ELIMINATION OF THE UNKNOWN IRRELEVANT MATRIX ABSORBENCY BY USING THE H-POINT STANDARD ADDITIONS METHOD (HPSAM)

It is demonstrated how the H-Point Standard Additions Method (HPSAM) u sing DELTAA as analytical signal (from data at three previously select ed wavelengths) is only related with analyte concentration when unknow n irrelevant matrix absorbance is present. The method is compared with the most common previously reported methods, such as derivative spect roscopy or the compensation method. The obtained results show that the proposed HPSAM leads to the same found concentration of analyte as th e other reported methods, except detection limits and standard deviati on for six replicates which are lower, because of the use of absorbanc e data (instead of first derivative data as usual). In addition, the o btained data permit us to differentiate between linear and non-linear spectral behaviour for the interferent. The method was also applied to routine analyses using single-standard calibration.