  In chemical analysis made by laboratories one has the problem of determining
the concentration of a chemical element in a sample. In order to tackle this
problem the guide EURACHEM/CITAC recommends the application of the linear
calibration model, so implicitly assume that there is no measurement error in
the independent variable $X$. In this work, it is proposed a new calibration
model assuming that the independent variable is controlled. This assumption is
appropriate in chemical analysis where the process tempting to attain the fixed
known value $X$ generates an error and the resulting value is $x$, which is not
an observable. However, observations on its surrogate $X$ are available. A
simulation study is carried out in order to verify some properties of the
estimators derived for the new model and it is also considered the usual
calibration model to compare it with the new approach. Three applications are
considered to verify the performance of the new approach.
