Faldt [5] established a matrix equation to estimate the molecular composition of
the food powder surfaces. Each molecular component (e.g. carbohydrate, protein and
fat) in the powder is characterized by the specific ratio between the elements. Assuming
that the elemental composition of the surface is a linear combination of the elemental
compositions of the different molecular components in the sample, the data on the
elemental composition of the surface can be used to estimate the molecular composition
of the surface layer by solving a matrix equation: