Guide to Error-free Pipetting

Overview

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  • Source: ABDOS Life Sciences

  • Date: 08 Sep,2021

Understanding the various nuances of improper pipetting is one of the most critical elements to ensure accuracy and precision, particularly in the face of high personnel turnover, growing laboratory workloads and increasingly complex tests. Thorough training regimens should be documented and include regular proficiency assessments, even if this is not a regulatory requirement. Continually employing consistent pipetting technique across the entire laboratory workforce ensures consistency of test results.

In practiced hands, a properly calibrated pipette is an accurate and precise instrument. As with any precision instrument, however, improper technique can negatively affect test results.

1. Pre-wet the pipette tip 3 times before the liquid handling step
Pre-wetting increases the humidity within the tip reducing evaporation of the samples being transferred.

2. Stay 2-6 mm below the meniscus while aspirating
While pre-wetting, make sure not to dip the pipette tip too far in to the solution to avoid droplets sticking to the outer surface of the tip.

3.Work at Temperature equilibrium between the pipette, solution and the air
Pipettes are susceptible to variation in the temperature of the samples dispensed. Cold liquids tend to deliver in excess, while warm liquids may deliver smaller volumes than expected. Unless otherwise specified, allow sufficient time for the temperature of your pipettes and liquids to equilibrate before use.

4. Use a Pipette stand in between pipetting steps
Minimize handling of the pipette and tips to avoid body temperature transfer to the pipette. Temperature transfer makes the air inside the pipette and tip to expand and thereby causes variation in sample volume being aspirated. So it is advisable to use a pipette stand in between pipetting steps.

5. Examine the tip before dispensing sample
Examining the tip for droplets on the outer surface can avoid pipetting volume errors. If droplets are found, wipe it carefully avoiding the tip orifice with a lint-free cloth.
6.Understanding the use of Standard and Reverse mode pipetting
Using Standard mode pipetting for aqueous solutions and reverse mode pipetting for viscous solutions avoids pipetting error by virtue of the nature of the sample.

7. Pause consistently after aspiration
Pausing consistently after aspiration while the tip is still inside the solution, allows the liquid inside the tip to stabilize.

8. Pull the pipette straight out
Make sure to avoid tip contact with the surface of the container after aspiration and pull it out straight.Surface tension is particularly important factor to avoid while pipetting small volumes which may otherwise may result in inconsistent sample volumes.

9.Use the correct pipette tip
Mismatch between a pipette and tip may result inappropriate seal between pipette and the tip to minimize sample loss. Exerting too much pressure may result damaging the tip altered sample volume.

10.Use consistent plunger speed and pressure

Depress and release plunger slowly and steadily for consistency in volumes being dispensed.Slow and careful handling of the plunger can avoid errors due to the air column displacing the liquid while pipetting.

ABDOS Pipettes:
ABDOS pipette meets the highest needs in precision and accuracy – combined with ultimate ergonomics and increased flexibility with sophisticated blend of features and functionality. It is easy to calibrate and maintain with tools supplied. It is supplied with operator manual that provides complete information on recalibration and maintenance of the pipette.

ABDOS Pipette Tips:
All ABDOS Tips are manufactured from ultrapure USP Class VI certified virgin polypropylene to ensure the highest quality & confirming to US FDA 21 CFR. Free from heavy metals, natural rubber & inhibitory plasticizers. Free from Bacteriostatic & Fungistatic property. Superior non- leeching performance in its class assures contamination free results. DNase, RNase & Pyrogen free. Precise Graduation mark for error free pipetting. Tips with High clarity for better visibility of samples. Diamond polished moulds for an extremely hydrophobic & smooth surface to ensure lowest retention in its class.


Please download the ABDOS Life Science Catalogue to comprehend the range of Liquid handling products being manufactured and marketed by ABDOS group.

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About Author

E.BIJOY VARMA, SENIOR MANAGER-MARKETING & STRATEGY