Development of reference materials for the determination of calcium, iron, selenium, and zinc in dietary supplements

Food supplements are increasingly popular among consumers because of their convenience and nutritional value. Among the ingredients, essential minerals are added a lot because of their effects on health at all ages especially calcium (Ca), iron (Fe), selenium (Se), and zinc (Zn). To ensure the quality of products meets the requirements of consumers, the strengthening of control methods through testing is necessary. To ensure the quality of testing results, reference material/certified reference material is an effective tool for each laboratory. Nowadays, the source of reference material/certified reference material is highly dependent on overseas suppliers with expensive costs and inconvenient supply. This research was carried out in order to successfully produce a certified reference material of Ca, Zn, Fe and Se dietary supplements that can be supplied to domestic laboratories. Research results have produced certified reference material with characteristic values for Ca, Zn, Fe and Se content as follows: 786 ± 19.8 (mg/100g); 6.35 ± 0.40 (mg/100g); 7.42 ± 0.30 (mg/100g); and 18.4 ± 1.10 (µg/100g), respectively. The estimation of product shelf life is up to 1197 days.