EXTRAPOLATIVE VERSION OF THE INDIRECT CALIBRATION METHOD

In this work, an idea is theoretically and experimentally developed the adaptation of the indirect method to calibration in the extrapolative mode. The proposed approach enables estimation of the analytical results through an extrapolative method in the case of both positive and negative slopes of calibration dependence. The principle of the method has been presented and its analytical usefulness has been experimentally tested, giving special attention to examination of the possibility of overcoming interferences. The experimental examples encompass the determination of phosphate and chlorite by flame atomic absorption spectrometry (FAAS) and UV/VIS spectrophotometry, respectively, in the presence of different strong interferents. It has been proven that the method can be an effective calibration tool provided the specific instrumental and chemical conditions are fulfilled.