Synthesis of a terbium fluorescent chelate and its application to time-resolved fluoroimmunoassay

A new nonadentate ligand, N, N, N-1, N-1-[2,6-bis(3'-aminomethyl-1 1'-pyrazolyl)-4-phenylpyridine]tetrakis(acetic acid) (BPTA) for a Tb3+ fluorescent complex was synthesized. The Tb3+ complex is strongly fluorescent, having a large fluorescence quantum yield of 1.00 and very long fluorescence lifetime of 2.681 ms in 0.05 M berate buffer of pH 9.1. Streptavidin (SA) was labeled with SPTA by using its succinimidyl monoester, and the BPTA-Tb3+-labeled SA was used in sandwich-type time-resolved fluoroimmunoassay (TR-FIA) of alpha -fetoprotein (AFP) and carcinoembryonic antigen (CEA) in human sera. The Tb3+-labeled SA was also used in competitive type TR-FIA of bensulfuron- methyl (BSM) in water. The detection limits of these assays are 42 pg/mL for AFP, 70 pg/mL for CEA, and 0.4 ng/mL for BSM. In addition, a new simultaneous measurement method for AFP and CEA in a human serum sample was developed by using 4,4'-bis(1 " ,1 " ,1 " ,2 " ,2 " ,3 " ,3 " -heptafluoro-4 " ,6 " -hexanedion-6 " -yl)chlorosulfo-o-terphenyl ((BHHCT)-Eu3+-labeled anti-AFP antibody, biotinylated anti-CEA antibody, and BPTA-Tb3+-labeled SA. The concentrations of AFP and CEA in 39 human serum samples were determined, and the results were compared with those of the independently determined AFP and CEA by TR-FIA with a single-label method. A good correlation was obtained with the correlation coefficients of 0.991 for AFP and 0.994 for CEA.

Rapid authentication of ginseng species using microchip electrophoresis with laser-induced fluorescence detection

Ginseng is one of the most expensive Chinese herbal medicines and the effectiveness of ginseng depends strongly on its botanical sources and the use of different parts of the plants. In this study, a microchip electrophoresis method coupled with the polymerase chain reaction (PCR)-short tandem repeats (STR) technique was developed for rapid authentication of ginseng species. A low viscosity hydroxypropyl methylcellulose (HPMC) solution was used as the sieving matrix for separation of the amplified STR fragments. The allele sizing of the amplified PCR products could be detected within 240 s or less. Good reproducibility and accuracy of the fragment size were obtained with the relative standard deviation for the allele sizes less than 1.0% (n = 11). At two microsatellite loci (CT 12, CA 33), American ginseng had a different allele pattern on the electropherograms compared with that of the Oriental ginseng. Moreover, cultivated and wild American ginseng can be distinguished on the basis of allele sizing. This work establishes the feasibility of fast genetic authentication of ginseng species by use of microchip electrophoresis.

A collinear light-emitting diode-induced fluorescence detector for capillary electrophoresis

A novel fluorescence detector based on collinear scheme using a brightness light-emitting diode emitting at 470 nm as excitation source is described. The detector is assembled by all-solid-state optical-electronic components and Coupled with capillary electrophoresis using on-column detection mode. Fluorescein isothiocyanate (FITC) and FITC-labeled amino acids and small molecule peptide as test analyte were used to evaluate the detector. The concentration limit of detection for FITC-labeled phenylalanine was 10 nM at a signal-to-noise ratio (S/N) of 3. The system exhibited good linear responses in the range of 1 x 10(-7) to 2 x 10(-5) M (R-2 = 0.999). (c) 2004 Elsevier B.V. All rights reserved.

Simultaneous light emitting diode-induced fluorescence and contactless conductivity detection for capillary electrophoresis

A combined detection system of simultaneous contactless conductometric and fluorescent detection for capillary electrophoresis (CE) has been designed and evaluated. The two processes share a common detection cell. A blue light-emitting diode (LED) was used as the excitation source and an optical fiber was used to collect the emitting fluorescence for fluorescent detection (FD). Inorganic ions, fluorescein isothiocyanate (FITC)-labeled amino acids and small molecule peptides were separated and detected by the combined detector, and the detection limits (LODs) of sub-μ M level were achieved.

The surface sites of sulfated zirconia studied in situ by laser-induced fluorescence spectroscopy

The surface sites of sulfated zirconia were investigated in situ by laser-induced fluorescence spectroscopy using aniline as the probe molecule. Different from the cases for many other oxides, the aniline adsorbed on the unique active sites of sulfated zirconia at r.t. is changed into another species, which emits a characteristic fluorescence band at 422 nm. The results illustrate that the sulfate groups in sulfated zirconia are favorable for the generation of these unique active sites, which also rarely exist on pure zirconia composed of tetragonal and monoclinic phases but do not exist on pure zirconia composed of monoclinic phase. (C) 2004 Elsevier B.V. All rights reserved.

Colorimetric and ratiometric fluorescence sensing of fluoride: Tuning selectivity in proton transfer

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The Stokes experiment in a foam - a summary

Sponsorship: EPSRC

Typically Anti-American? The Labour movement, America and Broadcasting in Britain from Beveridge to Pilkington, 1949-62

O'Malley, T. (2007). Typically Anti-American?: The Labour movement, America and Broadcasting in Britain from Beveridge to Pilkington, 1949-62. In J. Wiener and M. Hampton (Eds.), Anglo- American Media Interactions,1850-2000 (pp.234-253). Basingstoke: Palgrave Macmillan. RAE2008