Pipetting is a basic function in the laboratory that requires careful handling of precise volumes of liquid. Error-free pipetting is very important for obtaining quality results. Air displacement and positive displacement pipettes are two types available. Air displacement units are generally used with aqueous solutions such as buffers, diluted acids or alkalis. This device is highly accurate for standard pipetting applications. Positive displacement types are used for highly viscous and volatile liquids such as protein, nucleic acid solutions or methanol.
Best pipetting practices for clinical laboratories include choosing quality pipetting instruments, optimizing liquid handling workflows calibration and routine operation as well as using the right technique. When choosing a pipette and its tip for your application, consider certain factors such as – physical properties of your sample, type of analysis you are performing and the volume range required. Make sure to choose an instrument that requires minimal hand and finger effort.
Errors in test results can also be due to factors such as a poor fit with the pipette and inconsistent tip dimensions. Remember that the pipette tips are designed for single use. They should not be cleaned for reuse. Choose a tip that is manufactured reliably. Based on the specific needs, you can choose from a standard tip, a wide bore tip, gel loading tips or purity certified tips. Leading suppliers of lab equipment offer quality tips from the established manufacturer VistaLab Technologies. Filter tips can keep your device clean and protect both the instrument and the sample from contamination. It prevents aerosols as well as any excess liquid or foreign particles from entering the pipette.
Other steps to ensure pipetting accuracy in laboratory settings include:
- Pre-wetting the tip to prevent cross-contamination
- Aspirating the device at 90 degrees and dispensing at 45 degrees
- Releasing plunger with a slow, controlled motion to avoid air bubbles
- Storing device in an upright position when not in use to prevent residual liquid from entering into the tip cone
Make sure to check the instrument daily for dirt and dust. Cleaning requirements depend on the device’s use and the liquid. Prior to cleaning, make sure to check the chemical compatibility. Depending on the microorganisms of concern, chemical disinfectants or sterilants can be used to decontaminate surfaces and equipment if autoclaving is not possible.