Analysis of Essential and Toxic Elements in Jujube Fruits Collected from Different Locations in China

Purpose: To develop a simple and precise method for the determination of the levels of both essential and toxic elements in jujube collected from different locations in China.
Methods: Dried jujube fruits collected were digested by optimized microwave procedure. Inductively coupled plasma atomic emission spectrometry was employed to evaluate essential elements, viz, calcium, magnesium, manganese, iron and copper (Ca, Mg, Mn, Fe and Cu) and toxic elements, namely, aluminum, lead and cadmium (Al, Pb and Cd) in four jujube fruits.
Results: The results show that the jujube fruits were rich in essential elements and had low contents of toxic elements. The levels of the elements varied significantly amongst the four jujube fruits (p < 0.05). Method validation indicates that the proposed method was accurate and precision. The detection limits were 0.0005 - 0.0100 μg/mL while recovery ranged from 91.6 - 105.0%, with relative standard deviation (RSD) < 5%.
Conclusion: Five essential elements and two toxic elements (except cadmium) varied widely in their contents in the four jujube fruits. Knowledge of the contents of these elements would provide consumers with information on the quality of jujube fruits.

Keywords
Jujube fruits; Essential and toxic elements; Microware digestion; Inductively coupled plasma atomic emission spectrometry