DERIVATIVE UV-VIS SPECTROPHOTOMETRY IN ANALYTICAL-CHEMISTRY

The paper deals with theoretical and instrumental aspects connected wi th derivative spectrophotometry. Ideal absorption spectra and their de rivatives from 1st to 6th order are consequently discussed. The influe nce of intensity and width of peaks and relative position of the bands of the analyzed substances on the quality of the derivative spectra o btained has been discussed (choice of derivative order and measurement technique). Next, the dependence of the apparatus para meters on the course of derivative curves is described. Methods of obtaining derivat ives with particular consideration of the Savitzky-Golay numeric diffe rentiation technique are presented. The dependence of the number of sp ectrum points and degree of polynomial fit on the smoothness and diffe rentiation of spectra is described. Possibilities of improving the sel ectivity and sensitivity of determination using derivative spectrophot ometry are presented. Examples of applying this technique for the dete rmination of inorganic and organic analytes are shown.