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High pure ZnO Colloidal nanocrystal clusters (CNCs) were synthesized by a modified hydrolyzation method. The diameters of as-prepared ZnO crystalline were between 20 and 40 nm, however, the ZnO CNCs arrived at 400–800 nm. The ZnO CNCs sensor were found to have high sensitivity and fast response/recovery time to humidity, and their resistance changed approximately three orders of magnitude from about 1.58 × 10 9 Ω in dry air (10 RH%) to 1.65 × 10 6 Ω in 93 RH% air. Furthermore, the ZnO CNCs sensors were relatively stable to humidity for a long time.

MnF2 nanocrystals were prepared by a solvothermal method. Its powder X-ray diffraction (XRD) pattern was indexed to the rutile-type structure with lattice constant a=4.857 and c=3.309 A. The as-prepared MnF2 nanocrystals were spherical particles with a size of 40–60 nm by scanning electron microscopy analysis. Its optical absorption spectrum exhibited absorption features of Mn2+ d−d transitions. The magnetic characterization indicated that the nanocrystals have antiferromagnetic–paramagnetic phase transition at 70.1 K and linear magnetization behavior at 2 K. The electronic structure of tetragonal MnF2 was studied by spin-polarized first-principle density-functional calculation with general gradient approximation (GGA) and pseudopotential localized basis sets, which shows that rutile-type MnF2 should be a three-dimensional paramagnetic insulator. Density of states (DOS) analyses indicate that the manganese 3d orbitals with α and β spin characters dominate the highest valence and lowest conduction bands, respectively. According to the calculated band structure, the optical absorption properties are attributed to d−d transition of the manganese ions. The agreement between simulated and observed absorption spectrum was obtained, which confirms that the present calculated results provide a reasonable description of the electronic structure of rutile-type MnF2.

A lanthanide sensitized chemiluminescence method of flow-injection was developed for the determination of a new fluoroquinolone, ulifloxacin (UFX), and its prodrug prulifloxacin (PUFX). The proposed method was based on the remarkable chemiluminescence enhancement effect of UFX (PUFX) on KMnO4−Na2S2O4−Ln(III). Tb(III) ion was chosen from lanthanides because it showed the best sensitizing effect. Under optimized experimental conditions, the relative chemiluminescence intensity was in linear relationship with UFX and PUFX concentrations in the ranges of 1.0 × 10−8 − 5.0 × 10−6 M and 9.0 × 10−9 − 5.0 × 10−6 M, respectively. The minimum detectable value and relative standard deviation were 5.5 × 10−9 M, 1.5% for UFX and 7.0 × 10−9 M, 2.9% for PUFX, respectively. The proposed method was applied to the determination of UFX in spiked human serum and urine, and of PUFX in tablets with satisfactory results. The possible mechanism of chemiluminescence was also proposed.

This paper reports a flow-injection chemiluminescence method for the determination of ofloxacin (OFLX) using the Ru(bpy)2(CIP)2+-Ce(IV) system. Under the optimum conditions, the relative CL intensity was proportional to the concentration of OFLX in the range 3.0 x 10(-8)-1.0 x 10(-5) mol/L and the detection limit was 4.2 x 10(-9) mol/L. The proposed method has been successfully applied to the determination of ofloxacin in pharmaceuticals and human urine. The chemiluminescence mechanism of the system is also discussed.

This is the first report of terbium(III) as a probe of second-order scattering (SOS) for the determination of proteins in human serum at nanogram levels. A sensitive method has been developed using light scattering, based on the fact that the weak SOS of proteins can be enhanced in the presence of terbium(III) and sodium dodecyl sulphonate (SDS). With this method, 7.0 x 10(-9)-1.0 x 10(-5) g/mL human serum albumin (HSA) and 5.0 x 10(-9)-5.0 x 10(-6) g/mL gamma-globulin can be determined; the detection limits were 4.4 ng/mL for HSA and 3.1 ng/mL for gamma-globulin. The method has been applied to the detection of total proteins in human serum samples, and the results are consistent with those obtained by the Coomassie brilliant blue (CBB) G-250 assay.

The nano-Ag-terbium(III)-mucleic acids system was observed by a resonance light scattering (RLS) technique for the first time, and the quantitative analysis of nucleic acids at nanogram levels was established. Studies showed that the RLS intensity of the nano-Ag-terbium(III) system can be obviously enhanced by nucleic acid, which was characterized by the RLS spectrum and the UV-Vis spectrum. In this system, the nanoparticles were only of a definite size and in a limited particle concentration region. Further research indicated that under the optimum conditions, the enhanced intensity of RLS is in proportion to the concentration of nucleic acids in the ranges of 7.0 x 10(-9) g ml(-1) to 8.0 x 10(-6) g ml(-1) for calf thymus DNA (ctDNA), 2.0 x 10(-8) g ml(-1) to 1.0 x 10(-6) g ml(-1) for fish sperm DNA (fsDNA) and 1.0 x 10(-9) g ml(-1) to 1.0 x 10(-7) g ml(-1) for yeast RNA (yRNA). The detection limits were 1.4 ng ml(-1) for ctDNA, 1.2 ng ml(-1) for fsDNA and 0.85 ng ml(-1) for yRNA, respectively. Synthetic and real samples were determined satisfactorily.

Quinolones (Qs) can form the complex with Tb(III) ion, and the intramolecular energy transfer from Qs to Tb(III) takes place when excited. And thus the characteristic fluorescence of Tb(III) ion was enhanced and the maximum fluorescence peak locates at 545 nm. The second-order scattering (SOS) peak at 545 nm also appears for the Tb(III)–Qs complexes with the exciting wavelength of 274 nm. When the silver nanoparticles were added to the Tb(III)–Qs system, the luminescence intensity at 545 nm greatly increased. And the relative intensity is proportional to the amount of Qs. Based on this phenomenon, a novel method for determination of quinolones has been developed by using a common spectrofluorometer to measure the intensity of fluorescence and SOS. The luminescence intensity is greatly enhanced by silver nanoparticles in the pH range 5.5–6.2. The calibration graphs for pipemidic acid (PPA) and lomefloxacin (LMFX) are linear in the range 2.0 × 10 −10 to 1.0 × 10 −5 and 1.0 × 10 −9 to 1.0 × 10 −5 mol L −1 , respectively. The limits of detection are 4.7 × 10 −11 mol L −1 for PPA and 1.1 × 10 −10 mol L −1 for LMFX. The method was applied satisfactorily to the determination of the two quinolones (Qs) in tablet, capsule, urine and serum samples. The experimental results showed that it is the certain size and certain concentration of silver nanoparticles that can greatly enhance the fluorescence -SOS intensity.

A simple electrogenerated chemiluminescence (ECL) analysis method for the determination of norfloxacin (NFLX) is reported. It is based on ECL produced by Na(2)SO(3), which is sensitized by the Tb-NFLX complex. The relative ECL intensity of the Tb(3+)-NFLX-Na(2)SO(3) system is proportional to the amount of NFLX. The optimized experimental conditions were investigated. The linear range and detection limit for NFLX were 1.0 x 10(-10)-8.0 x 10(-7) mol/L and 2.8 x 10(-11) mol/L, respectively. This method was successfully applied to the determination of NFLX in a capsule. NFLX in urine can be directly detected without pretreatment or separation.

The second-order scattering technique (SOS), using a common spectrofluorometer, was first developed as a sensitive instrumental analysis method for determination of the ribonucleic acid (RNA). The results indicate that RNA had a weak SOS peak and the Tb(III) ion can greatly enhance the SOS intensity of RNA with the maximum peak located at 612.0 nm. Mechanism study shows that the peak results from the long-range assembly of Tb(III) ion on the molecular surface of RNA. At the pH 7.50 and with cetyltrimethylammonium bromide (CTMAB) (6.0 × 10 −5 M), the enhanced SOS intensity was in proportion to the concentration of RNA in the range of 2.0 × 10 −8 to 2.0 × 10 −5 g/ml. The detection limit was 1.96 ng/ml. The relative standard deviation (five replicates) was within ±5% in the linear range. This method has been used satisfactorily for the determination of both synthetic and real samples. In comparison with most other methods for the determination of ribonucleic acids, this method is more sensitive.

A novel chemiluminescence (CL) flow injection method for the determination of pazufloxacin mesylate (PZFX) is described. It is based on CL of a KMnO4–Na2S2O4 system sensitized by the complex [Eu(PZFX)2]3+, and shows the intensive characteristic bands of Eu3+. The optimum conditions for CL emission were investigated. Under the optimum experimental condition, the linear range is 1.0×10−8–1.0×10−6 mol/L and the detection limit is 2.6×10−9 mol/L. The method was successfully applied to the determination of PZFX in serum and urine samples. The possible mechanism for this CL system is discussed. The project was supported by National Natural Science Foundation of China (20331010) and Natural Science Foundation of Beijing (2022007).

This paper firstly reports the second-order scattering (SOS) phenomenon in the nucleic acid system using a common spectrofluorometer. And a novel determination method of nucleic acids at nanogram level has been developed. Studies involving calf thymus DNA (ctDNA), fish sperm DNA (fsDNA) and yeast RNA (yRNA) showed that the SOS intensity of nucleic acids can be enhanced by La 3+ , Ce 3+ , Nd 3+ , Sm 3+ , Eu 3+ , Gd 3+ and Tb 3+ ion, of which Eu 3+ ion has the largest enhancement. And the intensity of the SOS is proportional to the concentration of nucleic acids. Maximum SOS peak at 550 nm appeared at pH 7.5 and 6.0 × 10 −5 mol l −1 CTMAB (cetyltrimethylammonium bromide). Under the optimal conditions, the calibration graphs were linear in the range of 1.0 × 10 −8 to 4.0 × 10 −5 g ml −1 for ctDNA, 6.0 × 10 −9 to 2.0 × 10 −6 g ml −1 for fsDNA, and 8.0 × 10 −9 to 1.0 × 10 −6 g ml −1 for yRNA, respectively. The detection limits were 1.7 ng ml −1 for ctDNA, 0.36 ng ml −1 for fsDNA and 0.21 ng ml −1 for yRNA, respectively. In comparison with most other methods for the determination of nucleic acids, this method is more convenient, more sensitive and simpler. And the possible mechanism was proposed.

A simple, rapid and highly sensitive fluorometric method for the determination of pazufloxacin mesilate (PZFX) is described. It is based on the formation of the complex [Tb(PZFX)2](3+), which shows the intensive characteristic bands of Tb3+. Optimum conditions for the determination were investigated. Under the optimum experimental condition, the fluorescence intensity responds linearly to the PZFX concentration in the range of 2.0 x 10(-8) - 5.0 x 10(-6) mol/l with a detection limit of 6.2 x 10(-9) mol/l. The method has been successfully applied to the determination of PZFX in urine and serum samples.

A simple flow injection chemiluminescence (CL) analysis method for the determination of europium in mineral samples is reported. It is based on luminescence produced by NaIO 4 –H 2 O 2 CL system sensitized by [Eu(EDTA)] − . The relative chemiluminescence intensity of the Eu 3+ –EDTA–NaIO 4 –H 2 O 2 system is proportional to the amount of Eu 3+ . The optimized experimental conditions were investigated. The linear range and detection limit for Eu 3+ are 2.0×10 −7 to 1.0×10 −5 and 6.2×10 −8 M, respectively. The sample throughput of the method is 80 samples/h. This method was successfully applied to the determination of europium in rare earth oxides. And the mechanism of chemiluminescence is proposed.

A novel rapid flow injection method with chemiluminescence (CL) detection was established for the determination of ciprofloxacin (CPLX), which is an antibiotic commonly used. The method is based on CL of Ce(IV)–SO 3 2− sensitized by Tb 3+ –CPLX, and showed the intensive bands characteristic of Tb 3+ ( 5 D 4 → 7 F 5 ). The optimum conditions for CL emission were investigated. The linear relationship between the relative CL intensity and the concentration of CPLX is in the range of 9.0×10 −9 –1.0×10 −6 mol/l with a detection limit of 3.1×10 −10 mol/l. The relative standard deviation is 2.8% ( n =11) for a level of 5.0×10 −8 mol/l. The method was applied to the analysis of CPLX in human serum and urine samples with satisfactory results. The possible mechanism for this sensitized CL reaction is also discussed.

A flow-injection chemiluminescence (CL) analysis for determination of pipemidic acid (PPA) is developed. It is based on luminescence produced by Ce(IV)–Na2SO3 CL system sensitized by Tb(PPA)2 3+. The relative chemiluminescence intensity of the Tb3+–PPA–Ce(IV)–Na2SO3 system is proportional to the amount of PPA. The optimized experimental conditions were determined. Accordingly, chemiluminescent method for the determination of PPA is proposed. The linear range and detection limit for PPA are 3.0 × 10−9–8.0 × 10−7 mol/L and 6.7 × 10−10 mol/L, respectively. The familiar excipients such as starch and dextrine do not cause interference. So this method can be applied to the determination of PPA in tablet. The content and recovery of PPA in urine can be directly detected without the pretreatment such as separation. And the mechanism of chemiluminescence is proposed.

A novel chemiluminescence (CL) flow system for rufloxacin (RFX) combined flow-injection analysis is presented in this paper. It is based on the energy transfer from RFX to europium(III), the intense luminescence instead of the weak CL produced by cerium(IV)–sulfurous acid–RFX CL system can be observed when Eu(III) was added to the system. A narrow and highly intense emission band at 617 nm arised from the excited-state Eu(III) was obtained. Under the optimum experimental conditions, the linear range was 2.0 × 10 −8 to 5.0 × 10 −7 M and the detection limit was 5.0 × 10 −9 M. The method has been successfully applied to determination RFX in dosage form, serum samples and urine samples. The recoveries were 95.0–104.9% for serum and urine samples. © 2001 Elsevier Science B.V. All rights reserved.

The phase relation of the ternary system Nd-Co-B quenched from 600 degrees C in the Go-rich region has been determined by means of X-ray powder diffraction. In this region there exist 11 ternary borides: Nd3Co13B2, NdCo4B, Nd5Co19B6, Nd3CO11B4, Nd2Co7B3, Nd2Co14B, NdCo12B6, NdCo4B4, Nd2Co5B3, NdCo2B2, and Nd2Co5B2 The first five borides are members of the homologous series Ndm+nCo5m+3nB2n (or NdCo5-xBx). New layered borides Nd3Co13B2 and Nd5Co19B6 have not been reported previously. The space group of them is P6/mmm and their crystal structures are refined by the Rietvled method. All the compounds of this Ndm+nCo5m+3nB2n family magnetically order between Te = 710 K for Nd3Co13B2 and To = 330 K for Nd2Co7B3. The mean cobalt moments of the Ndm+nCo5m+3nB2n, borides determined at 4.2 K are strongly dependent on the composition. On the basis of the experimental results, three kinds of Co sites with different magnetic moments are proposed. It is shown that increasing B content in NdCo5-xBx borides leads to an increase of the second-order crystal-field parameters Ate, which explains the enhancement of the magnetocrystalline anisotropy. Spin reorientations are observed in Nd3Co13B2 and Nd3CO11B4 compounds. The magnetic phase diagram of the Ndm+nCo5m+3nB2n borides is also given, and the behavior of magnetocrystalline anisotropy is analyzed using the single ion model.

A novel method for determination of trace amounts of tosufloxacin (TFLX) based on electrochemiluminescence (ECL) has been developed. The calibration graphs for TFLX were linear in the range of 5.0 x 10(-11)-3.5 x 10(-7) mol/L, with the detection limit of 1.3 x 10(-11) mol/L. Key factors affecting the determination of TFLX were investigated. TFLX amounts in capsule and serum samples were successfully detected by this method. A possible mechanism of energy transfer, and thus the explanation of ECL in the Tb3+-TFLX-Na2S2O4 system are discussed.

The phase relation of the ternary system Nd-Co-B quenched from 600 degrees C in the Go-rich region has been determined by means of X-ray powder diffraction. In this region there exist 11 ternary borides: Nd3Co13B2, NdCo4B, Nd5Co19B6, Nd3CO11B4, Nd2Co7B3, Nd2Co14B, NdCo12B6, NdCo4B4, Nd2Co5B3, NdCo2B2, and Nd2Co5B2 The first five borides are members of the homologous series Ndm+nCo5m+3nB2n (or NdCo5-xBx). New layered borides Nd3Co13B2 and Nd5Co19B6 have not been reported previously. The space group of them is P6/mmm and their crystal structures are refined by the Rietvled method. All the compounds of this Ndm+nCo5m+3nB2n family magnetically order between Te = 710 K for Nd3Co13B2 and To = 330 K for Nd2Co7B3. The mean cobalt moments of the Ndm+nCo5m+3nB2n, borides determined at 4.2 K are strongly dependent on the composition. On the basis of the experimental results, three kinds of Co sites with different magnetic moments are proposed. It is shown that increasing B content in NdCo5-xBx borides leads to an increase of the second-order crystal-field parameters Ate, which explains the enhancement of the magnetocrystalline anisotropy. Spin reorientations are observed in Nd3Co13B2 and Nd3CO11B4 compounds. The magnetic phase diagram of the Ndm+nCo5m+3nB2n borides is also given, and the behavior of magnetocrystalline anisotropy is analyzed using the single ion model.

In order to get red electroluminescence from a europium (Eu) complex with high efficiency, a hole-injection layer was inserted between the Eu-complex layer and an indium–tin–oxide electrode, and a hole-blocking layer was inserted between the Eu-complex and electron-transporting layers. To further improve the efficiency, devices having multiple-stacked Eu-complex (2.5 nm)/hole blocking (2.5 nm) units were fabricated. By stacking six units, the maximal luminance and emission efficiency of the red emission were increased to more than twice that from a device with a single Eu-complex layer.

The optical and electroluminescence properties of a light-emitting poly(arylene vinylene) derivative comprising triphenylamine as the arylene unit (TPA–PPV) are demonstrated. TPA–PPV is soluble in common organic solvents, and has a high photoluminescent (PL) quantum yield (ΦPL=0.94 in benzene). A single-layer light-emitting diode Indium–tin–oxide/TPA–PPV/Al utilizing blue–green light-emitting TPA–PPV as the emissive layer is fabricated, and luminance in excess of 612 cd/m2, turn-on voltages of 1.5 V, and high luminous efficiency (3.0 lm/w) are reported.

This paper reports the determination of ulifloxacin (UFX) by terbium-sensitized fluorescence using a second-order scattering method. UFX and Tb(III) ion form a fluorescence complex in aqueous solution, and its maximum excitation and emission wavelengths are located at 273 and 545 nm, respectively. In optimum conditions, the relative intensity at 545 nm has a linear relationship to the concentration of UFX in the range of 2.0 x 10(-8) - 1.0 x 10(-5) mol L(-1) and the detection limit is 3.9 x 10(-9) mol L(-1). The proposed method was applied to the determination of UFX in spiked human serum and urine satisfactorily. The luminescence property of UFX is also discussed by comparing with norfloxacin (NFLX) and ofloxacin (OFLX).

A photochemical chemiluminescence (CL) method for the determination of lomefloxacin (LFX) is proposed. LFX undergoes a photochemical reaction when irradiated with ultraviolet light, and a complex is formed when the photoproduct reacts with terbium(III), which can greatly enhance the CL of the Ce4+–Na2SO3 system. Under optimum experimental conditions, the linear range is between 9.0 × 10−10 and 1.0 × 10−5 M, and the detection limit is 2.2 × 10−10 M. The relative standard deviation for the determination of 5.0 × 10−8 M LFX was 3.0% (n = 11). The method has been successfully applied to the determination of LFX in dosage form, serum samples and urine samples. The recoveries were 97.9–102.3% for serum and urine samples. The possible mechanism is presented.

A simple, rapid and sensitive method for the determination of two fluoquinolones (FQs), enoxacin (ENX) and ofloxacin (OFLX) is described by using flow injection analysis with potassium permanganate-sodium sulfite chemiluminescence detection. The calibration graphs for ENX and OFLX are linear in the range of 8.0x10(-10)-1.0x10(-5) and 1.0x10(-9)-1.0x10(-6) mol l(-1), respectively. The 3sigma limits of detection are 2.4x10(-10) mol l(-1) for ENX and 5.6x10(-10) mol l(-1) for OFLX. The method is applied satisfactorily to the determination of the two FQs in dosage form and urine sample. The possible mechanism is also proposed.

A novel soluble Eu-complex was synthesized in order to obtain pure red-emitting organic EL devices and use of triplet excited state. The complex not only displays a high luminescent efficiency but also has a good solubility in common organic solvent. The electroluminescence properties of the complex were studied by fabricating and characterizing three layer light-emitting diodes containing poly(N-vinylcarbazole) doped with the complex as active layer, and an external quantum efficiency of 0.04 % was achieved.

An Eu-complex, europium tris(dibenzoylmethide) (triphenylphosphine oxide), was newly synthesized and utilized as a light-emitting material in electroluminescent devices. The complex was easily deposited as transparent and homogeneous thin films by vacuum sublimation,and was successfully applied to electroluminescent devices with a stacked structure of indium-tin-oxide (ITO)/hole transporting layer/Eu-complex layer/hole blocking layer/electron transporting layer/cathode. The devices with this structure gave off pure red light with luminance as high as 320 cd/m2. The hole-blocking layer was essential to obtain pure red light from this Eu-complex. Without the hole-blocking layer, holes passed through the Eu-complex layer and entered into the electron transporting layer, leading to yellow emission.

In this paper, we extend our previous work on the interaction between Ln(NO 3 ) 3 (Ln=Nd, Eu, Tb, Er) and DMSO in anhydrous acetonitrile (MeCN) 12,17 to all the remaining members of the Ln series, with the exception of Pm. The reported coordination numbers represent the first consistent series of such data for Ln(III) ions in organic solution. Apparent stability constants for the coordination of DMSO are also evaluated and discussed