Vol. in µl using P20 | Vol. in µl using P200 | Vol. in µl using P1000 | Weight of water grams |
---|---|---|---|---|---|

1 | _____ | 10 | 0 | 990 | ____ |

2 | _____ | 0 | 100 | 900 | ____ |

3 | _____ | 20 | 175 | 805 | _____ |

4 | _____ | 2 | 88 | 910 | ______ |

5 | _____ | 0 | 200 x 5 | 0 | _____ |

6 | _____ | 20 x 5 | 0 | 900 | _____ |