1. Metrological evaluation

The most widely used control method is the gravimetric method. However, there is another method, the colorimetric method:

• calibration using the gravimetric method consists in determining the volume of water delivered by the automatic pipette. This volume of water is obtained from knowledge of the measured mass and its density, after integration of corrections due to the influence of environmental parameters and any evaporation;

• Calibration using the colorimetric method involves introducing the element to be measured into a reaction resulting in a colored compound. Light absorption is determined for a specific wavelength, using a device that measures the intensity of transmitted light. To carry out the assay, simply refer to a calibration curve previously established from a series of solutions of known concentrations....