The goal of this thesis was to develop different approaches for quantification in XRF analysis using a special spectrometer for low Z elements. The excitation occurs with a polychromatic X-ray spectrum and a polycapillary optic is used for focusing the beam, which modifies the primary beam in an energy-dependent way. Since the intensity distribution of the primary spectrum after the polycapillary is not known, in this thesis the focus lay on experimental approaches for quantification. For the first approach, area scans with overlapping measuring spots were performed over Sr and Zr residues of different masses that were produced from certified liquid standards. The relationship between the sum intensities of the whole measuring area and the applied mass of Sr and Zr was surprisingly linear. The intensities that were obtained in this manner should then be corrected for multiple counting due to the overlapping measuring spots. For this, the beam size for Zr and subsequently also other elements was determined. Especially the result for Zr differed from the theoretically expected values. It is likely that the lateral intensity distribution of the beam depends on a variety of factors, which make an overlap correction nearly impossible without further investigation. At this point, this first approach cannot be deemed suitable for quantification. For the second approach, certified reference materials were used. They consisted of animal bone powder and had been pressed into pellets for former measurements. Elements were not really distributed homogeniuously, so intensities were averaged over several measuring spots. By comparing the reference materials to each other, it was seen that they can only be used for semiquantitative analysis at this point, since the errors for the expected concentration values were rather high. In general, though, this approach is very promising and could work with a different choice of reference materials if they are more homogenious or if the number of measuring spots for calculating the average intensity is optimized. Also, it was seen that the spectrometers sensitivity for low Z elements is significantly influenced by covering the sample with Kapton foil as well as performing a detector conditioning before the measurement, which has an impact on the detectors efficiency for light elements in particular.