Pipetteringsmetod

Pipetteringsmetod, or pipetting technique, refers to the methods used to measure and transfer precise volumes of liquid with a pipette in laboratory work. It covers manual and automated approaches, such as air-displacement micropipettes and positive-displacement pipettes, and applies to single- and multi-channel systems used for tasks from sample preparation to assay setups.

Key considerations include accuracy, precision, calibration, and adherence to standard operating procedures. Pipettes are calibrated to deliver nominal volumes and require regular verification against reference standards to maintain reliability. Good technique reduces systematic and random errors and ensures reproducibility across experiments.

Common procedures and best practices involve several steps. Preparation includes selecting the correct tip size and pre-wetting tips by aspirating and dispensing a small volume. For aspiration, hold the pipette vertically, insert the tip just below the liquid surface, and operate the plunger smoothly to avoid bubbles, drawing up the intended volume with a short pause after aspiration. For dispensing, eject against the vessel wall and, if required by the protocol, perform a brief blow-out to deliver the final droplets. For viscous liquids or volatile solvents, reverse pipetting may improve accuracy. After dispense, eject the tip into a waste container to prevent contamination.

Common issues include bubbles, over- or under-aspiration, and volume changes due to temperature or liquid properties. These can be mitigated through regular calibration, temperature control, and careful adherence to technique.

Applications of pipetteringsmetod span molecular biology, biochemistry, clinical chemistry, and analytical assays. Training, documentation, and traceability are essential for maintaining measurement quality in laboratory practice.