Douglas Cardoso Dragunski

Phytoaccumulation and effect of lead on yield and chemical composition of Mentha crispa essential oil

AbstractHeavy metals such as lead (Pb) accumulated in soil may become a problem for plant growth and human health. An alternative is to grow nonfood crops in these contaminated areas. A pot experiment was carried out in order to investigate the effect of increasing doses (900, 1,800, 3,600, 7,200, and 9,000 mg kg−1) of Pb on the yield and chemical composition of essential oil and phytoaccumulation of garden mint (Mentha crispa L., Lamiaceae). It was observed that the length of the root and aerial parts of this species was not significantly affected in different assayed experiments when compared to the control. However, the leaf number, budding, and green mass were very influenced by the presence of Pb in the soil, showing a significant resistance. Regarding Pb phytoaccumulation, it was verified an accumulation of this metal in roots and aerial parts. Although M. crispa is a species that tolerates high concentrations of Pb, it is not considered a Pb hyperaccumulator species. Considering the production of e...

Application of Ni(II)-imprinted cross-linked poly(methacrylic acid) synthesised through double-imprinting method for the on-line preconcentration of Ni(II) ions in aqueous media

The present paper describes the feasibility of on-line preconcentration of nickel ions from aqueous medium on Ni(II)-imprinted cross-linked poly(methacrylic acid) (IIP) synthesised through a double-imprinting method and their subsequent determination by FAAS. The proposed method consisted in loading the sample (20.0 mL, pH 7.25) through a mini-column packed with 50 mg of the IIP for 2 min. The elution step was performed with 1.0 mol L−1 HNO3 at a flow rate of 7.0 mL min−1. The following parameters were obtained: quantification limit (QL) – 3.74 µg L−1, preconcentration factor (PF) – 36, consumption index (CI) – 0.55 mL, concentration efficiency (CE) – 18 min−1, and sample throughput – 25 h−1. The precision of the procedure assessed in terms of repeatability for ten determinations was 5.6% and 2.5% for respective concentrations of 5.0 and 110.0 µg L−1. Moreover, the analytical curve was obtained in the range of 5.0–180.0 µg L−1 (r = 0.9973), and a 1.64-fold increase in the method sensitivity was observed when compared with the analytical curve constructed for the NIP (non-imprinted polymer), thus suggesting a synergistic effect of the Ni(II) ions and CTAB on the adsorption properties of the IIP. The practical application of the adsorbent was evaluated from an analysis of tap, mineral, lake and river water. Considering the results of addition and recovery experiments (90.2–100 %), the efficiency of this adsorbent can be ensured for the interference-free preconcentration of the Ni(II) ions.