Mls 1200

The oven dried plant samples were ground and digested in 5:1 (v/v) HNO₃:HClO₄ (5 mL) in a microwave oven (MLS 1200, Milestone, FKV, Boldone, Italy). The Cd and Mo concentrations were measured in the digested samples by inductively coupled plasma (ICP)-optical emission spectroscopy (Vista-PRO, Varian, Inc., Palo Alto, California, CA, USA) and ICP-mass spectrometry (ICP-MS) (ELAN DRC-e, Perkin-Elmer Sciex, Wilmington, DE, USA) [27 (link),28 (link)].

The owl pellets were measured for length, breadth, and weight and dried in a hot-air oven over 24 h at 105 °C until no weight reduction occurred. Pellet remnants were ground using a homogenizer and were weighed using a weighing balance. Element residues (µg/g) in the pellets were assessed on a dry weight (DW) basis [6 (link)]. Five grams of the pellet was digested using a microwave digester (Milestone, MLS 1200) using 10 mL nitric acid (HNO₃; 69% GR) for 10 min, 1 mL perchloric acid (HClO4; 70% GR) for 5 min. and 5 mL hydrogen peroxide (H₂O₂ 30% GR) for 10 min at 250 W magnetron power using the acid digestion method [14 (link)]. The digested solutions were shifted using filter paper and were kept in a deep freezer until analysis. Metals such as chromium (Cr), manganese (Mn), cobalt (Co), molybdenum (Mo), selenium (Se), vanadium (V), copper (Cu), nickel (Ni), lead (Pb), zinc (Zn), and iron (Fe) were determined using ICP-MS (inductively coupled plasma mass spectrometry). After being run in triplicate, the quantification and the average were used for further analysis. The detection limits (μg/kg d.w.) were as follows: Cr 0.1, Mn 0.1, Co 0.1, Mo 0.1, Se 0.1, V 0.1, Cu 0.1, Ni 0.1, Pb 0.1, Zn 0.1, and Fe 0.1. The recoveries were adjusted between 95 and 101 % for all of the metals analysed.

The elemental composition of the three stainless steel powders used was measured after 10 mg portions were dissolved in a mixture of 2 mL of aqua regia and 0.5 mL of hydrofluoric acid with microwave-assisted heating (MLS 1200, Teflon container SV140, 10 bar, Milestone, 556 J. Sorisole, Italy). Before digestion, 10 µg of beryllium (as chloride) was added as internal standard before dilution to 15 mL with de-ionized water. The elemental composition was measured with a Perkin-Elmer Optima Model 7300 DV inductively coupled plasma optical emission spectrometer (Perkin-Elmer Inc., Waltham, MA, USA).
After removing the TEM grids from the air filter surface, the same analytical procedure was used for measurement of the elemental content of the particulate matter collected by the filters.