Revisiting herbage sample collection and preparation procedures to minimise risks of trace element contamination

Abstract

35A renewed interest in trace elements (TE), as micronutrients as well as potentially toxic 36 elements, and new options for multi-element analysis has led to an increased number of 37 scientists engaging in TE studies. Accreditation, certification and quality control of TE

Red clover increases micronutrient concentrations in forage mixtures

“…Amongst the grass species timothy had the lowest micronutrient concentrations. This is similar to the species rankings published by Lindström et al (2012) and to conclusions regarding differences between forbs, legumes and grasses in previous studies (e.g. Pirhofer-Walzl et al, 2011).…”

“…Micronutrient analyses were made on each of the sown species from the first two harvests. To this end, these samples were milled (particle size <1 mm) in a cutting mill (Grindomix GM 200, Retsch GmbH, Haan, Germany) with a titanium knife and a plastic container which ensured minimal Table 2 Monthly total precipitation and mean air temperature during the experimental period 2010-2011 and the 30 years mean micronutrient contamination of the samples (Dahlin et al, 2012). The milled samples were wet digested with 7 M ultrapure nitric acid and concentrated hydrogen fluoride at increasing temperature until boiling, then filtered and analysed for Co, Cu, Fe, Mn, Mo and Zn by ICP-SFMS at ALS Scandinavia AB in Luleå, Sweden.…”

Prospecting for hyperaccumulators of trace elements: a review

“…Sampling after long periods of heavy rains, drought or high winds is not recommended because it brings about a risk of heavy contamination of plant samples with different soil and mineral particles leading to enrichment of plant samples with Al, Co, Cr, Cu, Fe, Ti, Sc and Zn (Dahlin et al, 2012).…”

“…Dahlin et al (2012) compared the influence of the use of several mills (hammer, ball, knife mills, knife and scissors) consisting of different materials (stainless steel, titanium, plastic, polystyrene resin and plexi-glass) on trace element contents in plant samples. A titanium-cutting mill contributed to the lowest Lou et al (2009) Pot cultures Easy to control and monitor Artificial conditions may not reflect a natural hyperaccumulation contamination whereas steel hammer and ball mills caused substantial contamination with Ni, Zn, Cr and Pb.…”

“…Cleaning of hyperaccumulator samples is difficult for plant samples obtained from herbaria. In this case, determinations of Al, Fe, Sc and Ti can be carried out to assess a scale of sample contamination with soil particles (Dahlin et al, 2012). Reeves (2003) cleaned samples from herbaria by agitation in deionized water for 120 s.…”