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Key points the analyst must know

The analyst should know the following:

• the different types of pipettes available, e.g. volumetric, graduated, automatic and micro-pipettes, and their relative merits;
• which combination of pipette(s) to select to dispense a volume as accurately as possible, e.g. a volume of 12.0 mL;
• the different classes (grades) of glass pipette available, e.g. class A, B etc.;
• which pipette is suitable for dispensing aqueous samples, viscous samples, organic liquids, corrosive materials, radioactive samples and biological compounds;
• the difference between air displacement and positive displacement automatic pipettes;
• that certain graduated glass pipettes are calibrated for blow out delivery (and these are usually labelled on the side of the pipette itself);
• the uncertainty in the volume dispensed arising from the pipette and its use.