Fluorescein detector

Fe-TPAA Fe(III)-tris[N-(2-pyridylmethyl)-2-aminoethyl] amine Fe-TPEN Fe(II)-tetrakis-N,N,N, N -(2-pyridyl methyl-2-aminoethyl)amine FFA Free fatty acids FGF Fibroblast growth factor FID Flame ionization detector FITC Fluorescein isothiocyanate FKBP FK506-binding protein FLAP 5-lipoxygenase-activating protein... 

Wu S, Dovichi NJ (1989) High-sensitivity fluorescence detector for fluorescein isothiocyanate derivatives of amino acids separated by capillary zone electrophoresis. J Chromatogr 480 141-155... 

Valproic acid has been determined in human serum using capillary electrophoresis and indirect laser induced fluorescence detection [26], The extract is injected at 75 mbar for 0.05 min onto a capillary column (74.4 cm x 50 pm i.d., effective length 56.2 cm). The optimized buffer 2.5 mM borate/phosphate of pH 8.4 with 6 pL fluorescein to generate the background signal. Separation was carried out at 30 kV and indirect fluorescence detection was achieved at 488/529 nm. A linear calibration was found in the range 4.5 144 pg/mL (0 = 0.9947) and detection and quantitation limits were 0.9 and 3.0 pg/mL. Polonski et al. [27] described a capillary isotache-phoresis method for sodium valproate in blood. The sample was injected into a column of an EKI 02 instrument for separation. The instrument incorporated a conductimetric detector. The mobile phase was 0.01 M histidine containing 0.1% methylhydroxycellulose at pH 5.5. The detection limit was 2 pg/mL. 

Fig. 31 (A) Principle of a sandwich immunoassay using FDA particulate labels. The analyte is first immobilized by the capture antibody preadsorbed on the solid phase (a) and then exposed to antibody-coated microparticle labels (b). Every microparticle contains 108 FDA molecules. High signal amplification is achieved after solubilisation, release, and conversion of the precursor FDA into fluorescein molecules by the addition of DMSO and NaOH (c). (B) Calibration curves of IgG-FDA microcrystal labels with increasing surface coverage of detector antibody (a-d) compared with direct FITC-labeled detector antibody (e). The fluorescence signals increase with increasing IgG concentration. FDA microcrystals with a high IgG surface coverage (c,d) perform better than those with lower surface coverage (a,b). (Reprinted with permission from [189]. Copyright 2002 American Chemical Society)...

In another application of multiple position detection, a cooled CCD detector has been used to detect four spots of fluorescein-labeled HSA, which bind to anti-HSA antibody that is immobilized on a fused silica plate.(134) Irradiation of the waveguide at a 70° angle of incidence on the top surface generates an evanescent wave in the waveguide. The CCD is positioned parallel to the top surface of the waveguide to capture the emission of the labeled HSA. Three-dimensional images of the scans are shown in this study. 

Figure 5.11 illustrates the basic performance of the on-line MS assay. For comparison, a homogenous fluorescence assay has been set up in parallel. For this purpose, the carrier flow was split after the second microcoU reactor, with 90% of the total flow being directed to a fluorescence detector (Fig. 5.11a) and 10% to the MS (Fig. 5.11b). The affinity interaction between streptavidin and biotin was chosen to study the characteristics of an on-line MS biochemical assay. Fluorescein-biotin was used as reporter ligand for both fluorescence and MS in the SIM mode (m/z 390) detection. In the fluorescence mode, the homogeneous biochemical assay is based on the quenching of the fluorescein-biotin fluorescence upon binding to streptavidin.

Fig. 2 Determination of IgE using aptamer-based APCE. (A) Electropherograms obtained for 500 nM of A with 0 (left) and 500 nM (right) IgE. Migration buffer was 10 mM phosphate at pH 7.4, and 10 nM fluorescein was used as internal standard (IS). Injector-to-detector length was 20 cm. (B) Separation of same solutions in 10 mM phosphate at pH 8.2 and gravity-induced flow of 0.02 cm/s. (C) Solutions of 300 nM of A with no IgE (left), 300 nM IgE (middle), and 1 nM IgE (right) were separated with injector-to-detector length of 7 cm. After 48 s of separation, a vacuum was applied to the outlet to rapidly pull the complex to the detector. 4(5)-Carboxyfluorescein (5 nM) was used as internal standard. Fluorescent signal scale for the 1 nM IgE sample is expanded by 10-fold relative to the other electropherograms. (From Ref. 26.)...

Wavelength dependence of detector response can also be compensated by using a fluorescent screen in front of the photocell or photomultiplier. This screen acts as a quantum counter. A concentrated solution of Rhodamin B in glycerol (3g per litre) or fluorescein in 0.01N NajCO, has been used for this purpose. Quantum counters work on the principle that whatever be the wavelength of radiation incident on the screen, if completely absorbed, the photodetector sees only the wavelength distribution of fluorescence from the dye. It requires that the fluorescence yield of the counter material be independent of wavelength of excitation and therefore that its emission intensity is directly proportional to the incident intensity. 

FAMOS FIA FID FMG FTIR FTOL FVM Pulsing frequency Fraunhofer-Allianz Modulares Mikroreaktionssystem Flow injection analysis Flame ionization detector Fluorescein mono-P-D-galactopyranoside Fourier transform infrared Fluorescence-turn-off length Finite volume method... 

FIGURE 5.3 Electropherograms of fluorescein and BODIPY separations (a) without and (b) with field-amplified sample stacking. Fluorescence signal is normalized with exposure time in both plots. The position of the detector is 10 mm from the downstream channel intersection of the chip. The signal increase is 1100-fold for the stacked case, and resolution increases from 3 to 120 [584]. Reprinted with permission from Wiley-VCH Verlag. 

Fluocinolone acetonide, 625 Fluocinolone acetonide acetate, 625 Fluocinonide, 625 Fluocortolone, 625 Fluocortolone caproate, 625 Fluocortolone hexanoate, 625 Fluocortolone pivalate, 625 Fluocortolone trimethylacetate, 625 Fluoderm, 625 Fluonid, 625 Fluopromazine, 626 Fluopromazine hyck ochloride, 626 Fluorandrenolone, 630 Fluorescein solution, 1169 Fluorescence detector, 203... 

The earliest applications of acoustic levitation in analytical chemistry were concerned with the development of various steps of the analytical process. Thus, Welter and Neidhart [72] studied the preconcentration of n-hexanol in methanol by solvent evaporation and the liquid-liquid extraction of n-hexanol from water to toluene in a levitated droplet, which they found to be efficient when using GC-FID with n-pentanol as internal standard. Solvent exchange of fluorescein from methylisobutyl ketone to aqueous sodium hydroxide was also accomplished. Sample concentration in an acoustically levitated droplet prior to injection into a CE equipped with an LIF or UV detector has also been accomplished [73,118]. The target analytes (namely, dansylated amino acids) were concentrated in the levitated drop and a limit of detection of 15 nM — much lower than the 2.5 pM achieved by hydrodynamic injection without preconcentration — was achieved following CE separation and quantification. For this purpose, 36000 sample droplets 2.3 pi in volume each were sequentially positioned in the acoustic Ievitator and evaporated. This example illustrates the potential of acoustic levitation for coupling to any type of detector for micro- or nanotrace analyses. 

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