4200 mp aes

In triplicate, the ashes of each species were digested with a mixture of 65% nitric acid (HNO₃) and hydrogen peroxide (H₂O₂) 2:1 (v:v) under constant heating until a white homogeneous precipitate was obtained, followed by dilution of the sample in 5% HNO₃. Mineral elements were analyzed using a microwave plasma-atomic emission spectrometer (MP-AES; Agilent 4200 MP-AES, Australia). The blanks values were subtracted to correct the final concentrations of analyzed metals. Results were expressed as mg or μg g⁻¹ wet weight (ww).

Air-dried leaf samples (leaf blades) were ground and dry-ashed in concentrated HNO₃ vapours, and the ash was dissolved in a 3% HCl solution. Wet digestion in H₂SO₄ and HNO₃ was used for N and S detection, respectively. Atomic absorption spectroscopy, using an acetylene-air flame atomizer (Perkin Elmer AAnalyst 700) and microwave plasma atomic emission spectrometry (4200 MP-AES, Agilent), was used for the measurement of K, Ca, Mg, Fe, Mn, Zn, and Cu according to the manufacturer’s instructions. Levels of P, Mo, N, and B were determined by colorimetry: P by ammonium molybdate in an acid-reduced medium, Mo by thiocyanate in a reduced acid medium, B by hinalizarine in a sulphuric acid medium, N by modified Kjeldal method using Nessler’s reagent in an alkaline medium, and S through the turbidimetric method by adding BaCl₂, using a spectrophotometer Jenway 6300 as described previously [60 (link)]. All the values were expressed as mass % and mg kg⁻¹ on a dry matter basis for each macronutrient and micronutrient evaluated, respectively.

Tumor-free mice were injected with 5 mg/kg IONPs and sacrificed 1 h or 24 h after injection (n=5 for each group) by cardiac perfusion with 30 mL PBS under anesthesia. Liver, spleen, kidneys, lungs, and heart were collected, weighted, and digested in aqua regia during 24 h. Quantification of the iron concentration was carried out by atomic emission spectroscopy (Agilent 4200 MP-AES, USA) using the calibration curve for the standard samples in 0.1-1 mg/mL concentration range. Untreated animals (n=5) were used as control for measuring endogenous iron levels. Mean iron levels in control organs were subtracted from corresponding iron levels in MNCb-, MNRd-, and MNCl-treated groups to get IONPs-associated iron concentration (µg/g tissue). IONPs delivery efficiency calculations were based on iron concentration in the tissues, organ mass, and injected dose. For tumor-bearing animals, iron concentration in organs and tumors was measured in untreated and IONPs-treated (5 mg/kg) groups 24 h upon i.v. injection as described above.