Solid phase extraction abd sequential elution for pre-concentration of traces of Mn and Zn in analysis of honey by flame atomic absorption spectrometry

摘要

A pre-concentration procedure based on solid phase extraction and two-step elution was developed for the determination of the total concentrations of traces of food safety relevant elements (Mn and Zn) in ripened honeys. Accordingly, 10% (m/v) solutions of analyzed honeys (100 ml) were passed at 20 ml min~(-1) through resin beds of Dowex SOW x 8-400 to retain Mn and Zn ions and separate them from the glucose and fructose matrix. Afterwards, 20 ml of a 0.5 mol l~(-1) HNO3 solution was used to elute K and Na, easily ionized interfering metals. Finally, Mn and Zn were recovered prior to measurements by iame atomic absorption spectrometry (FAAS) using 5 ml of a 2 mol 1~(-1) HCl solution. This procedure was applied in the analysis of six honeys and resulted in the determination of 0.2-43.6 μg g~(-1) of Mn and 0.2-1.2 μg g~(-1) of Zn with the precision (n = 3) within 3-10% and an accuracy better than 5%. Detection limits of Mn and Zn with this pre-concentration/separation procedure and the FAAS detection were 4 and 3 ng g~(-1), respectively.