The publication is devoted to checking and calibration of fixed and variable volume piston pipettes. Both procedures that constitute the subject of the article are carried out using the gravimetric method.

In his publication, Slawomir Janas, PhD, describes the mechanism of the piston pipette, explains the differences between fixed and variable volume pipettes, and defines the gravimetric method.

The gravimetric method is used to record the mass of expelled liquid, which requires converting the weighing results into volume. For this purpose, one of two methods must be chosen. The first manner is based on a general formula to calculate the volume of the liquid, taking into account such factors as the effect of evaporation of the liquid in the cycle, the density of atmospheric air, the density of the mass standard, the density of water, the coefficient of thermal expansion of the pipette, and the temperature of the test.   

The second manner is simpler, as all these factors are taken into account in the so-called Z-correction factor. The conversion of liquid mass to volume involves using the appropriate value of the index at which the test is conducted (this value already takes into account the density of water, atmospheric pressure and temperature).

All the formulas and values mentioned here are included in the publication by Slawomir Janas, PhD, titled ‘Checking and Calibration of Fixed and Variable Volume Piston Pipettes Using a Gravimetric Method.’

The topics raised in the publication concern such RADWAG products as:

• AP-12.1.5Y Automatic Device for Multichannel Pipette Calibration
• MYA 21.5Y.P Microbalance
• XA 6/21.5Y.M.A.P Microbalance
• XA 82/220.5Y.A Analytical Balance
• XA 82/220.5Y Analytical Balance
• SDKP Workstation for Pipettes Calibration
• 0.5 μl ÷ 10 μl - RW8-101-20-9 Automatic Pipettes

We encourage you to read it.