Trace Metal Contamination During Grinding of Plant Samples |
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Authors: | Luong Bui Bich Hanh Phung Thi My Rinh Pham Dinh Trang Pham Minh Thang Do Trong Stephen Harper |
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Institution: | 1. Department of Soil Genesis and Classification, Soils and Fertiliser Research Institute, Hà N?i, Vi?t Nam;2. School of Agriculture and Food Sciences, University of Queensland, St Lucia, Australia |
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Abstract: | Inductively coupled plasma-mass spectroscopic (ICP-MS) analysis of leaves from 22 cabbage crops in the Sa P? and B?c Hà districts of Láo Cai Province, North-Western Vi?t Nam, revealed unexpectedly high concentrations of chromium (Cr) and nickel (Ni). The concentrations were strongly linearly related (r2 = 0.94), indicating sample contamination during grinding through a stainless-steel hammer mill. We tested this hypothesis in two ways. First, brown rice ground through the same mill was contaminated not only by Cr and Ni, but also cobalt (Co), iron (Fe) and molybdenum (Mo). Second, scanning electron microscopy/energy dispersive analysis of x-rays (SEM/EDS) of the ground samples revealed small fragments with co-located Fe, Cr and Ni, consistent with stainless steel wear fragments. Other grinders may perform differently and we suggest that quality assurance protocols for trace metal analysis of plants should include testing for grinder wear metals. Lastly, brown rice appears to be convenient for investigating contamination of plant tissues during grinding. |
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Keywords: | Inductively coupled plasma-mass spectroscopy (ICP-MS) foliar analysis mineral nutrition iron (Fe) chromium (Cr) nickel (Ni) cobalt (Co) molybdenum (Mo) Si and wear |
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