Nowadays dietary supplements are widespread on the market. As they are used by many people, I decided to investigate their phase composition and compare my findings with the product's declaration. I preformed X-ray powder diffraction, which involves irradiating the samples with X-rays of a specific wavelength. The analysed sample must contain crystalline matter, as the method relies on the periodic arrangement of atoms in crystals. I analysed 21 samples of dietary supplements.
To determine the phase composition, I used two software packages, X΄ pert HighScore Plus and Crystallographica Search-Match (CSM). I used X΄ pert HighScore Plus to display the recorded diffractograms and compare them based on common traits of the sample. I sorted the samples into 6 groups: based on magnesium, calcium, iron, zinc and selenium content, and samples in the form of an effervescent tablet. The CMS software package allowed me to compare the difractogram of a standard solution with the diffractogram of the sample.
Using qualitative analysis, I was able to confirm that the phase composition of most samples matches the information in the product’s declaration. I wasn't able to identify magnesium citrate, as it wasn't present in the PDF collection. I also wasn't able to identify selenium in the samples, as its quantity was too low to detect. The typical diffractogram of an amorphous substance can also be found amongst the recorded diffractograms.