[A Facile Nanogold Surface Plasmon Resonance Absorption Method for CO Tracing].

The detection of gas pollutants in atmosphere and indoor air is very important to human health and safety. Monoxide carbon (CO) is a common gas pollutant with high toxicity that mainly comes from the inadequacy oxidization of carbon such as oil, coal and petrol inadequacy combustion, auto-gas and some natural disasters whose limit value in air is lower than 6.0 mg·m-3 in the national standard. Due to its toxicity and uneasy detection, it is one of very dangerous component in the silent killer. Recently, several methods, including infra-red absorption, gas chromatography, potentiometry, Hg replacement, spectrophotometry, I2O5 and PdCl2 nake-eye, semiconductor sensor have been reportedly used for the detection of CO. To our best knowledge, there are no SPR absorption methods for CO, based on the NG SPR absorption. In this paper, the reaction between CO and HAuCl4 was studied with absorption spectrophotometry and transmission electron microscopy (TEM)while a simple and rapid SPR absorption method was developed for the determination of trace CO. In pH 7.2 phosphate buffer solutions, monoxide carbon reduced HAuCl4 to form nanogold (NG) particles with the size of about 45 nm that exhibited surface plasmon resonance (SPR) absorption peak at 540 nm and three energy spectral peaks at 1.70 keV, 2.20 and 9.70 keV for gold element. The analytical conditions were examined, and a pH 7.2 phosphate buffer solution with a concentration of 40 mmoL·L-1 PO3-4, a concentration of 40.0 µg· mL-1 HAuCl4 and a reaction time of 5 min was selected for use. Under the selected conditions, the SPR absorption peak value was linear to CO concentration in the range of 0.2～8.75 µg· mL-1, with a detection limit of 0.1 µg· mL-1 CO. According to the procedure, the influence of coexistent substances on the determination of 1.0 mg·L-1 CO was tested, with a relative error of ±5%. Results indicated that 200 times SO2-3, PO3-4, SO2-4, CO2-3 and NO-3, 100 times Zn2+, K+, BrO-3, Na2S, ethanol, methanol, 80 times Ni2+, Cr3+, Co2+, Ca2+, Mg2+, Fe3+, glucose, Pb2+, Al3+, SeO2-3, Na2S2O3, formaldehyde, 50 times Mn2+ do not interfere with the determination. It showed that this SPR method had good selectivity. The CO content in air samples was determined with the SPR method, with a relative standard deviation (RSD) of 1.8%～4.2%, the SPR method results were agreement with that of the gas chromatography (GC).

[A Hydride Generation-Catalytic Resonance Rayleigh Scattering Method for Detection of Trace Arsenic].

Arsenic is a toxic metal element and the establishment of a highly sensitive and selective method for As has great significance to human health and environment protection. In sulfuric acid medium, As(Ⅲ) was reduced by NaBH4 to form AsH3 gas that was trapped by the Ce(Ⅳ)-I- catalytic absorption solution to cause Ce(Ⅳ) concentration decreased and As particle increased, which resulted in the resonance Rayleigh scattering (RRS) and fluorescence increased at 370 and 351 nm respectively. The increased RRS and fluorescence intensities were linear to As(Ⅲ) concentration in the range of 0.006~0.76 and 0.006~0.28 mg·L(-1) respectively, with a detection of As of 3.0 µg·L(-1). The new hydride generation-catalytic RRS method was applied for detection of trace As(Ⅲ) in milk samples, and the results were in agreement with that of hydride generation-atomic absorption spectrometry.

[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%.

[Fluorescence Determination of Trace Se with the Hydride-K13-Rhodamine 6G System].

Se is a necessary trace element for human and animals, but the excess intake of Se caused poison. Thus, it is very important to determination of Se in foods and water. The target of this study is development of a new, sensitive and selective hydride generation-molecular fluorescence method for the determination of Se. In 0. 36 mol . L-1 sulfuric acid, NaBH4 as reducing agent, Se (IV) is reduced to H2 Se. Usin3-g I solution as absorption liquid3, I- is reduced to I- by H2Se. When adding rhodamine 6G, Rhodamine 6G and I3- form association particles, which lead to the fluorescence intensity decreased. When Se(IV) existing, Rhodamine 6G and I3- bind less, And the remaining amount of Rhodamine 6G increase. So the fluorescence intensity is enhanced. The analytical conditions were optimized, a 0. 36 ml . L-1 H2SO4, 21. 6.g . L-1 NaBH4, 23.3 µm . L-1 rhodamine 6G, and 50 µmol . L-1 KI3 were chosen for use. When the excitation wavelength is at 480nm, the Rayleigh scattering peak does not affect the fluorescence recording, and was selected for determination of Se. Under the selected conditions, Se(IV) concentration in the 0. 02~0. 60 µg . mL-1 range and the increase value of the fluorescence intensity (ΔF) at 562 nm linear relationship. The linear regression equation is ΔF562 nm =12. 6c + 20. 9. The detecton limit was 0.01 µ.g . L-1. The influence of coexistence substances on the hydride generatin-molecular fluorescence determination of 5. 07 X10(-6) mol . L-1 Se(IV) was considered in details. Results showed that this new fluorescence method is of high selectivity, that is, 0. 5 mmol. L-1 Ba2+, Ca2+, Zn2+ and Fe3+, 0. 25 mmol . L-1 . Mg2+, 0. 05 mmol . L-1 K+, 0. 2 mmol . L-1 Al3+, 0. 025 mmol . L-1 Te(VI) do not interfere with the determination. The influence of Hg2+, CD2+ and Cu2+ that precipitate with Se(IV), can be eliminated by addition of complex reagent. This hydride generation-molecular fluorescence method has been applied to determination of trace Se in water samples,

[Resonance Rayleigh scattering determination of trace tobramycin using aptamer-modified nanogold as probe ].

Nanogold (NG) was prepared using NaBH4 reduction of HAuCl4. The NG was modified by the tobramycin-aptamer to obtain a stable Apt-NG probe for tobramycin. The three aptamers containing 15, 21 and 27 bases were examined, and results showed that the aptamer with 21 bases was best and was chosen for use. In pH 6. 8 PBS buffer solution and in the presence of NaCl, the Apt-GN probes were not aggregated. When tobramycin was added, it reacted with the Apt of Apt-NG probe to form a very stable Apt-Tbc complex and released NGs that were aggregated into big particles under the action of NaCl with three resonance Rayleigh scattering peaks at 285, 368 and 525 nm respectively. The resonance Rayleigh scattering peak increased at 368 nm due to the formation of big NG particles from the probe. The effect of pH buffer solution, its volume, and Apt-GN probe concentration on the ΔI value was considered. A 200 µL pH 6. 8 PBS buffer solution and 19. 1 nmol · L(-3) Apt-GN, giving max ΔI value, were chosen for use. Under the chosen conditions, the increased resonance Rayleigh scattering intensity ΔI368 nm was linear with Tbc concentration in the range of 1.9-58.3 ng mL(-3), with a regress equation of ΔI = 35.3c-23 and a detection limit of 0.8 ng · mL(-3) Tbc. A 10.0, 20.0 and 30.0 ng mL-3 Tbc was determined five times respectively, and the relative standard deviations were 6.8%, 5.0% and 4.4%. The influence of some foreign substances was examined on the determination of 38.9 ng · mL(-3) Tbc, within ±10% related error. Results showed that a 80 times of Zn2+, 40 times of L-glutamic acid, Cu2+, Mg2+ and Ca2+, 20 times of glucose and terramycin, 10 times of L-phenylalanine and glycin, 2 times of L-aspartic acid, and 6 times of bovine serum albumin (BSA) and human serum albumin (HSA) do not interfere with the RRS determination of Tbc. The results showed that this aptamer-nanogold RRS method is of good selectivity. Tbc in real sample was analyzed, and the analytical result was in agreement with that of reference results, with a relative standard deviation of 6.5%-7.6% and a recovery of 95.0%-107%.

[Resonance Rayleigh scattering determination of trace ozone based on the cationic surfactant association particles].

In the presence of pH 4.0 HAC-NaAC buffer solution, using H3BO3-KI (BKI) as absorption solution, O3 oxidized KI to produce I2, and it reacted with excess I- to form I3- that combined with the cationic surfactant (CS) such as cetylpyridinium chloride (CPCl), tetradecyl pyridinium bromide (TPB), cetyl trimethyl ammonium bromide (CTMAB), and tetradecyl dimethylbenzyl ammonium chloride (TDMAC) to produce stable (CS-I3)n association particles, which exhibited a strong resonance Rayleigh scattering (RRS) peak at 470 nm. Under the chosen conditions, as the concentration of O3 (C) increased, the concentration of I3- increased, and the RRS intensity at 470 nm (1470 nm) increased due to more association particles forming. The increased RRS intensity I470 nm was linear with O3 concentration. For the four CS systems, the linear range was 15-50, 50-100, 5-25 and 1-50 micromol x L(-1) O3 respectively. The regression equation is delta I = 8.81c-4.01, delta I = 5.44c-3.11, delta I = 15.39c-1.55, and delta I = 16.88c + 0.51. The detection limit is 4.9, 12, 2.85 and 0.56 micromol L(-1) O3 respectively. The influence of some foreign substances was examined on the determination of 2.5 x 10(6) mol x L(-1) O3, within +/- 10% relative error. Results showed that a 4.0 x 10(-5) mol x L(-1) Hg2+, 8.7 X 10(-5) mol x L(-1) Fe3+, 5.0 x 10(-5) mol x L(-1) Ca2+, 2.5 x 10(-5) mol L(-1) Zn2+ and Cu2+, 2.8 x 10(-6) mol x L(-1) Pb2+ and Cr3+, 4.2 x 10(-5) mol x L(-1) Mg2+, Mn2+ and Ba2+ do not interfere with the RRS determination. This showed that this RRS method is of good selectivity. The TDMAC system is most sensitive, and was chosen to detect O3 in air samples. The analytical results were in agreement with that of spectrophotometry results. Further more, laser scattering technique was utilized to examine the particle size distribution of (TDMAC-I3)n system. Results indicated that the particle size located in the range of 190-531 nm, in the absence of O3. Upon addition of O3, the excess KI reacted with O3 to produce I3-, and I3- interacted with the TDMAC to form (TDMAC-I3)n associated particles with a size range of 1,106-3,091 nm. This test identified that there are associated particles in the TDMAC system.

Supramolecular sky-blue phosphorescent polymer iridium complexes for single-emissive-layer organic light-emitting diodes.

Novel supramolecular phosphorescent polymers (SPPs) are synthesized as a new class of solution-processable electroluminescent emitters. The formation of these SPPs takes advantage of the efficient non-bonding assembly between bis(dibenzo-24-crown-8)-functionalized iridium complex monomer and bis(dibenzylammonium)-tethered co-monomer, which is monitored by (1) H NMR spectroscopy and viscosity measurements. These SPPs show good film morphology and an intrinsic glass transition with a Tg of 94-116 °C. Noticeably, they are highly photoluminescent in solid state with quantum efficiency up to ca. 78%. The photophysical and electroluminescent properties are strongly dependent on the molecular structures of the iridium complex monomers.

[DNAzyme cracking-nanogold resonance Rayleigh scattering spectral method for the determination of trace Cu2+].

In the condition of pH 7.0 HEPES buffer solution and 0.19 mol x L(-1) NaCl, the substrate strand DNA (SS) and the enzyme strand DNA (ES) hybridized into a double-stranded DNA (dsDNA) at 80 degrees C. The substrate chain of dsDNA could be cracked by Cu2+, and the released single-stranded DNA (ssDNA) were adsorbed on the nanogold(NG) surface to produce a stable NGssDNA conjugate. The unprotected NG was aggregated to form NG aggregation (NGA) that exhibited a resonance Rayleigh scattering (RRS) peak at 627 nm. When the Cu2+ was added, the NGssDNA increased, and the NGA decreased that caused the RRS intensity decreasing at 627 nm, and the solution color changed from blue to red. The decreased RS intensity deltaI was linear with the Cu2+ was added, the NGssDNA increased, and the NGA decreased that caused the RRS intensity decreasing at 627 nm, the solution color changed from blue to red. The decreased RS intensity deltaI was linear to the Cu2+ concentration in the range of 15-1 250 nmol x L(-1), with a regression equation of deltaI = 0.17c-2.3, coefficient of 0.989 5 and a detection limit of 8 nmol x L(-1) Cu2+. In addition, the influence of foreign substances on the determination of 0.75 micromol x L(-1) Cu2+ was considered. The results show that 3 micro mol x L(-1) Ca2+, Pb2+ and Hg2+, 2 micromol x L(-1) Fe2+, 1 micromol x L(-1) Sn2+, 4 micromol x L(-1) Al3+, 12 micromol x L(-1) Mn2+, 4 micromol x L(-1) Co2+ and Ni2+ did not interfered with the determination. This indicates that this method has good selectivity. This new, rapid, sensitive, selective RRS method was applied to the determination of Cu2+ in water, with satisfactory results.

[Resonance scattering detection of trace Hg2+ using aptamer modified AuSe nanoalloy].

Under the condition of sodium citrate as stabilizer, the gold-selenium (AuSe) nano-alloy was prepared by sodium borohydride reduction procedure, and was modified by single-strand aptamer to obtain an aptamer nano-alloy probe (apta-AuSe) for Hg(II). In pH 6.8 Na2HPO4-NaH2PO4 buffer solution and in the presence of NaCl of 33 mmol L(-1), the Apta-AuSe probe is not aggregation. The apta-AuSe interacts with Hg2+ to form stable double-strand T-Hg(II)-T mismatches and to release AuSe nano-alloy particles from the probe. The released AuSe nano-alloy particles (20:1) aggregated to form bigger clusters that resulted in the resonance scattering (RS) intensity (I590 nm) increasing at 590 nm. The increased intensity delta I590 nm was proportional to the Hg2+ concentration from 1.3 to 1466 nmol L(-1), with a detection limit of 0.74 nmol L(-1). The regress equation was delta I590 nm = 0.603c + 2.0. Thus, a new resonance scattering (RS) spectroscopy of apta-AuSe was applied to the analysis of trace mercury ion. This simple, rapid, selective and sensitive aptamer AuSe nano-alloy RS assay was applied to the determination of Hg2+ in wastewater, with satisfactory results.

[Resonance scattering detection of trace Hg2+ using herring sperm DNA modified nanogold].

In pH 7.0 tris-HCl buffer solutions and in the presence of 0.017 mol x L(-1) NaCl, herring sperm DNA was combined with gold nanoparticles in size of 10 nm to form stable complex, and the NaCl did not cause the aggregation of the gold nanoparticles. Upon addition of Hg2+, that reacted with DNA to form more stable complex of Hg(2+)-DNA, and the gold nanoparticles aggregated to from larger nanogold clusters that led to considerable enhancement of the resonance scattering intensity at 572 nm enhanced considerably. The effect of GN concentration, DNA concentration, NaCl concentration, incubation time, and temperature, and ultrasonic irradiation was considered respectively, the conditions of 3.87 microg x mL(-1) GN, 11.7 microg x mL(-1) DNA, pH 7.0 Tris-HCl buffer solutions, 17 mmol x L(-1) NaCl, and incubation 10 min at 37 degrees C under the ultrasonic irradiation were chosen for use. Under the conditions, the enhanced resonance scattering intensity at 572 nm was linear to the Hg2+ concentration in the range of 3.3-3 333.3 nmol x L(-1), with regress equation of delta572 nm = 0.019c+5.0, coefficient of 0.999 1, and a detection limit of 2.5 nmol x L(-1) Hg2+. Results of interference tests showed that 30 micromol x L(-1) Mn2+, 33 micromol x L(-1) Mg2+ and Zn2+, 100 micromol x L(-1) Cd2+, 200 micromol x L(-1) Fe3+, and 420 micromol x L(-1) Mo6+, Pb2+ and Cu2+ did not interfered with the determination of 0.33 micromol x L(-1) Hg2+. That is, this resonance scattering spectral assay is of good selectivity. This assay was applied to the detection of Hg(II) in water sample, with a relative standard deviation of 5.1%, and the results were in agreement with that of the cool vapor atomic absorption spectrophotometry.

[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.

[Fluorescence analysis of trace glucose using glucose oxidase and horseradish peroxidase].

In acetate buffer solution and in the presence of glucose oxidase (GOD), glucose reduced the dissolved oxygen to form H2O2 that oxidized catalytically the excess KI to from I3- by horseradish peroxidase (HRP). The I3- combines respectively with rhodamine S (RhS), rhodamine 6G(Rh6G), butyl-rhodamine B(b-RhB) and rhodamine B(RhB) to form RhS-I3, Rh6G-I3, b-RhB-I3 and RhB-I3 associated particles that result in fluorescence quenching at 556, 556, 584 and 584 nm, respectively. Under the optimal conditions, the concentration of glucose in the range of 0.083-9.99, 0.17-8.33, 0.33-8.33 and 0.33-9.99 micromol x L(-1) is linear with their fluorescence quenching at 556, 556, 584 and 584 nm, with detection limits of 0.059, 0.17, 0.21 and 0.16 micromol x L(-1) glucose. And the regression equation was deltaF = 40.0c + 3.0, deltaF = 23.9c + 8.1, deltaF = 25.6c + 4.2, and deltaAF = 18.4c + 0.8, respectively. The RhS system was the most sensitive and stable, and was chosen for use. Influence of some foreign substances on the RhS fluorescence quenching determination of 6.67 micromol x L(-1) glucose was examined, with a relative error of +/- 10%. Results showed that 1000-fold Mg2+ and Cu2+, 300-fold Mn2+, 100-fold Zn2+, Al3+ and Co2+, 60-fold L-tyrosine, urea and nicotinic acid, 50-fold Fe3+, HSA and BSA, 10-fold sucrose, vitamin B2, L-lysine, L-glutamic acid and L-cystine did not interfere with the determination. This RhS fluorescence quenching assay was applied to the determination of glucose in the serum samples with satisfactory results.

[Fluorescence quenching assay of ultratrace horseradish peroxidase using rhodamine dye].

In acetate buffer solution, the reaction of H2O2 with KI was catalyzed by horseradish peroxidase (HRP) to form I3-. The I3- combined respectively with rhodamine S(RhS), rhodamine 6G(Rh6G), rhodamine B(RhB) and butyl-rhodamine B(b-RhB) to form RhS-I3, Rh6G-I3, RhB-I3 and b-RhB-I3 association particles, resulting in the fluorescence quenching at 580, 580, 554 and 554 nm, respectively. The effect of pH value, rhodamine dye concentration, KI concentration, H2O2 concentration, reaction temperature and time on the fluorescence quenching intensity (deltaF) of the four catalytic systems was considered respectively. For the RhS, Rh6G, RhB and b-RhB catalytic systems, pH 4.6-3.2 x 10(-5) mol x L(-1) RhS-4 x 10(-3) mol x L(-1) KI-1.30 x 10(-5) mol x L(-1) H2O2-25 degrees C-20 min, 4.8-2.4 x 10(-5) mol x L(-1) Rh6G-4 x 10(-3) mol x L(-1) KI-2.59 x 10(-5) mol x L(-1) H2O2-25 degrees C-20 min, 4.6-1.6 x 10(-5) mol x L(-1) RhB-4 x 10(-3) mol x L(-1) KI-2.16 x 10(-5) mol x L(-1) H2O2-25 degrees C-20 min, and 4.6-1.6 x 10(-5) mol x L(-1) b-RhB-4 X 10(-3) mol x L(-1) KI-3.02 x 10(-5) mol x L(-1) H2O2-25 degrees C-20 min were chosen for use respectively. Under the optimal conditions, the HRP linear range was 8-6 400 pg x mL(-1) for the RhS catalytic system, 40-4 000 pg x mL(-1) for the Rh6G catalytic system, 32-3 200 pg x mL(-1) for the RhB catalytic system and 40-6 400 pg x mL(-1) for the b-RhB catalytic system, with a detection limit of 3.2, 3.0, 2.4 and 3.7 pg x mL(-1) HRP, respectively. The regress equation of the four catalytic systems was deltaF = 0.061 1c+39.6, deltaF = 0.047 2c+50.4, deltaF = 0.138 6c+34.2 and deltaF = 0.026 25c+36.72, with a correlation coefficient of 0.997 9, 0.999 0, 0.997 3 and 0.996 9, respectively. The RhS catalytic system was most sensitive, and was chosen for the determination of HRP. The influence of foreign substance on the RhS assay of 3.5 ng x mL(-1) HRP was examined, with a relative error of +/- 10%. A 3000-times L-glutamic acid, L-lysine, Ca2+, Mg2+, Cu2+, Fe3+, Zn2+ and vitamin B6, 1000-times HAS etc did not interfere with the assay. This showed that the assay has good selectivity. The RhS fluorescence quenching assay was applied to the determination of HRP in the solution of hepatitis B surface antibody labeling HRP, with satisfactory results.

[Resonance scattering spectral properties of CdTe nanoparticles and its application].

In the present paper, CdTe quantum dots were prepared, and the resonance scattering, fluorescence and absorption spectral properties of CdTe quantum dots in aqueous solution were studied in details. The fluorescence spectral results showed that the CdTe quantum dots of 3.8, 4.0 and 4.6 nm in diameter have fluorescence peaks at 601, 625 and 654 nm, respectively, the fluorescence peak (lambda F) red shifts, and the fluorescence intensity is proportional to the CdTe concentration. The linear relationship was found between the fluorescence peak wavelength and the logarithm of the diameter. The relationships was lambda F = 126.74 ln(d) + 395.92, with a related coefficient of 0.9945. For CdTe quantum dots of 3.8 nm in size, the fluorescence intensity at 601 nm was proportional to the concentration in the range of 11.25-540 micromol x L(-1). The regression equation is F601 nm = 0.7223c + 3.28, with a correlation coefficient of 0.9980. The absorption spectral results showed that the CdTe quantum dots of 3.8, 4.0 and 4.6 nm in diameter have absorption peak at 550, 573 and 590 nm, respectively. The absorption value is proportional to CdTe quantum dots concentration. For CdTe quantum dots of 3.8 nm in size, the concentration in the range of 11.25-180.0 micromol x L(-1) obeys Lamb-Beer's law. The absorption peak (lambda A) also red shifted and widened, absorption value decreased with the diameter (d). The linear relationship was found between the absorption peak wavelength and the logarithm of the diameter. The relationships was lambda A = 155.01 ln(d) + 415.52, with a related coefficient of 0.9956. The resonance scattering (RS) spectra showed that the CdTe quantum dots of 3.8, 4.0, 4.6, 4.8, 5.2, 6.5 and 8.6 nm in diameter have resonance scattering peaks at 597.94, 622.02, 645.94, 654.05, 656.95, 700.98, 735 nm respectively. The RS peak wavelength lambda R is also proportional to the logarithm of the diameter of CdTe quantum dots. Its regression equation is lambda R = 148.37 ln(d) + 418.08 and the correlation coefficient is 0.9952. For CdTe quantum dots with the same diameter such as 3.8 nm, the resonance scattering intensity at 597 nm is proportional to the CdTe concentration. The linear range is 22.5-180.0 micromol x L(-1), the regression equation is I597 nm = 0.5721c + 5.884, and the correlation coefficient is 0.9975. A new resonance scattering method was applied to the determination of the diameter of CdTe quantum dots, with the advantages of simplicity, quick operation and good practical values.

[Resonance scattering spectra of apolipoprotein immunocomplex particles and its analytical application].

In pH 6.8 Na2 HPO4-NaH2PO4 buffer solution and in presence of polyethylene glycol (PEG), apolipoprotein AI (ApoAI) and apolipoprotein B (ApoB) would combine with their corresponding antibody and produced immune complex particles in size of about 180 nm and 140 nm respectively, which exhibit stronger resonance scattering (RS) effect at 340 nm and 470 nm. The influence of pH, antisera volume, PEG concentration, incubation time and co-exists substances was considered. Under the optimal conditions, the RS intensity is proportional to the concentrations of ApoAI and ApoB when their concentration is in the range of 8.4-430.0 ng x mL(-1) and 14.8-590.0 ng x mL(-1), respectively. The detection limits (DL) are 6.2 ng x mL(-1) for ApoAI and 7.0 ng x mL(-1) for ApoB. The method was successfully applied to determination of ApoAI and ApoB in human serum samples, with satisfactory results.

[Immunoresonance scattering spectral assay of complement factor 4(C4)].

Based on resonance scattering (RS) effect of immune complex particles, a new resonance scattering method for the determination of C4 in the human blood serum was developed. It was based on the fact that goat anti-human C4 was combined with complement factor 4 (C4) in the pH 7.3 Na2 HPO4-KH2PO4 buffer solution. It is known that antibody has C-terminal and N-terminal, and the N-terminal is the binding site of antigen and it could combine with antigen. Because the stereo structure anastomoses and the charge is opposite between goat ant-human C4 and C4, they could attract and combine with each other. The attraction and combination have high idiosyncrasy and they are done by Van der Waals force, hydrophobic force, Coulomb attracting force and hydrogen bond binding force, and form immune complex particles that exhibit three resonance scattering peaks at 350, 390 and 440 nm, respectively, in the presence of PEG-6000. The laser scattering results indicate that the average diameter of the immune complex particles is about 3 440.0 nm. The influence of pH, goat anti-human C4 and PEG-6000 concentration, incubation temperature and incubation time, foreign substance such as arginine, -phenyl alanine, L-glutamic acid, L-cystine, L-threonine, L-tryptophan, L-histidine, L-leucine, glucose, EDTA, human serum albumin (HSA), bovine serum albumin (BSA), L-proline, L-lysine on the determination of C4 was considered in details. Under the conditions chosen, C4 concentration in the range from 0.18 to 2.60 microg x mL(-1) is proportional to the resonance scattering intensity at 350 and 390 nm. Its regression equation is deltaI350 nm = 28.23c + 9.17 and deltaI390 nm = 31.36c + 11.08, the correlation coefficient is 0.993 9 and 0.992 3, and the detection limit is 0.084 microg x mL(-1) and 0.11 microg x mL(-1), respectively. The method has been applied to the determination of C4 in the human blood serum, and the results are in agreement with that of the immunoturbidity, with relative standard deviation of 1.88%-4.36%, and with some advantages including simplicity, rapidity, high sensitivity and selectivity.

A novel and highly sensitive resonance scattering spectral assay for horseradish peroxidase using cationic surfactant.

A novel and ultrasensitive resonance scattering (RS) spectral assay was proposed for detection of horseradish peroxidase (HRP) activity. It was based on that the HRP strongly catalyze H2O2 oxidation of excess I- to form I3-, the resulting I3- combined with four cationic surfactant (CS), including tetradecyl pyridinium bromide (TPB), cetyltrimethyl ammonium bromide (CTMA), cetylpyridinium chloride (CPCM) and tetradecyl dimethylbenzyl ammonium chloride (TDMBA) to produce association particles (TPB-I3)n, (CTMA-I3)m, (CPCM-I3)l and (TDMBA-I3)k, which exhibit a strongest resonance scattering peak at 478, 423, 538 and 491 nm, respectively. For the four systems of TPB, CPCM, CTMBA and TDMBA, the HRP activity determined was in the linear range of 0.004-5.6, 0.04-3.2, 0.04-8.0, 0.08-8.0 ng/mL, with a detection limit of 0.0034, 0.040, 0.033, 0.016 ng/mL, respectively. The TPB resonance scattering spectral assay was best and has been applied to the analysis of HRP in real samples, with satisfactory results.

An immunonanogold resonance scattering-quenching probe for rapid and sensitive assay of microalbumin.

A novel and sensitive immunonanogold resonance scattering (RS) spectral probe was obtained for rapid detection of microalbumin (Malb), using 10 nm gold nanaoparticle to label goat anti-human Malb. It was based on that the gold-labeled anti-Malb took place nonspecific aggregation and exhibited a strong RS peak at 577 nm in pH 5.2 C(6)H(8)O(7)-Na(2)HPO(4) buffer solution containing polyethylene glycol (PEG), and the immunocomplex formed after specific reaction of gold-labeled anti-Malb with Malb, which led to a decrease in the intensity of RS peak at 577 nm considerably. The decreased RS intensity at 577 nm (DeltaI (577nm)) was linear to the concentration of Malb in the range of 4-128 ng/mL, with a detection limit of 3.2 ng/mL. The proposed method was applied to detect Malb in healthy human urine samples with satisfactory results.

[Immunonanogold catalytic spectrophotometric determination of trace complement 3].

Gold nanoparticles about 10 nm in size were prepared by improved trisodium citrate reduction procedure, and were used to label goat anti-human C3 to obtain a sensitive spectral probe for complement 3 (C3) in the condition of pH 7.5. The immune reaction between nanogold-labeled C3 antibody (anti-C3) and the antigen C3 took place to form the nanogold immune complex in pH 5.6 Na2 HPO4-C6H8O7 buffer solution and in the presence of polyethylene (PEG). The optimal immunoreaction conditions were pH 5.6-9.7 microg x mL(-1) nanogold-labeled anti-C3, 6.0% PEG 6000 and incubation time 15 min under ultrasonic irradiation. After centrifuging for 10 min at 12 000 r x min(-1), the excess nanogold-labeled anti-C3 in the upper solutions was obtained, and was used to catalyze the colored particle reaction between HAuCl4 and NH2 OH x HCl to produce gold particles with bigger size. The influence on the immunonanogold catalytic reaction was considered spectrophotometrically. A pH 2.97 Na3C6H5O7-HCl buffer solution, 53.33 microg x mL(-1) HAuCl4, 74.13 microg x mL(-1) NH2OH x HCl, and reaction time of 3 min at 37 degrees C water bath were chosen for use. Results demonstrated that with increasing C3, the concentration of gold labeled anti-C3 in the upper solution decreased, and the absorbance decreased linearly. Linear relationships between the decreased absorbance and the C3 concentration in the range of 0.025-0.60 ng x mL(-1) were obtained by spectrophotometry at 760 nm. The regress equation was deltaA760 nm = 0.276c+0.025 4, the correlation coefficient was 0.990 3, and the detection limit reached 0.007 2 ng x mL(-1) of C3. The influence of foreign substances such as HAS, BSA, and ammonia acid on the determination of 0.2 ng x mL(-1) of C3was examined. Results showed that this assay has high selectivity. The sensitive, rapid and highly specific assay was applied to the quantification of C3 in human sera, with satisfactory results.

An immunonanogold resonance scattering spectral probe for rapid assay of human chorionic gonadotrophin.

BACKGROUND: Several assays for human chorionic gonadotrophin (hCG) such as radioimmunoassay and fluorescence immunoassays were reported. So far, there was no report about the immunonanogold resonance scattering spectral (ING-RSS) assay based on the immunoreaction and resonance scattering (RS) effect. METHODS: Three ING-RSS probes for hCG were prepared, using nanogold in size of 8, 10, 13 nm to label rabbit hCG antiserum (anti-hCG). RESULTS: In citric acid-Na(2)HPO(4) buffer solution and in the presence of polyethylene glycol (PEG)6000, the immunoreaction between hCG and nanogold-labeled anti-hCG took place, the immunonanogold-complex was formed and deposited. The decreased intensity DeltaI(RS) for the nanogold in sizes of 8, 10, 13 nm was proportional to hCG concentration in the ranges of 40-10000, 40-10000 and 40-8000 mIU/ml, with the detection limits of 19.4, 15.1 and 13.6 mIU/ml, respectively. The hCG in urine samples were assayed by the ING-RSS assay, and by immunospectrophotometry. The results of both assays showed a close correlation. CONCLUSION: This assay has simplicity, sensitivity and good selectivity for quantitative determination of hCG.