Effects of different drying processes on the concentrations 4 of metals and metalloids in plant materials 5 Hossain

9 Abstract The drying process of fresh plant materials may 10 affect the porous structure, dehydration and a number of 11 quality characteristics of these materials. Therefore, this 12 study has investigated the effect of different drying pro13 cesses on the variation of metal and metalloid concentra14 tions in the dried plant materials. Seven varieties of native 15 plant species collected from São Domingos mine were 16 analyzed by instrumental neutron activation analysis 17 (INAA) to investigate the effects of freeze-drying (FD), 18 ambient air-drying (AAD) and oven-drying (OD) process 19 on the concentrations of metals and metalloids in the plant 20 biomass. Comparison of ambient air-dried, oven-dried 21 and freeze-dried preparations allows a phenomenological 22 description of the dehydration artefacts. In the quantitative 23 analysis of metals and metalloids, FD and OD plant sam24 ples show the higher concentrations of metals and metal25 loids when compared to those in the AAD plant biomass. 26 The freeze-drying process is comparatively reliable for 27 determination of metals and metalloids concentrations in 28 plant materials. 29 30