The validation procedure based on ISO 17025 standard has been used to study and illustrate
both the long-term stability of the calibration process of the DC-ARC solid sample
spectrometric method and the main validation criteria of the method. In the calculation
of the validation characteristics depending on the linearity(calibration), also the
fulfilment of predetermining criteria such as normality and homoscedasticity was checked.
In order to decide whether there are any trends in the time-variation of the analytical
signal or not, also the Neumann test of trend was applied and evaluated. Finally,
a comparison with similar validation data of the ETV-ICP-OES method was carried out.