Very thin samples show proportionality between the intensity and the weight per unit area of the analyte. Matrix effects do not exist. The matrix effects of very thick samples suitably can be corrected by multiple regression according to Eq. (1). Between these two kinds of samples the intermediate ones are situated with the intensity of the analyte as a function of the weight per unit area of the sample as an additional parameter of correction.
It was shown that these samples can also be corrected by multiple regression without knowing the weight per unit area of the samples by using the weight per unit area of the analyte instead of its concentration according to Eq. (5). This was demonstrated by calculation with simulated standards.
In addition to the described effects the correction program Eq. (5) is able to correct for the influences of dust particle sizes and their depth distribution in the filter.