Application Of The Coordination Between Elemental Selenium Nanoparticles And Oxalic Acid, Calcium Oxalate

In this study,Oxalic acid(H₂C₂O₄) was a surface modifier for elemental selenium nanoparticles(nanoSe⁰) in liquid phase.With this in mind,the chemical modulation of CAC₂O₄ crystals morphologies by nanoSe⁰ could be obtained.NanoSe⁰ modified electrode was used as biosensors to detect H₂C₂O₄.It has important significance for the applied field of the nanoSe⁰.The the coordination between H₂C₂O₄ and nanoSe⁰ was studied.The results showed that H₂C₂O₄ could modify nanoSe⁰.NanoSe⁰ - H₂C₂O₄ sol did not deposit in 24 h.It was showed that the nanoSe⁰ were spherical(the size was about 50 nm) and strip(the size was about 200 nm) shapes.When the time increase by degrees after 24 h,the strip(the strip size was about 1μm) accumulation were appeared in nanoSe⁰ - H₂C₂O₄ sol.Fourier transform infrared spectrometry(FTIR) indicated that nanoSe⁰ could coordinate with C₂O₄^2- as C—O—Se and O—Se—O valencies in nanoSe⁰ - H₂C₂O₄ sol.Chemical modulation of calcium oxalate(CAC₂O₄) crystals morphologies by nanoSe⁰ was investigated with scanning electron microscopy(SEM),energy-dispersive X-ray analysis(EDX),Fourier transform infiared spectrometry(FTIR),X-ray diffraction (XRD) analysis and inductively coupled plasma atomic emission spectroscopy (ICP-AES).NanoSe⁰ inhibited the growth of calcium oxalate monohydrate(COM) crystals,prevented the aggregation of COM crystals and induced the formation of the spherical calcium oxalate dihydrate(COD) crystals containing selenium.The results showed that the aggregation of CAC₂O₄ crystals was not affected when nonoSe⁰ was modified by ascorbic acid(Vc) or glucose but a little affected by glycin(Giy).The inhibition of the crystal growth and aggregation of CAC204 crystals by nanoSe displayed concentration effects. The optimal concentration of nanoSe⁰ sol is about 3×10^-5 mol/LSquare Wave Voltammograms(BSWV) determination of H₂C₂O₄ using nanoSe⁰/Vc/SeCys-GC electrode was presented.In 0.1 mol/L H₂SO₄ solution,H₂C₂O₄ yielded a sensitive oxidation peak at 1.37 V on nanoSe⁰/Vc/SeCys-GC electrode.The peak current had a linear relationship with the concentration of H₂C₂O₄ in the range of 2×10^-4～5×10^-2 mol/L and a 3σdetection limit was 2.0×10^-5 mol/L.The relative standard deviation of the oxidation current was 2.9%when using three modified electrodes prepared at different times.Cl^- interfered the experiment and AgNO₃ was used to eliminate it.The content of H₂C₂O₄ in the urine simulation sampleds were determined by BSWV on nanoSe⁰/Vc/SeCys-GC electrode.The ratio of c(H₂C₂O₄) in measure data and c(H₂C₂O₄) in simulation sample were between 0.98～1.01.The content of H₂C₂O₄ in the spinage samples were determined by BSWV on nanoSe⁰/Vc/SeCys-GC electrode.The results showed that in every 100 g spinage there was 470 mg H₂C₂O₄ in the first passel and there was 443 mg H₂C₂O₄ in the second passel. The results of recovery in the spinage samples were between 96.5～108%.Under the decompose temperture of H₂C₂O₄,when the temperature was increased the content of H₂C₂O₄ in the spinage scald solution was increased and the content of H₂C₂O₄ in the spinage after scaldeing was decreased.