[Determination of Trace Boron Based on Gold Nanorod Plasmonic Resonance Rayleigh Scattering Energy Transfer to the Coordinate].

B is a necessary trace element for human and animals, but the excess intake of B caused poison. Thus, it is very important to determination of B in foods and water. The target of this study is development of a new, sensitive and selective resonance Rayleigh scattering energy transfer (RRS-ET) for the determination of B. The combination of energy transfer with resonance Rayleigh scattering (RRS) has developed a new technology called RRS-ET, which can realize selective and sensitive detection of boric acid. The gold nanorods in diameter of 12 nm and length of 37 nm were prepared by the seed growth procedure. In pH 5. 6 NH4 Ac-HAc buffer solution and in the presence of azomethine-H (AMH), the gold nanorod particles exhibited a strong resonance Rayleigh scattering (RRS) peak at 404 nm. In the presence of boric acid, it reacts with AMH to form AMH-boric acid (AMH-B) complexes. When the complexe as a receptor close to the gold nanorod as a donor, the resonance Rayleigh scattering energy transfer (RRS-ET) take placed that resulted in the Rayleigh scattering signal quenching. With the increase of the concentration of boric acid, the formed complexes increased, the scattering light energy of gold nanorod transfer to the complexes increased, resulting in the Rayleigh scattering intensity linearly reduced at 404 nrn. The decreased RRS intensity responds linearly to the concentration of boron over 10~750 ng . mL-1 B, with a regress equation of ΔI404 nm =3. 53c+24 and a detection of 5 ng mL-1 B. The influence of coexistence substances on the RRS-ET determination of 2. 3 X 10(-7) mol . L-1 B was considered in details. Results showed that this new RRS-ET method is of high selectivity, that is, 4 X 10(-4) mol . L-1 Mn2+, Cd2+, Zn2+, Bi+, Na+, Al3+, glucose, Hg2+, IO3-, F-, SO(2-)3, SiO3-, NO3-, CIO4-, H2O2, mannitol, glycerol, and ethylene glycol, 4X 10(-5) mol . L-1 L-tyrosine, and 2 X 10(-4) mol . L-1 L-glutamic acid do not interfere with the determination. Based on this, a new sensitive, selective, simple and rapid RRS-ET method has been developed for the determination of trace boron in six mineral water samples that contain 24. 9, 29. 3, 57. 9, 59. 0, 84. 9, and 105. 1 ng . mL-1 B, with relative standard deviation of 1. 6%~ 4. 1% and recovery of 95. 61~9. 6%.

[Resonance scattering spectral detection of trace K+ by aptamer-modified nanogold probe].

In pH 7.0 Na2HPO4-NaH2PO4 buffer solution, nanogold particles interacted with the aptamer to form a stable aptamer-nanogold complex that was not aggregation by NaCl. At 80 degrees C, K+ and aptamer folded to form a stable G-quadruplex that released nanogold particles, the uncombined nanogold particles aggregated to large nanogold clusters that caused the increase in resonance scattering (RS) intensity at 563 nm in high concentration of NaCl, and the laser scattering showed that the average diameter was 120 nm. In the present paper, the resonance scattering spectral characteristics of K+ -ssDNA1-Au, K+ -ssDNA2-Au and K+ -aptamer-Au systems were investigated, and the structural changes of aptamer were studied by circular dichroism spectral technology. Effects of pH value, NaCl concentration, nanogold concentration, aptamer concentration, and the reactation temperature and time on the resonance scattering intensity were considered in detail. The influence of coexistent substances on the determination of K+ was investigated, result showed that the common heavy metal ions such as Cu2+, Mg2+, Pb2+, Ca2+, Al3+, Zn2+ and Fe3+ do not interfere with the determination, and the method has good selectivity. Under the conditions selected, a 0. 67-3 350 micromol x L(-1) K+ can be detected by the aptamer-nanogold RS assay, with a detection limit of 0.3 micromol x L(-1) K+, regression equation deltaI = 0.167c-0.7, and a coefficient of 0.9932. The method was used for analysis of K+ in serum sample with the results consistent with the ion-selective electrode method.