Optima 7300

Plaque-bearing ApoE⁻/⁻ mice (male, fed with high-fat diet for 12 weeks, n = 3) were intravenously injected with 150 μL of CuS-TRPV1 PBS solution (10 mg kg⁻¹). At 2, 4, 24, and 72 h postinjection, aortic arch and major organs were harvested immediately and weighed. Then these tissues were placed into borosilicate tube and digested in 70% w/v nitric acid containing 10 ppm Yttrium at 80 °C for 4 h. After cooled to room temperature, condensates were collected by centrifugation, and diluted to 5 mL with water. Samples were then filtered through a 0.45 μm hydrophilic PVDF membrane into 15 mL Falcon tubes. Standards were prepared by diluting 1000 p.p.m. cooper standards solution to 100 p.p.m., 10 p.p.m., 1 p.p.m., 0.2 p.p.m., 0.04 p.p.m. with 15% w/v nitric acid. ICP-AES was performed on the samples using the Optima 7300 (Perkin Elmer).

ICP-OES (PerkinElmer OPTIMA 7300) was used to calculate the concentration of silver nanoparticles in solution. 20 μL of the sample was digested with 200 μL of conc. nitric acid and the final volume made to 10 mL using ultrapure water before analysis.

The formulations of the experimental diets are shown in Table 1, together with the analyzed gross energy (GE), crude protein (CP), crude fat, calcium (Ca), and phosphorus (P) of the mixed diets after grinding. The gross energy was assessed using a Parr 1280 adibatic bomb calorimeter (Parr Instrument Co, Moline, IL) at The University of Sydney, Poultry Research Laboratory, Camden, Australia. The CP content was determined by Dumas method using a Leco FP-528 (Leco Corporation, St. Joseph, MI.) (Sweeney, 1989 ) and the crude fat by modified Randall system, where the petroleum ether was evaporated at 105°C instead of 102°C using Velp Scientifica, SER 148 solvent extraction unit (Usmate Velate, Monza and Brianza, Lombarda, Italy) (AOAC Official Method of Analysis, Method 2003.05 Method 2006, 2022 ) at Birling Avian Laboratories, Bringelly, Australia. The Ca and P content of the diets was determined at the University of New South Wales by inductively coupled plasma optical emission spectrometry (ICP) using a PerkinElmer OPTIMA 7300 (PerkinElmer Inc., Waltham, MA) following digestion with nitric acid and hydrogen peroxide as described by Hopcroft et al. (2020) (link).

For quality control total element concentrations were additionally measured with an ICP-OES “Optima 7300” (Perkin Elmer) in parallel to ICP-DRC-MS. Sample introduction was performed by the instruments peristaltic pump at 1.0 mL/min and a Meinhard nebulizer which was mounted to a cyclon spray chamber. The measured spectral element lines were Cu: 324.754 nm; Fe: 259.941; Mn: 257.610 nm; Zn: 213.856 nm. The RF power was set to 1000 W, the plasma gas was 15 L Ar/min, whereas the nebulizer gas was 600 mL Ar/min. Regularly after 10 measurements three blank determinations and a control determination of certified element standards (SPEX) were performed. Comparability between the ICP-OES and -MS was checked by analyzing identical rat brain extracts (n = 10) and serum with both detectors in analogy to [83 (link)]. Results showed no significant differences between both metal detectors. The following recoveries (rec.) in ICP-DRC-MS detection were found related to ICP-OES (set 100% ) in rat serum and rat brain extracts: Cu Serum (~60 µg/L): 102 ± 20% rec.; Cu brain extract (~600 µg/kg): 103 ± 14% rec; Fe Serum (~2.5 mg/L): 128 ± 13% rec.; Fe brain extract (~6 mg/kg): 130 ± 14% rec; Mn Serum (~7 µg/L): 101 ± 7% rec.; Mn brain extract (~150 µg/kg): 102 ± 13% rec.; Zn Serum (~1450 µg/L): 82 ± 13% rec.; Zn brain extract (~5 mg/kg): 101 ± 14% rec.

The analysis of the recovered minerals was carried out using inductively coupled plasma optical emission spectroscopy (ICP-OES; PerkinElmer Optima 7300 DV-Germany). The acid digestion followed by ICP-OES was used to determine the concentrations of heavy metals in the precipitates. The strong oxidizing acids used in the digestions process were HCl, HNO₃, and HF added as follows: 6 mL of concentrated HCl, 2 mL of concentrated HNO₃, and 2 mL of concentrated HF. The microwave digestion system MARS 6 (CEM Corporation) was used for sample digestion.