Icap 6300 duo

In total, 10 mg of the complex powder was placed in 20 mL of a 0.2 molar solution of HNO₃ to prepare extracts of the complexes. Na and Cu concentrations were identified in the complex extract using simultaneous inductively coupled plasma optical emission spectrometer (ICP-OES) model iCAP 6300 DUO by Thermo Fisher Scientific Company (168 Third Avenue, Waltham, MA 02451, USA) equipped with a CID detector. Together, the radial and axial view configurations enable optimal peak height measurements with suppressed spectral noises [49 (link)]. The concentration of Na and Cu ions was determined, respectively, by the spectral lines 588.995 and 324.754 nm. We used Sc as internal standard (10 ppm in the sample), and all the standards were by the Perkin Elmer corporation.

The eutectic mixtures (mol.%) 40NaF-60KF and 46.5LiF-11.5NaF-42KF were prepared with the following chemicals: lithium fluoride LiF (mass fraction of LiF 99.0%) (CJSC VECTON), sodium fluoride NaF (mass fraction of LiF 99.0%) (LLC “GRANCHIM”), potassium fluoride acidic KF‧HF (mass fraction of KF‧HF 99-101%) (LLC “GRANCHIM”).
The mixtures were prepared by direct fusion of the components in a glassy carbon crucible. KF·HF was used instead of hygroscopic KF. KF·HF decomposes at 673–773 K; the released HF prevents the hydrolysis of salts and simultaneously fluorinates oxygen-containing impurities. The mixture was kept at 923 K for at least 2 h. After cooling, the sample was transferred to a glovebox with an inert argon atmosphere. The preparation technique is described in detail elsewhere [25 (link)]. The contents of LiF, NaF and KF in the prepared sample were confirmed by the elemental chemical analysis (Li, Na, K) carried out using ICP-OES (iCAP 6300 Duo, Thermo Scientific, Waltham, MA, USA).
The neodymium trifluoride (NdF₃) was prepared by hydrofluorination of Nd₂O₃ according to technique described in [25 (link)]. The XRD confirmed the presence of a single hexagonal phase of NdF₃. Analysis of the oxygen content using the oxygen analyzer LECO OH836 indicated that its content in the prepared NdF₃ does not exceed 0.04 wt%.

For the nutritional analyses, seeds were sown in MJ media with or without the inoculation of the respective strain in combination with a particular nutritional treatment. Plates were placed horizontally, and the same growth conditions described above were used. At 21 DAS, 210 plants per treatment were collected, pooled, and dried for 48 h at 60°C. The metal content was analyzed in the dried tissues by HNO₃/HCl block digestion and analysis by inductively coupled plasma optical emission spectrometry (ICP-OES) using the instrument Thermo Scientific iCAP 6,300 Duo (Wheal et al., 2011 (link)). Nitrogen was analyzed by the Dumas combustion method using the Leco CN628 instrument.

Ag content in seedlings was quantified on day 7, at the end of the experiment, following the method described by Geisler-Lee et al. (2013) (link) with modifications. Seedlings of the three species were washed with DI water and their fresh weight (F.W.) was measured. Seedlings were fully digested using a mixture of 2 mL of HNO₃ used for trace-metal analysis (70%, Sigma–Aldrich, St. Louis, MO, USA) and 1 mL Co standard solution (1,000 mg mL⁻¹ in nitric acid, Sigma–Aldrich, St. Louis, MO, USA) heated at 120 °C for 30 min. After the solution cooled down, 2 mL of H₂O₂ used for trace analysis (H₂O₂, ∼30% w/w, Sigma–Aldrich, St. Louis, MO, USA) was added and the mixture was heated at 120 °C for 30 min. The digested samples were diluted with DI water to 20 mL and filtered using a 0.22-μm polyvinylidene fluoride (PVDF) syringe filter. Each diluted sample was analyzed using an inductively coupled plasma-optical emission spectrometer (ICP-OES, iCAP6300 Duo; Thermo Scientific, Waltham, MA, USA).

Approximately 5 mL of the paint samples were spread on glass slides using a different brush for each sample to avoid cross contamination. The glass slides were placed in an oven at 120°C for 2 hours. About 1.0 g each of the dried paint film was weighed into closed Teflon vessels and digested in a closed microwave digestion system using 10 mL of 70% nitric acid and 3 mL of 98% sulphuric acid. Samples were analyzed according to the standard procedures for digestion of very difficult samples.45 Digestates were then filtered and analyzed using inductively coupled plasma-optical emission spectrometry (Thermo Scientific iCAP 6300 Duo).
Sample blanks were also prepared alongside the samples. Dilutions were performed when necessary for the samples. Working standard solutions of 1–1000 μg/g were prepared from a multielement standard. A recovery study was carried out and recoveries of 80% for Pb and 110% for Cd were obtained.