Tga dsc 3 thermogravimeter

The thermal stability and decomposition characteristics of the dried samples were analyzed using a TGA/DSC 3+ thermogravimeter (Mettler Toledo, Greifensee, Switzerland). Approximately 5 to 7 mg of the material was weighed into 70 µl aluminium oxide crucibles and subjected to heating from 30 to 600 °C at a rate of 5 °C/min in a nitrogen atmosphere (50 ml/min) [35] (link). The TG and DTG curves were derived from the differential values of the mass loss with respect to temperature. Thermograms (TGA/DTG) were assessed using the STAR software (version 16.10) from Mettler Evaluation. Each sample underwent two replicates for robust analysis.

FTIR measurements were carried out in Attenuated Total Reflectance (ATR) mode using the Nicolet iS10 apparatus with an adapter equipped with a diamond crystal (Thermo Scientific). Measurements were carried out in the mid-infrared range (500–4000 cm⁻¹) using: (i) solid samples of nanoparticle powders and (ii) surface modifiers in their pure form. Thermogravimetric analysis (TGA) was carried out using a TGA/DSC3+ thermogravimeter (Mettler Toledo) at a temperature increment 10 °C/min in a temperature window of 25–750 °C and air flow rate 60 mL/min. The total content of C, H, and N elements in modified MNPs was measured using a Vario EL III analyzer with a thermal conductivity detector (Elementar, Langenselbold, Germany) by the accurate weighting of the solid sample and its burning in oxygen at 1150 °C in a dynamic system. Fe, Au, and Si content in solid MNPs was established using the ICP-MS/MS technique, analogically to the methodology presented above (see Section 3.3.2; monitored isotopes: ²⁸Si, ⁵⁶Fe, ¹⁹⁷Au at on-mass mode), but solid samples before digestion were accurately weighted. The oxygen content in the cores of surface-modified MNPs was estimated using the molar ratio of Fe/O in the synthesized bare MNPs as the rest types of the nanomaterials were formed based on such cores (with specific FeO/Fe₂O₃ ratio).