Closed-vessel miniaturised microwave-assisted EDTA extraction to determine trace metals in plant materials

摘要

The demonstration of an innovative miniaturised closed-vessel microwave-assisted extraction (μMAE) method under the use of EDTA (μMAE-EDTA) for determination of trace metal contents in grassland (Lolio-Cynosuretum) was examined by ICP-OES. The evaluation of the method was done by comparison of the results with another miniaturised closed-vessel microwave HNO_3 method (μMAE-H) and with a macro-scale microwave procedure (MAE-H). Concerning their homogeneity certified plant reference materials (CRMs) were used for validation of the applicability of uMAE-EDTA procedure. For CRMs and 72 real plant samples, no significant differences were found between μMAE-EDTA and MAE-H in the determination of Cd, Co, Cu, Mn, Ni, Pb, and Zn contents. Recovery rates achieved from μMAE-EDTA for CRMs ranged between 100.0-102.6% for the investigated elements. The key characteristics of μMAE-EDTA for determination of trace metal contents in plant samples are: (ⅰ) suitability as a high-throughput procedure; (ⅱ) consumption of minimum volume of extracting agent and minimum amount of sample; and (ⅲ) combination of fast, safe and environmentally friendly extraction procedure.