Papers by Author: Zhi Liang Jiang

Abstract: In the media of pH 2.72 HCl-N_aA_c, Fe3O4 nanoparticles in size of 10 nm exhibited strong catalytic effect on the slow reaction of H₂O₂ and the substrate dopamine (DA) to form dark red small molecule polymer particles, which exhibited two absorption peaks at 305nm and 435nm. In the optimum conditions, as the concentration of H₂O₂ increased, the absorption value at 300 nm increased linearly. The increased absorption intensity (ΔA305nm) was linear to the H₂O₂ in the range of 0.5-35 μmol/L, with a linear regression equation of ΔA305nm=0.014C +0.043, a relative coefficient of 0.9997 and detection limit of 0.13 μmol/L H₂O₂, respectively. The proposed method was applied to detect H₂O₂ samples, with satisfactory results.

Abstract: Herring sperm DNA (hsDNA) was used to modify 5 nm nanosilver to obtain a hsDNA-nanosilver probe (Ag-hsDNA) for Hg²⁺. In the presence of Hg²⁺, it combined with hsDNA to produce Hg²⁺-hsDNA complexes and to release nanosilver particles, based on formation of stable T-Hg²⁺-T mismatches. Nanosilver particles aggregated to form larger nanosilver clusters and led the absorption at 412 nm decreased in the pH 6.5 Na₂HPO^4-NaH₂PO₄ buffer solution and 0.05 mol/L NaCl medium. The decreased absorption (ΔA₄₁₂ nm) is linear to Hg²⁺ concentration in the range of 1.36-10.86μg/L Hg²⁺, with regress equation of ΔA=0.0987CHg²⁺ +0.0624, correlation coefficient of 0.9890, and detection limit of 0.30μg/L Hg²⁺. The assay was applied to the analysis of Hg²⁺ in wastewater with satisfactory results.

Abstract: O₃ reacted with KI-H₃BO₃ absorption solution to produce I₂ which can combine with the excess I- to form I₃-. In pH 4.0 HAc-NaAc buffer solution, I₃- reacted with rhodamine 6G (Rh6G) to form Rh6G-I₃ association particles, which exhibited a great decreasing at 525 nm. Under the chosen conditions, the decreased intensity ΔA was linear to I₂ concentration in the range of 0.5×10^-6-33×10^-6 mol/L. Thus, a highly sensitive and selective spectrophotometric method was proposed to detect O₃ in the air, since the concentration of O₃ was equal to that of I₂ in this reacted system.

Abstract: Using sodium citrate as reducing agent, different sizes of gold nanoparticles(GN) were prepared, and were modified by platelet-derived growth factor (PDGF) aptamer to obtain stable aptamer-nanogold probes (Apt-GN). The probe specifically combined with PDGF-AA to form Apt-GN-PDGF-AA clusters that exhibited a resonance Rayleigh scattering (RRS) peak at 550 nm. The RRS intensity ΔI_550nm was linear to the PDGF-AA concentration in the range of 0.33-40 ng/ml. The probe has strong catalysis of the Fehling reagent-glucose Cu₂O particle reaction that can be monitored by RRS technique at 610 nm, but the cluster is very weak. When PDGF-AA concentration increased, the Apt-GN decreased, and the RRS intensity at 610 nm decreased. The decreased RRS intensity ΔI_610nm was linear to PDGF-AA concentration in the range of 0.03-26.67 ng/mL. Accordingly, two new aptamer-nanogold RRS methods were established.

Abstract: The Te particles appear two strong resonance Rayleigh scattering peak at 778 nm and 540 nm. In the HCl medium at 70 oC, rhenium (VII) or Re nanoparticles catalyze the Sn(II) reduction of Te(VI) to form Te particles. The RS intensity at 778 nm enhanced linearly with Re concentration. The enhanced RS intensity was linear Re concentration in the range of 0.01-2.0 nmol/L, with a detection limit of 0.005 nmol/L Re. This method was applied to analysis of Re in real sample, and the results were agreement with that of the spectrophotometry

Abstract: In pH 8.4 Tris-HCl buffer solutions, the alcohol dehydrogenase (ADH) catalyzed the reaction between ethanol and nicotinamide adenine dinucleotide (NAD) to produce acetaldehyde. The acetaldehyde reduce HAuCl4 to form gold particles, and the excess HAuCl4 have enhancement effect on the chemiluminescence reaction of luminol-H2O2. The excess HAuCl4 decreased when ethanol increased, and the chemiluminescence value decreased. Accordingly we can utilize the chemiluminescence to detect the content of ethanol indirectly. The decreased chemiluminescence value (ΔI) was proportional to the ethanol concentration (C) from 0.017 to 5.10 mmol/L, with a regression equation of ΔI = 2374.3C+280.1, and a detection limit of 2.3 μmol/L. This proposed method was applied to detect ethanol in saliva samples of drunk, with satisfactory results

Abstract: Cr(VI); dithiothreitol; Nanogold; Resonance Rayleigh scattering spectral assay. Abstract. Nanogold (NG) in size of 15 nm was prepared by sodium citrate procedure, and it was modified by 1,4-dithiothreitol (DTT) to form NG-DTT probe for Cr(VI). In diluted H2SO4 medium, the probe interacted with Cr(VI) to form big NG clusters that led to the resonance Rayleigh scattering (RS) peak at 720 nm increased greatly. Under the selected conditions, the increased RS intensity (ΔI720nm) is linear to Cr(VI) concentration in the range of 10-50 nmol/L, with a regression equation of ΔI720nm= 2.05 C-7.5, coefficient of 0.9989, and a detection limit of 5 nmol/L. This nanogold RS method was applied to determination of Cr(VI) in waste water samples, with satisfactory results.

Abstract: Nanogold (NG) in size of 10 nm was prepared by the NaBH4 procedure. A new ligand 6-mercaptonicotinic acid (MNA) was used to couple both methylmercury chloride (CH3HgCl) and carrier protein to obtain an immunogen, it was immunized BALB/C mice, and the spleen cells of immunized mice were fused with myeloma cells. The monoclonal antibody (mAb) against mercury (II) ions was produced by the hybridoma technique. The mAb was labeled the NG to prepare an immunonanogold (ING) probe for Hg(II). In pH 5.4 Na2HPO4-citric acid buffer solution and under the condition of ultrasonic irradiation, the ING particles were aggregated un-specifically to form big particles that exhibited a strong resonance Rayleigh scattering (RRS) peak at 580 nm. When the Hg(II) was added, the specific immunoreaction of ING-Hg(II) take place, and the ING-Hg(II) immunocomplex dispersed in the solution that caused the RRS intensity decreasing linearly at 580 nm. The decreased intensity was linear to Hg(II) concentration in the range of 0.025-10 μmol/L, with a detection limit of 1.1 nmol/L Hg(II).

Abstract: Fe₃O₄ nanoparticles were prepared, and catalyzed the reaction of H₂O₂-methyl orange. In pH 1.42 HCl-NaAc buffer solution, methyl orange has two absorption peaks at 331nm and 506 nm. When Fe₃O₄ nanoparticles was added, it can catalyzed H₂O₂ oxidizing methyl orange to result in the absorption value decreased at 506 nm. The decreased absorption value is linear with the concentration of H₂O₂ in the range of 3.5-33 μmol/L. Based on this, a new colorimetric assay has been proposed for the determination of H₂O₂ in the water sample, with satisfactory results.

Abstract: Colloidal Au nanoparticles as active substrate for surface-enhanced resonance Raman scattering(SERRS) were prepared by the trisodium citrate-reduced procedure. In pH 6.6 Na₂HPO₄-NaH₂PO₄ buffer solution and in the presence of aggregation reagent NaCl, nanogolds were aggregated to form stable aggregated- nanogolds (ANG). The crystal violet (CV) adsorbed on the surface of ANG to form CV-ANG conjugates that produce strongest surface-enhanced resonance Raman scattering peak at 1616 cm^-1. In the optimal condition, the SERRS intensity at 1616 cm^-1 was linear to the CV concentration in the range of 2.5×10^-8 -1.75×10^-7 mol/L, a surface-enhanced resonance Raman scattering assay was set up for detection of trace CV, with good selectivity.