Optima 5300 dv spectrometer

Leaching tests were performed on different replicated samples in order to verify the amount of silicon, calcium, sodium, phosphorus and cerium released during the cellular tests. The obtained solutions were analyzed through Inductively Coupled Plasma Optical Emission Spectrometry (ICP-OES) for the determination of silicon, calcium, sodium and phosphorus with the Optima 5300 DV spectrometer (Perkin Elmer, Shelton, CT, USA), and through Inductively Coupled Plasma Mass Spectrometry (ICP-MS) for cerium by means of an HR-MC-ICPMS Neptune (Thermo Fisher Scientific Instrument, Bremen, Germany).
In particular, glass disks were soaked in DMEM with a glass surface area/DMEM volume ratio of 6 cm²/mL at different times (1 and 72 h) and 37 °C. The ratio between surface sample area and DMEM equal to 6 cm²/mL was chosen to apply the same conditions as the cellular tests proposed in the method ISO 10993-5 [34 ]. Then disks were separated from the DMEM extracted solution by filtration using a 0.22 micron filter (Merck Millipore, Darmstadt, Germany) in order to eliminate the possible glassy debris particles larger than 0.22 micron that could be formed during the tests. Each solution was analyzed and silicon, sodium, calcium, phosphorus and cerium concentrations are expressed as mean value with 5% of SD over the replicates.

The fabricated materials were characterized using XRD and FTIR at various stages of technology and investigation. XRD patterns of the samples preliminarily ground into powder were obtained using Shimadzu XRD-6000 diffractometer (Kyoto, Japan) with Cu Kα radiation (λ = 1.5418 Å), 40 kV, and 200 mA. The angular-analyzed interval 2Theta was from 4 to 60°, with a step of 0.02°, and speed of the counter was 2°/min. The phases were identified according to JSPDS. FTIR spectra of the materials were recorded using a Bruker Vertex 70V vacuum IR spectrometer (Billerica, MA, USA) in a range of 400–4000 cm⁻¹ with a resolution of 4 cm⁻¹ using the ATR device in Transmission mode. The specific surface area (SSA) of the materials was measured using Brunauer–Emmett–Teller (BET) method using the TriStar 3000 Micromeritics analyzer (Atlanta, GA, USA). The microstructure study of the materials was performed with scanning electron microscopy (SEM) using Tescan Vega II (Brno, Czech Republic), and the samples were previously coated with gold using Q150R device, Quorum Technologies (Ashford, England). The element content (calcium (Ca), phosphorus (Pi), platinum (Pt)) was analyzed for ceramic samples previously dissolved in HCl or for samples of incorporative solutions by inductively coupled plasma atomic emission spectroscopy (ICP-AES) using Perkin Elmer Optima 5300DV spectrometer (Waltham, MA, USA).

Aorta and heart were removed at sacrifice, lyophilized for 24 h and weighed. Lyophilized organs were digested using a 1:1 HNO₃:HClO₄ mixture in a dry bath incubator for 2–4 h at 180°C and subsequently diluted with MilliQ^™ water to a final volume of 10 ml. Calcium and phosphorus contents in serum, heart and aorta were quantified via inductively coupled plasma optical emission spectrometry (ICP-OES) (Perkin-Elmer SL, Optima 5300DV spectrometer)[26 (link)].

The left kidneys were lyophilized, weighed, and digested in a dry bath at 180°C using a 1 : 1 HNO₃ : HClO₄ mixture until the solution was clear. For chemical analysis, digested samples were diluted with distilled water until 10 mL of solution was obtained, and the concentrations of calcium, phosphorus, and magnesium determined using inductively coupled plasma atomic emission spectrometry (PerkinElmer SL, Optima 5300 DV Spectrometer) and the appropriate calibration curve. The concentrations of calcium and other elements were determined as mg/g kidney dry weight.

Mineral composition of petals were determined using Inductively coupled plasma-optical emission spectroscopy (ICP-OES). Samples were prepared by wet burning by adding 8 mL nitric acid + 2 mL H₂O₂ to 0.5 g of a sample using ETHOS ONE (Milestone, Italy) microwave sample preparation according to EPA 3015 method, and the final volume was completed to 20 mL with distilled water. Measurements in ICP-OES were performed using Optima 5300 DV Spectrometer (Perkin Elmer, USA) according to EPA 6010 method. In the petals, each element was measured at a specific wavelength (Al: 396.1, Ca: 317.9, Hg: 253.6, Cd: 228.8, Cr: 267.7, Cu: 327.4, Fe: 238.2, K: 766.5, Mg: 285.2, Mn: 257.6, Na: 589.6, P: 213.6, Se: 196.0, Si: 251.6 and Zn: 206.2 nm).

The collected silica nanoparticles were extracted from the above-described filters with a manual procedure. Firstly, the filters were removed from the plastic holder and placed in 150 mL glass beakers. To each beaker, 5 mL of 1% ethanol was added, then the filters were shaken 3 times using a Vortex-Genie 2 Digital (Scientific Industries, Bohemia, NY, USA) device for 30 s at a speed of 2500 rpm. After shaking, the filters were left overnight to dry. Silica marker extraction from every filter was performed for four days running, so finally 24 liquid extracts with different silica concentrations were obtained. These were marked as R1a ex1, R1a ex2, R1a ex3, R1a ex4, R1b ex1, etc., as shown in Table 4. In the next step, the silicon content in liquid extracts was determined. For this purpose, the extracts were diluted using high-purity deionized water (conductivity below 0.05 µS/cm, Direct-Q3 UV, Millipore) and an internal standard certified silicon solution was added (AccuStandard, New Haven, CT, USA). The silicon was measured in the form of SiO₃₂- using inductively coupled plasma optical emission spectrometry with the application of an Optima 5300 DV spectrometer (Perkin Elmer, Waltham, MA, USA) according to ISO standard 11885:2009 [41 ].

We load the PtCo alloy nanoparticles on carbon supports for the tests of their electrochemical behaviors toward MOR. We add a calculated amount of carbon powers to the PtCo colloidal solution in toluene, and stir the mixture for 24 h at room temperature. We subsequently collect the carbon-supported PtCo nanoparticles (labeled as PtCo/C) by centrifugation, wash them thrice with methanol, and dry them in vacuum at ambient temperature. The mass loading of Pt₃Co on the carbon supports was determined to be 11.8% by inductively coupled plasma atomic emission spectrophotometry (ICP-AES, Perkin-Elmer Optima 5300DV spectrometer). Then we re-disperse the PtCo/C catalysts into 20 mL of acetic acid by ultra-sonication, and reflux the mixture for 3 h at 120 °C to remove the capping agents from the particle surface^{43 (link)}. Finally, we recover the PtCo/C catalysts from acetic acid by centrifugation, wash them thrice with water, and dry them at room temperature in vacuum.