Cd no3 2

For all experiments, double deionized water was used. All chemicals used were of analytical reagent grade and used as received with no further purification, obtained from commercial sources. Urea, trisodium citrate, and boric acid were purchased from Sigma-Aldrich. Fluorescein was purchased from Sigma-Aldrich, Ethanol (99.8%), hydrochloric acid (36–38%), Nitric acid (68–70%), NaOH, (NH₄)₂Fe(SO₄), Fe(NO₃)₃, Mg(NO₃)₂, Al(NO₃)₃, Cu(NO₃)₂, Zn(NO₃)₂, Pb(NO₃)₂, NiSO₄, AgNO₃, CrCl₃, MnCl₂, Cd(NO₃)₂, HgCl₂, Co(NO₃)₂, NaCl, Na₂SO₄, Na₂CO₃, KI, KBr, Na₂S, CH₃COONa, D-glucose, Glycine, and Creatinine were purchased from Sigma-Aldrich. The sera were from regular patients collected from Pediatric Teaching Hospital in the Sulaimani City, Kurdistan Region, Iraq.

Cadmium Nitrate was selected as reference toxicant. Cd(NO₃)₂ was purchased from sigma Aldrich (St. Louis, MO, USA). It is commercially available in a 2% HNO₃ standard solution for AA at 1000 ppm concentration. Stock solutions of Cadmium Nitrate at 100 ppm were prepared in 0.22 µm FNSW (Filtered Natural Sea Water) (Piazza et al. 2012 (link)) at the following concentrations: 0; 0.2; 0.4; 0.8; 1.6; 3.2 mg/L.

The stock solutions of each metal ion (Cd²⁺, Cu²⁺, or Pb²⁺) with a concentration of 1000 mg/L are prepared separately by dissolving a specific amount of the corresponding metal salt (Cd(NO₃)₂, CuSO₄ 5H₂O, or Pb(NO₃)₂, purchased from Sigma–Aldrich (Darmstadt, Germany) and Solvachim (Casablanca, Morocco) in distilled water. The desired working concentrations are prepared by diluting the stock solutions.

Rhodamine B, ethylene diamine, exo-3,6-Epoxy-1,2,3,6-tetrahydrophthalic anhydride, triethyl amine and Hoveyda-Grubbs 2nd generation catalyst (HG2). All metal nitrate salts such as NaNO₃, KNO₃, Mg(NO₃)₂, Al(NO₃)₃, Cu(NO₃)₂, Zn(NO₃)₂, Co(NO₃)₂, Ni(NO₃)₂, Zr(NO₃)₃, Ce(NO₃)₃, La(NO₃)₃, Cd(NO₃)₂, Hg(NO₃)₂, Pb(NO₃)₂ and LiNO₃ were purchased from Sigma-Aldrich. Solvents were purified by standard techniques prior to use for all synthesis. ¹H NMR and ¹³C NMR spectra were recorded on AV 400 MHz Bruker or AV 600 MHz Bruker NMR spectrometer using CDCl₃ and CD₃CN as the solvent at 298 K. Tetra methyl silane (TMS) as an internal standard for ¹H NMR. GPC analysis were carried out using a Viscotek GPC Max VE 2001 instrument with Viscotek TDA 302 tripe array detector Viscotek Org Guard column. UV–Vis spectra were recorded on a Perkin Elmer Lambda 950 UV–Vis spectrometer, using quartz cells of 10 mm path length at 273 K. Fluorescence emission spectra were recorded on Cary eclipse fluorescence spectrophotometer, using quartz cells of 10 mm path length at 273 K. IR spectra on Perkin Elmer FT-IR spectrometer, DSC spectra on Perkin Elmer Jade DSC and TGA on Perkin Elmer Pyris 6 were recorded.

Regarding the contamination by heavy metal ions, the tests were conducted using the following salts: NaAsO₂ and Cd(NO₃)₂ (purchased from Sigma Aldrich (Milan, Italy) and used without further purification). For these solutions, deionized water was used (electrical resistivity 18.2 MΩ*cm at room temperature). UV-vis spectra were performed by using single-use UV-PMMA cuvettes with Perkin-Elmer Lambda 750 UV-vis-NIR for sensing test characterization. Protocol of sensing tests: a fixed volume of our AgNPs (1.6 mg/mL) was mixed with a fixed volume of heavy metal ions solution at a specific concentration and, after 5 minutes of interaction, the optical absorption spectra were collected. This protocol described here was successfully tested on silver nanoparticles, stabilized by the hydrophilic ligand sodium 3-mercapto-1-propanesulfonate, whose response to several metal ions at different concentrations in the range of few ppm was tested by UV-vis spectroscopy [16 (link)].