XRD results shows anatase (101) and rutile (110) peaks along with some Ti peaks, based on anatase and rutile peaks volume fractions of anatase and rutile are determined, giving to total of 100%.
But if some amount of amorphous phase is also present along with crystalline, then how can we calculate % of each individual phases amorphous and crystalline both?
You need to add a precisely weighed quantity of internal standard, such as zincite or corundum. Then use quantitative Rietveld analysis to calculate the amorphous component. Much has been written about this approach and the exact route will depend on your particular software, and not knowing that I will not go into any more detail here. Please follow the references below to get you started
https://www.cambridge.org/core/journals/powder-diffraction/article/rietveld-quantification-of-amorphous-portions-with-an-internal-standardmathematical-consequences-of-the-experimental-approach/2FE16052DB0F37635CC16B007012208E
http://profex.doebelin.org/?page_id=515
http://www.esc.cam.ac.uk/resources/facilities/equipment-and-instruments/XRD/goethite_quantitative_analysis_2012.pdf
http://atarazanas.sci.uma.es/docs/tesisuma/16667426.pdf
